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121 Appendix C: Case Studies C.1 Denali 2002 [Earthquake] Table C-1. Denali Earthquake. Case Study Name/Date Denali Earthquake (2002) Location Alaska, USA Event Type Earthquake Bridge Name Tok Cutoff Bridge & Tanana River Bridge Scope/Costs Six bridges damaged, two discussed in this report Planning Techniques/Tools Incident Command System (ICS) training for some officials Event Response Use of ICS with inspection stations to deploy inspectors across the state rapidly Assessment Techniques/Tools Visual Inspections Rapid Restoration Type Immediate temporary repairs followed by permanent repairs Innovations • Using the ICS to set up inspectors across the state to be able to access the damage quicker • Multijurisdictional inspections to sped up assessment process C.1.1 Introduction On November 3rd, 2002, a 7.9 magnitude earthquake occurred on the Denali Fault in Alaska. This very large seismic event was felt as far as Pennsylvania and Louisiana and provided the Alaska Department of Transportation and Public Facilities (ADOT&PF) officials with the opportunity to test their Incident Command System (ICS) procedures and identify areas that could be improved. Not all responders received formal ICS training before the earthquake, so many were learning on the fly. Crews adapted quickly, and all 200 damaged bridges received Level II inspections to confirm initial damages reported within 48 hours of the earthquake. (McCarthy 2003). C.1.1.1 Event Response About an hour after the earthquake, Alaska DOT&PF formed an Emergency Operations Center (EOC) in conjunction with the Alaskan State Troopers, the media, and the public, to keep everyone informed as changes arose (McCarthy 2003). After the EOC was established, the Alaska DOT&PF maintenance crews followed the ICS model to establish stations across the state as bases for inspections. Officials also adhered to the Alaska Emergency Operations Plan to guide state and local authorities on how to respond to a major earthquake and used the State’s Emergency Highway Traffic Regulation, which provided guidance on deploying the military to help manage traffic in such situations (McCarthy 2003).

1 2 2C.1.2 Emergency PlanningT o p r e p a r e f o r a s e i s m i c e v e n t , A l a s k a D O T & P F h a d e s t a b l i s h e d t h e E m e r g e n c y O p e r a t i o n s P l a n a n d a n E m e r g e n c y H i g h w a y T r a f f i c R e g u l a t i o n M a n u a l t o g u i d e o f f i c i a l s d u r i n g t h e e v e n t . T h e s e p r o c e d u r e s a n d d o c u m e n t s f o l l o w e d t h e n a t i o n a l l y r e c o g n i z e d I C S a p p r o a c h t o e m e r g e n c y r e s p o n s e a n d w e r e u t i l i z e d i n t h e r e s p o n s e . C.1.3 AssessmentL e v e l I i n s p e c t i o n s o f b r i d g e s i n t h e a r e a w e r e c o n d u c t e d b y A l a s k a D O T & P F m a i n t e n a n c e f o r e m e n . L e v e l I i n s p e c t i o n s c o n s i s t e d o f v i s u a l i n s p e c t i o n s l o o k i n g f o r c r a c k s , s e t t l e m e n t , a n d e m b a n k m e n t s l i d e s . A n y m a j o r d a m a g e s w e r e q u i c k l y r e p o r t e d , a n d m a i n t e n a n c e c r e w s f i x e d t e m p o r a r y r e p a i r s o n t h e s p o t i n m a n y c a s e s . A l l t e m p o r a r y r e p a i r s a n d L e v e l I i n s p e c t i o n s w e r e c o m p l e t e d w i t h i n 2 4 h o u r s . T h i s e f f i c i e n c y w a s m a d e p o s s i b l e b y t h e e s t a b l i s h m e n t o f i n s p e c t i o n s t a t i o n s ( M c C a r t h y 2 0 0 3 ) . A f t e r t h e L e v e l I i n s p e c t i o n s w e r e c o m p l e t e d , L e v e l I I i n s p e c t i o n s w e r e c o n d u c t e d o n s t r u c t u r e s w i t h h i g h e r l e v e l s o f d a m a g e b y m e m b e r s o f t h e B r i d g e D e s i g n S e c t i o n o f t h e A l a s k a D O T & P F . T h e s e c r e w s f l e w u p f r o m J u n e a u a n d c o m p l e t e d a l l L e v e l I I i n s p e c t i o n s w i t h i n 4 8 h o u r s ( M c C a r t h y 2 0 0 3 ) , w h i c h i n c l u d e d a s s e s s m e n t s o f o v e r 2 0 0 b r i d g e s ( A l i p o u r 2 0 1 6 ) . B e c a u s e t h e m a i n p r i o r i t y w a s t o r e o p e n t r a n s p o r t a t i o n r o u t e s i n A l a s k a , j u r i s d i c t i o n a l b a r r i e r s w e r e s e t a s i d e s u c h t h a t i n s p e c t i o n s w e r e n o t l i m i t e d t o s t a t e - o w n e d b r i d g e s b u t a l s o i n c l u d e d s e v e r a l c i t y a n d c o u n t y s t r u c t u r e s . F o o t p r i n t s l e f t i n t h e s n o w c o n f i r m e d w h i c h b r i d g e s h a d a l r e a d y u n d e r g o n e a L e v e l I i n s p e c t i o n b e f o r e B r i d g e E n g i n e e r s h a d a r r i v e d t o c o m p l e t e L e v e l I I i n s p e c t i o n s ( M c C a r t h y 2 0 0 3 ) .C.1.4 Rapid RestorationC.1.4.2 Permanent StructureD u r i n g i n s p e c t i o n s , t w o b r i d g e s w e r e i d e n t i f i e d a s n e e d i n g r e p l a c e m e n t s . T h e s e s t r u c t u r e s f a i l e d d u e t o t h e i r s h e e t p i l e w a l l a b u t m e n t d e s i g n , w h i c h s u f f e r e d s e v e r e l a t e r a l d i s p l a c e m e n t d u e t o l i q u e f a c t i o n . E v e n t h o u g h t h e y w e r e d e e m e d s a f e e n o u g h t o c a r r y t r a f f i c l o a d s , t h e A l a s k a D O T & P F d e c i d e d t o r e p l a c e t h e s t r u c t u r e s , a s o f f i c i a l s w e r e s k e p t i c a l i f t h e b r i d g e s c o u l d w i t h s t a n d a n o t h e r e a r t h q u a k e . S e v e r a l o t h e r b r i d g e s s u f f e r e d m i n o r t o m o d e r a t e d a m a g e , i n c l u d i n g t h e T o k C u t o f f B r i d g e , w h o s e a b u t m e n t m o v e d t e n i n c h e s f r o m i t s o r i g i n a l p o s i t i o n ( F i g u r e C - 1 ) . T h i s d i s p l a c e m e n t c a u s e d a n i n c r e a s e i n s t r e s s e s o n t h e s u p e r s t r u c t u r e , r e q u i r i n g c r e w s t o r e p l a c e t w o s p a n s o f t h e b r i d g e ( A l i p o u r 2 0 1 6 ) . O n e t r u s s b r i d g e e x p e r i e n c e d a s h i f t e d r o c k e r b e a r i n g . L u c k i l y , t h e s h i f t e d p i n a n d b e a r i n g d i d n o t s e p a r a t e , s o m a i n t e n a n c e c r e w s w e r e a b l e t o j a c k t h e b r i d g e u p a n d p u s h t h e p i n s b a c k i n t o t h e i r o r i g i n a l s l o t s . O l d r a i l r o a d r a i l s w e r e w e l d e d t o g e t h e r a n d u s e d a s p i l e s i n t h e o r i g i n a l c o n s t r u c t i o n . H o w e v e r , t h e s e f a i l e d a f e w y e a r s l a t e r d u e t o t h e b r i t t l e m a t e r i a l a n d h a d t o b e r e p l a c e d d u r i n g t h e r e p a i r . Figure C-1. Shifting of the Tok Cutoff Bridge (McCarthy 2003)

123 The steel supports of a span of the Tanana River Bridge, built in 1943, shifted four inches. For the repair, the span (weighing 1.1. million pounds) was lifted back into its original place followed by installation of lateral restraints and repair of expansion joints (McCarthy 2003). C.1.5 Challenges The most challenging aspect of coordinating the response of the Denali Earthquake was the transition between the response and recovery phases. With many moving pieces, it was difficult to manage multiple jurisdictions and to communicate clearly to ensure everyone was on the same page. Furthermore, only those officials in the northern part of the state had any formal ICS training; many were learning on the job. Despite this lack of experience, crews adapted quickly and were able to provide a controlled and efficient response (McCarthy 2003). Another challenge was the weather conditions. Luckily, crews did not have to fight a snowstorm, but the unknown weather forecast forced a rapid repair process. Furthermore, most Alaskan maintenance does not take place during the winter. Crews had to learn not only how to make these mid-season fixes, but also how to repair them again in the spring and summer, as many were meant to be temporary or did not survive the harsh winter (McCarthy 2003). C.1.6 Innovations and Lessons Learned C.1.6.3 Emergency Response and Management Most of the lessons learned from the Denali Earthquake were related to emergency response and management. Improved record keeping of damages for cost-estimates and coordination with inspectors and recorders was needed, as in many instances, repairs were already completed by maintenance crews before photos could be taken of the damage. Additional training for all officials and mandatory ICS training were later required for crews after the earthquake to improve the preparations for the next event (McCarthy 2003).

1 2 4C.2 Japan 2011 [Earthquake and Tsunami] Table C-2. Japan Earthquake and Tsunmai Case Study Name/ Date Japan Earthquake and Tsunami (2011)L ocation JapanEvent Type Earthquake/ TsunamiBridge Name SeveralScope/ Costs About 200 bridges total damagePlanning Techniques/ Tools N/ AEvent Response Multiple global and local research teams to analyze and assess the damageAssessment Techniques/ Tools V isual inspection, photographs, and videosRapid Restoration Type Temporary structures, FRP repairsInnovations • Mass deployment of temporary structures• Importance of retrofits to reduce likelihood and extent of damageC.2.1 IntroductionO n M a r c h 1 1 , 2 0 1 1 , t h e 9 . 0 m a g n i t u d e G r e a t E a s t J a p a n E a r t h q u a k e s t r u c k m u c h o f t h e n a t i o n . T h e e a r t h q u a k e s u b s e q u e n t l y c a u s e d a t s u n a m i , d e s t r o y i n g e n t i r e c o m m u n i t i e s , a s s h o w n i n F i g u r e C - 2 . I m p o s i n g e n o r m o u s d a m a g e a n d c a u s a l i t i e s , t h e e a r t h q u a k e a n d t s u n a m i l e f t w i t h a n o p p o r t u n i t y f o r r e s e a r c h e r s a n d p r a c t i t i o n e r s t o v e r i f y t h e r e s i l i e n c e o f s t r u c t u r e s a n d i n f r a s t r u c t u r e . A m i d m a n y o t h e r f a c t o r s , r e s e a r c h e r s w e r e a b l e t o i n v e s t i g a t e t h e e f f e c t i v e n e s s o f t h e s e i s m i c d e s i g n f e a t u r e s a d d e d t o m a n y s t r u c t u r e s a f t e r t h e 1 9 7 8 M i y a g i - k e n - o k i a n d 1 9 9 5 K o b e e a r t h q u a k e s a n d h o w t o i m p l e m e n t t s u n a m i - r e s i l i e n t s t r u c t u r e s i n t h e f u t u r e . O n e p i e c e o f e v i d e n c e f o r ‘ g o o d p r a c t i c e ’ i s t h a t m a n y o f t h e b r i d g e s t h a t d i d n o t s u s t a i n s e v e r e d a m a g e i n t h e 2 0 1 1 e a r t h q u a k e h a d b e e n r e p a i r e d o r r e t r o f i t t e da f t e r t h e 1 9 7 8 a n d 1 9 9 5 e a r t h q u a k e s , s h o w i n g t h e b e n e f i t s o f l i f e c y c l e i n t e r v e n t i o n m e a s u r e s ( K a w a s h i m a& M a t s u z a k i 2 0 1 2 ) . C.2.1.1 Event Response M a n y d i s a s t e r r e c o n n a i s s a n c e t e a m s c o n s i s t i n g o f r e s e a r c h e r s a n d p r o f e s s i o n a l s w e r e q u i c k l y d e p l o y e d a f t e r t h e e a r t h q u a k e a n d t s u n a m i t o a s s e s s a n d a n a l y z e t h e d a m a g e . T e a m s w e r e m a d e u p o f d o m e s t i c a n d g l o b a l m e m b e r s f r o m d i f f e r e n t p r o f e s s i o n s o f C i v i l E n g i n e e r i n g . M o s t t e a m s w e r e g r o u n d - b a s e d , a n d m a j o r r e c o n n a i s s a n c e t e c h n i q u e s i n c l u d e d t h e u s e o f d i g i t a l p h o t o s / v i d e o s a t t h e g r o u n d l e v e l . M a n y f i r s t r e s p o n d e r s w e r e a s s i s t e d b y t h e g e o s p a t i a l t o o l s a n d r e m o t e s e n s i n g p r o d u c t s . S o m e p e r f o r m e d n u m e r i c a l a n a l y z e s t o b e t t e r u n d e r s t a n d w h a t o c c u r r e d . Figure C-2. Utatsu Bridge Flooded (Kawashima & Matsuzaki, 2012)

1 2 5C.2.2 Emergency PlanningC.2.2.2 Crowdsourcing and Information Gathering D u r i n g t h e e a r t h q u a k e a n d t s u n a m i , w i t n e s s e s c a p t u r e d p h o t o s a n d v i d e o s o f t h e d a m a g e . M a n y l o c a l c i t i z e n s p o s t e d s t r i k i n g i m a g e s a n d v i d e o s o n s o c i a l m e d i a i n c l u d i n g T w i t t e r , F a c e b o o k , a n d Y o u T u b e , w h i c h b r o a d c a s t e d t o t h e i n t e r n a t i o n a l c o m m u n i t y t i m e l y a n d v i v i d l y a b o u t t h e s e v e r i t y o f t h e d i s a s t r o u s f o r c e s , f r o m t h e s e i s m i c s h a k i n g t o t h e t s u n a m i w a v e s . S e c u r i t y c a m e r a s w e r e a n o t h e r s o u r c e f o r c o l l e c t i n g r e a l - t i m e e v i d e n c e . T h i s i m a g e r y d a t a w a s t h e n a n a l y z e d t o b e t t e r u n d e r s t a n d w h a t c a u s e d s o m e s t r u c t u r e s t o f a i l ( o r i n s o m e c a s e s n o t ) , a n d t o s e e w h e r e f u t u r e d e s i g n s c o u l d b e i m p r o v e d f o r b u i l d i n g o r r e t r o f i t t i n g m o r e r e s i l i e n t e a r t h q u a k e a n d t s u n a m i s t r u c t u r e s . C.2.3 AssessmentM o s t o f t h e d a m a g e a s s e s s m e n t w a s b a s e d o n v i s u a l i n s p e c t i o n i n t h e f i e l d , p h o t o g r a p h s , a n d v i d e o s . I n s o m e c a s e s , b u o y a n c y c a l c u l a t i o n s w e r e c o n d u c t e d t o v e r i f y t h e c a u s e o f u p l i f t i n g o f s p a n s f r o m t h e t s u n a m i . S e i s m i c l o a d s w e r e a l s o c a l c u l a t e d , a n d t h e s e c o n s i d e r e d t h e d e a d w e i g h t o f t h e s t r u c t u r e , t h e e l a s t i c s e i s m i c c o e f f i c i e n t , a n d a n o v e r s t r e n g t h f a c t o r ( K a w a s h i m a a n d M a t s u z a k i 2 0 1 2 ) . J a p a n b r e a k s d o w n i t s b r i d g e d a m a g e l e v e l s b y t h e d a m a g e s t a t e s o f A , B , C a n d D . E a c h d a m a g e s t a t e h a s a c o r r e s p o n d i n g d e s c r i p t i o n f o r e i t h e r c o n c r e t e p i e r s o r c o n c r e t e g i r d e r s d e s c r i b i n g w h a t d a m a g e w o u l d o c c u r w i t h t h a t d a m a g e s t a t e . F o r f l e x u r a l a n d s h e a r f a i l u r e s , d a m a g e d e g r e e s w e r e a s s i g n e d b a s e d o n v i s u a l o b s e r v a t i o n s ( S a i n i a n d S a i i d i 2 0 1 3 ) . C.2.3.3 Earthquake DamageC.2.3.3.1 Yuriage BridgeA t t h e Y u r i a g e B r i d g e , t s u n a m i w a v e s p a s s e d u n d e r t h e s t r u c t u r e , b u t w e r e n o t i n t e n s e e n o u g h t o g e n e r a t e a n y s i g n i f i c a n t d a m a g e , a n d t h e o b s e r v e d d a m a g e w a s a t t r i b u t e d t o s e i s m i c m o t i o n s ( E E R I 2 0 1 1 ) . T h i s d a m a g e w a s c o n c e n t r a t e d a t t h e s t e e l r o l l e r b e a r i n g s . S e i s m i c m o t i o n s b u i l t u p s t r e s s e s a t t h e b e a r i n g s , w h e r e f a i l u r e w a s o b s e r v e d . T h e b r i d g e a l s o e x p e r i e n c e d d a m a g e a t t h e e n d s o f i t s p r e s t r e s s e d g i r d e r s , w h i c h w a s a t t r i b u t e d t o r a d i a l s t r e s s e s o r i g i n a t i n g a t t h e b e a r i n g ( K a w a s h i m a 2 0 1 2 ) . T h e b e a r i n g d a m a g e w a s a l s o t h o u g h t t o b e c a u s e d b y p i e r m o v e m e n t , w h i c h w a s c a u s e d p a r t i a l l y b y l i q u e f a c t i o n . T h i s c a u s e d a v e r t i c a l s h i f t o n t h e d e c k o f 6 c m , a n d a h o r i z o n t a l s h i f t o f 5 c m . T h e s e m e a s u r e m e n t s w e r e p e r f o r m e d d u r i n g f i e l d v i s i t s a s s h o w n i n F i g u r e C - 3 A ( J a p a n B r i d g e E n g i n e e r i n g C e n t e r 2 0 1 1 ) . C.2.3.3.2 Tennoh BridgeT h i s s t e e l b r i d g e s u f f e r e d r u p t u r e a n d l o c a l b u c k l i n g t o i t s b r a c e s . O n e o f t h e g u s s e t p l a t e s a l s o d i s c o n n e c t e d d u e t o c o r r o s i o n a n d t o r s i o n , a s s h o w n i n F i g u r e C - 3 B ( K a w a s h i m a 2 0 1 2 ) . B e a r i n g b o l t s a l s o f r a c t u r e d , a n d t h e i r c h u n k s w e r e l a y i n g n e a r t h e c o n n e c t i o n s . T h e e x p a n s i o n j o i n t p r o t e c t o r w a s d i s l o d g e d d u e t o t h e s e f r a c t u r e d b o l t s . O n t h e b r i d g e d e c k , t h e t e e t h - l i k e e x p a n s i o n j o i n t s u f f e r e d e x t r e m e s e p a r a t i o n f r o m l o n g i t u d i n a l m o t i o n ( J a p a n B r i d g e E n g i n e e r i n g C e n t e r 2 0 1 1 ) . Figure C-3. Earthquake Damage Observed Yuriage Bridge Damage (Japan Bridge Engineering Center 2011)

1 2 6C.2.3.3.3 Sendai-Tobu Viaduct T h e v i a d u c t w a s u n d e r c o n s t r u c t i o n d u r i n g t h e e a r t h q u a k e . I t w a s b e i n g w i d e n e d , a n d t h e c r e w s w e r e i n t h e p r o c e s s o f c o n n e c t i n g t h e o n a n d o f f r a m p s b e f o r e t h e d i s a s t e r ( K a w a s h i m a 2 0 1 1 ) . T h e s e t - u p o f c o n s t r u c t i o n s c a f f o l d i n g d i d m a k e i t e a s i e r t o a c c e s s t h e b r i d g e f o r i n s p e c t i o n ( K u w a b a r a a n d Y e n n . d . ) . T h e e l a s t o m e r i c b e a r i n g s r u p t u r e d a n d d e t a c h e d f r o m t h e i r s t e e l p l a t e s . T h i s w a s a t t r i b u t e d t o e x t r e m e r e l a t i v e d i s p l a c e m e n t s b e t w e e n t h e d e c k j o i n t s i n t h e t r a n s v e r s e d i r e c t i o n , w h i c h l e d t o g r e a t s h e a r f o r c e s ( K a w a s h i m a 2 0 1 2 ) . A d d i t i o n a l l y , e x t r e m e t e n s i o n f o r c e s w e r e a l s o f o u n d t o p l a y a r o l e i n t h e f a i l u r e . I n t o t a l , 1 8 e l a s t o m e r i c b e a r i n g s a n d 4 0 o f t h e s t e e l s t o p p e r s f a i l e d . F u r t h e r m o r e , t h e s p a n s w i t h t w o d i f f e r e n t t y p e s o f b e n t s ( i n t h i s c a s e h a m m e r h e a d v s . p i e r ) b e h a v e d d i f f e r e n t l y , c r e a t i n g t o r s i o n d e m a n d s i n t h e s u p e r s t r u c t u r e w h i c h a d d e d s t r e s s t o t h e b e a r i n g s ( E E R I 2 0 1 1 ) . C.2.3.3.4 Shida Bridge and Levee V i s u a l i n s p e c t i o n s f o u n d t h a t o n e o f t h e f i x e d b e a r i n g s d r o p p e d o f f t h e i r s e a t s , a n d a n o t h e r s u f f e r e d s h e a r e d a n c h o r - b o l t s . A l s o , o n e o f t h e a b u t m e n t s s e t t l e d , w h i c h w a s c a u s e d b y r e d u c e d s o i l c a p a c i t y . T h e s e f a c t o r s l e d t o a h i g h l y v i s u a l d r o p i n t h e r o a d d e c k a t p i e r 3 . A t o t h e r p i e r l o c a t i o n s , t h e r e w a s s o m e s e v e r e c r a c k i n g a n d y i e l d i n g ( E E R I 2 0 1 1 ) . C.2.3.3.5 Ezaki Ohashi BridgeT h i s 9 - s p a n c o n t i n u o u s b r i d g e s u f f e r e d s h e a r c r a c k s , c o n c r e t e s p a l l i n g , a n d b u c k l e d l o n g i t u d i n a l b a r s a t t h e p i e r s . T o r e p a i r t h e c o l u m n s , c o n f i n i n g F i b e r - r e i n f o r c e d p o l y m e r ( F R P ) w a s u s e d t o i n c r e a s e t h e i r a x i a l c a p a c i t y , c r e a t i n g a s m o o t h f i n i s h ( K u w a b a r a & Y e n n . d . ) . 1.1.1. Tsunami DamageC.2.3.3.6 Utatsu BridgeT h e U t a t s u B r i d g e s u f f e r e d a f l e x u r a l f a i l u r e a t o n e o f t h e c o l u m n s a s s h o w n i n F i g u r e C - 4 , e v e n t h o u g h i t w a s s e i s m i c a l l y r e t r o f i t t e d p r i o r t o t h e t s u n a m i a n d e a r t h q u a k e . T h i s f a i l u r e w a s a s s u m e d t o b e c a u s e d b y t h e s e i s m i c m o t i o n s , w h i c h w e a k e n e d t h e s t r u c t u r e . T h e f o l l o w i n g t s u n a m i t h e n d a m a g e d t h e a d j a c e n t s p a n 3 a n d w a s h e d a w a y 8 s p a n s i n t o t a l ( J a p a n B r i d g e E n g i n e e r i n g C e n t e r 2 0 1 1 ) . M o s t o f t h e s p a n d a m a g e a n d u p l i f t w a s c a u s e d b y t h e d e f o r m a t i o n o f l a t e r a l s e i s m i c r e s t r a i n t s w h i c h f r e e d u p t h e s p a n s t o b e p u s h e d o f f t h e i r b e a r i n g . T h i s u n s e a t i n g w a s c a u s e d b y e i t h e r t h e t s u n a m i l a t e r a l f o r c e s o r j u s t b u o y a n t f o r c e s ( K a w a s h i m a 2 0 1 2 a n d J a p a n B r i d g e E n g i n e e r i n g C e n t e r 2 0 1 1 ) . T h e b r i d g e w a s r e t r o f i t t e d a f e w y e a r s b e f o r e t h e t s u n a m i , a n d c a b l e r e s t r a i n t s w e r e a d d e d b e t w e e n t h e s p a n s t h a t e v e n t u a l l y w a s h e d a w a y . S o m e o f t h e r e s t r a i n e r s r u p t u r e d , b u t o t h e r s s t a y e d i n t a c t , a n d t h e w a s h e d a w a y s p a n s w e r e f o u n d s t i l l c o n n e c t e d d o w n s t r e a m o f t h e f l o w ( K a w a s h i m a a n d M a t s u z a k i 2 0 1 2 ) . A v i d e o c a p t u r e d t h e U t a t s u b r i d g e b e i n g i n u n d a t e d b y t h e t s u n a m i . E v e n t u a l l y , t h e e n t i r e b r i d g e w a s e n g u l f e d i n t h e w a v e s ( F i g u r e C - 2 ) . F r o m t h e v i d e o , t h e f l o w v e l o c i t y w a s c a l c u l a t e d t o b e a b o u t 6 m / s ( K a w a s h i m a a n d M a t s u z a k i 2 0 1 2 ) . Figure C-4. Fuji Bridge Damage (Kawashima & Matsuzaki, 2012)

1 2 7C.2.3.3.7 Koizumi BridgeT h e K o i z u m i B r i d g e h a d b e e n s e i s m i c a l l y r e t r o f i t t e d w i t h h y d r a u l i c d a m p e r s a t t h e a b u t m e n t s b e f o r e t h e e v e n t . H o w e v e r , t h e s e e n h a n c e m e n t s c o u l d n o t w i t h s t a n d t h e i n u n d a t i o n b y t h e t s u n a m i , w h i c h w a s h e d a w a y a l l s i x s p a n s o f t h e b r i d g e . A s i t e i n v e s t i g a t i o n c o n d u c t e d r e v e a l e d t h a t m o s t o f t h e s p a n s w e r e l i f t e d o f f t h e i r p i e r s f r o m t h e u p w a r d f o r c e s p r o d u c e d b y t h e t s u n a m i . T h e l a t e r a l r e s t r a i n e r s f r o m s h e a r k e y s a n d d a m p e r s c o u l d n o t c o m p e t e w i t h t h e l a t e r a l t s u n a m i f o r c e s ; o n c e f r e e d f r o m l a t e r a l r e s t r a i n t , t h e s p a n s w e r e f l o a t e d a w a y f r o m t h e v e r t i c a l f o r c e s ( E E R I 2 0 1 1 ) . O n e o f t h e m a i n c h a n n e l p i e r s w a s w a s h e d a w a y a f t e r d e e p s c o u r w a s f o r m e d ( J a p a n B r i d g e E n g i n e e r i n g C e n t e r 2 0 1 1 ) . T o r e s t o r e t r a f f i c a n d p o s t - d i s a s t e r r e c o v e r y , a t e m p o r a r y s t r u c t u r e w a s b u i l t t o m o v e p e o p l e a n d g o o d s a f t e r t h e t s u n a m i ( F i g u r e C - 5 ) ( E E R I 2 0 1 1 ) . C.2.3.3.8 Nijyu-ichihama BridgeT h e t s u n a m i w a s h e d o u t t h e b a c k f i l l b e h i n d b o t h a b u t m e n t s , c a u s i n g t h e s i n g l e s p a n b r i d g e t o l o o k l i k e i t h a d t h r e e s p a n s ( E E R I 2 0 1 1 ) . E x t r e m e s c o u r i n g o c c u r r e d a t t h e p i e r s a s w e l l , a n d t h e s e w e r e l a t e r r e p a i r e d b y p o u r i n g n e w c o n c r e t e a r o u n d t h e d a m a g e d a n d e x p o s e d f o o t i n g s ( J a p a n B r i d g e E n g i n e e r i n g C e n t e r 2 0 1 1 ) . T o r e s t o r e t r a f f i c , t e m p o r a r y s t e e l I g i r d e r a p p r o a c h s p a n s w e r e s e t i n p l a c e , a n d t e m p o r a r y s t e e l t o w e r s w e r e a l s o e r e c t e d f o r a d d i t i o n a l s u p p o r t ( E E R I 2 0 1 1 ) . C.2.3.3.9 Kawahara River Bridge T h i s b r i d g e w a s s t r u c k b y a f l o a t i n g t w o - s t o r y b u i l d i n g , b u t s u r p r i s i n g l y o n l y s u f f e r e d m i n o r d a m a g e f r o m t h i s i m p a c t . M o s t o f t h e d a m a g e w a s c a u s e d b y t h e d r a m a t i c e r o s i o n o f t h e e m b a n k m e n t f i l l . A t e m p o r a r y b r i d g e w a s i n s t a l l e d a d j a c e n t t o t h e s t r u c t u r e ( K a w a s h i m a 2 0 1 1 ) .C.2.4 Rapid RestorationC.2.4.1 Temporary StructureA s d o c u m e n t e d a b o v e , t e m p o r a r y b r i d g e s w e r e d e p l o y e d i n s e v e r a l c a s e s t o a i d i n r e l i e f ( t h e K o i z u m i , N i j y u - i c h i h a m a , a n d K a w a h a r a b r i d g e s ) . P e r m a n e n t r e p a i r s o r r e p l a c e m e n t s w e r e i m p l e m e n t e d l a t e r .C.2.4.2 Permanent StructureR e p a i r e f f o r t s w e r e g e n e r a l l y v e r y q u i c k a c r o s s t h e n a t i o n . B y M a r c h 2 4 t h , a b o u t 9 4 % o f r e p a i r s h a d b e e n m a d e f o r s l i g h t t o m o d e r a t e d a m a g e ; r e s t o r a t i o n m e a s u r e s f o r e x t r e m e d a m a g e s w e r e c o m p l e t e d b y M a r c h 3 0 t h ( K a z a m a a n d N o d a 2 0 1 2 ) . J a p a n d o e s h a v e a g u i d e f o r r e p a i r i n g r e i n f o r c e d c o n c r e t e p i e r s b a s e d o n t h e d a m a g e s t a t e s ( D ) a n d d a m a g e d e g r e e a s s i g n e d d u r i n g t h e i n s p e c t i o n p e r i o d . A s i m p l e c h a r t i s u s e d t o d e t e r m i n e t h e b e s t r e c o m m e n d e d r e s t o r a t i o n p r o c e d u r e , w h i c h r a n g e s f r o m r e i n f o r c e d c o n c r e t e j a c k e t i n g , r e s i n i n j e c t i o n , a n d F R P ( S a i n i a n d S a i i d i 2 0 1 3 ) .Figure C-5. Koizumi Bridge Damage (Istrati et al. 2017, photo by E.V. Monzon)

1 2 8C.2.5 ChallengesI n i t i a l l y , t h e d e s t r u c t i o n f r o m t h e c o m b i n e d e a r t h q u a k e a n d t s u n a m i e v e n t s w a s s o w i d e s p r e a d . T h e r e f o r e , i t w a s d i f f i c u l t t o d e t e r m i n e w h e r e t o s t a r t d i s a s t e r r e l i e f e f f o r t s . F u r t h e r m o r e , s o m e s t r u c t u r e s r e q u i r e d a n i n - d e p t h a n a l y s i s t o d e t e r m i n e i f t h e d a m a g e w a s c a u s e d b y t h e e a r t h q u a k e o r t s u n a m i . T h i s i s i m p o r t a n t t o u n d e r s t a n d t h e r o b u s t n e s s o f t h e s e s t r u c t u r e s , a n d t o l e a r n i f p r e v i o u s r e t r o f i t s ( i f a p p l i c a b l e ) d i d s h o w i m p r o v e m e n t s t o d e s i g n a n d r e d u c e d t h e l e v e l o f d a m a g e . C.2.6 Innovations and Lessons Learned C.2.6.3 Elastomeric BearingsB r i d g e s t h a t u s e d e l a s t o m e r i c b e a r i n g s w e r e f o u n d t o b e l e s s l i k e l y t o s u f f e r e a r t h q u a k e m o t i o n d a m a g e , a s s h o w n i n F i g u r e C - 6 . B r i d g e s t h a t i n c l u d e d d a m p e r s o r o t h e r s e i s m i c f o r c e r e d u c i n g d e v i c e s a l s o t e n d e d t o p e r f o r m b e t t e r ( K a w a s h i m a 2 0 1 2 ) . T h e u s e o f e l a s t o m e r i c b e a r i n g s w a s i m p l e m e n t e d e x t e n s i v e l y a f t e r t h e 1 9 9 5 K o b e e a r t h q u a k e , a s t h e y a l s o t e n d e d t o p e r f o r m b e t t e r i n t h a t e a r t h q u a k e ( K a w a s h i m a 2 0 1 1 ) .C.2.6.4 Scour and Buoyancy Damage Mitigation S t r u c t u r e s t h a t w e r e t a l l e r t h a n t h e t s u n a m i w a v e s a n d s h o r t i n l e n g t h o u t p e r f o r m e d t h e i r c o u n t e r p a r t sw i t h o p p o s i t e d i m e n s i o n s . M o s t o f t h e d a m a g e c a u s e d b y t h e t s u n a m i w a v e s w a s e x t r e m e e r o s i o n o f e m b a n k m e n t s d u e t o l a c k o f s c o u r p r o t e c t i o n ( r i p r a p , e t c . ) . C o m m o n s c o u r c o u n t e r m e a s u r e s w o u l d h e l p m i t i g a t e s o m e o f t h e e f f e c t s o f e r o s i o n . T o p r e v e n t b u o y a n t f o r c e s f r o m c a u s i n g t h e u n s e a t i n g o f b r i d g e g i r d e r s , v e r t i c a l r e s t r a i n e r s a r e r e c o m m e n d e d f o r f u t u r e b r i d g e d e s i g n s ( K a w a s h i m a 2 0 1 2 ) . H o w e v e r , f o r s o m e o f t h e o l d e r b r i d g e s , t h e s u b s t r u c t u r e s m a y n e e d t o b e r e t r o f i t t e d t o w i t h s t a n d t h e u p w a r d f o r c e s g e n e r a t e d b y t h e e n g a g e d r e s t r a i n t s ( K a w a s h i m a a n d M a t s u z a k i 2 0 1 2 ) . T h e i m p a c t s o f h y d r a u l i c f o r c e s a r e s h o w n i n F i g u r e C - 7 . Figure C-6. Elastomeric Bridge No Damage (Kawashima & Matsuzaki 2012) Figure C-7. Typical Tsunami Damage (Kawashima & Matsuzaki 2012)

129 C.2.6.5 Deep Foundations Structures with deep foundations performed well in the tsunami. Scour of bents and abutments were not a major problem across the board, as these foundations are less vulnerable to scour. Most of the damage associated at these points was from the erosion of backfill (Kawashima 2011). C.2.6.6 Fiber Reinforced Polymer Fiber Reinforced Polymer (FRP) performed well in the earthquake and tsunami. Many bridges had been repaired and or retrofitted after previous earthquakes, and in most cases, hardly suffered damage in the 2011 earthquake.

1 3 0C.3 Nisqually 2001 [Earthquake] Table C-3. Nisqually EarthquakeCase Study Name/ Date Nisqually Earthquake (2001)L ocation Washington, USAEvent Type EarthquakeBridge Name Alaskan Way V iaduct Scope/ Costs V iaduct Replacement with Tunnel, estimated cost $ 3.1 billionPlanning Techniques/ Tools HAZ US and ShakeMapsEvent Response Immediate inspections of nearby structures following the earthquakeAssessment Techniques/ Tools ShakeMaps in combination with bridge age, type, and period to identify which bridges are more likely to have suffered damage, as well as traditional visual inspection techniques Rapid Restoration Type Immediate temporary shoring, permanent replacement with a tunnelInnovations • Using bridge characteristics and seismic spectral acceleration to triage structures post-earthquake• Replacement of structure with tunnel instead of bridgeC.3.1 IntroductionI n 2 0 0 1 , t h e N i s q u a l l y E a r t h q u a k e s t a r t l e d t h e m a j o r i t y o f W e s t e r n W a s h i n g t o n . T h e e p i c e n t e r w a s a b o u t 1 8 k m N E o f O l y m p i a a n d 5 7 k m S W o f S e a t t l e . I n t o t a l , 7 8 b r i d g e s w e r e d a m a g e d , b u t t h e m o s t a l a r m i n g d a m a g e w a s l o c a t e d o n t h e A l a s k a n W a y V i a d u c t ( R a n f e t a l . 2 0 0 7 ; F a r l e y 2 0 1 8 ) . T h e V i a d u c t w a s o r i g i n a l l y c o n s t r u c t e d i n 1 9 5 3 a n d w a s a p r o m i n e n t f e a t u r e a l o n g t h e S e a t t l e W a t e r f r o n t . T h e e x t e n t o f t h e d a m a g e w a s n o t d i s c o v e r e d u n t i l m o n t h s a f t e r t h e e a r t h q u a k e , i g n i t i n g a f i e r c e r e p l a c e m e n t c a m p a i g n a m o n g r e s e a r c h e r s a n d e n g i n e e r s . C o n c e r n s a b o u t t h e b r i d g e ’ s s t r u c t u r a l i n t e g r i t y d a t e d b a c k t o t h e L o m a P r i e t a E a r t h q u a k e i n 1 9 8 9 , b u t i t w a s n o t u n t i l t h e 2 0 0 1 N i s q u a l l y E a r t h q u a k e t h a t s t e p s w e r e t a k e n t o a d d r e s s t h e s e c o n c e r n s ( F a r l e y 2 0 1 8 ) . F i g u r e C - 8 s h o w s t h e V i a d u c t p r i o r t o r e m o v a l . I n a d d i t i o n t o d a m a g e t o t h e A l a s k a n W a y V i a d u c t , r e s e a r c h e r s l o o k e d f o r a m e t h o d t o p r i o r i t i z e b r i d g e i n s p e c t i o n s a f t e r t h e N i s q u a l l y E a r t h q u a k e . R e s e a r c h e r s d e t e r m i n e d t h a t a c o m b i n a t i o n o f t h e s p e c t r a l a c c e l e r a t i o n , y e a r o f c o n s t r u c t i o n , a n d b r i d g e t y p e w e r e t h e f a c t o r s n e e d e d t o i d e n t i f y w h i c h b r i d g e s s h o u l d b e p r i o r i t i z e d p o s t - e a r t h q u a k e . T h e s e t h r e e f a c t o r s c o r r e l a t e d t o t h e s t r u c t u r e s t h a t h a d t h e m o s t d a m a g e w h e n c o m p a r e d t o t h e m a p o f a c t u a l d a m a g e d b r i d g e s , d e m o n s t r a t i n g t h e v a l i d i t y o f t h i s a p p r o a c h ( R a n f e t a l . 2 0 0 7 ) . C.3.1.1 Event Response D u r i n g t h e N i s q u a l l y E a r t h q u a k e , i n s p e c t o r s w e r e d e p l o y e d b a s e d o n e p i c e n t r a l d i s t a n c e a n d r e p o r t s o f o b s e r v e d d a m a g e . T h i s r e q u i r e d h u n d r e d s o f b r i d g e s t o b e i n s p e c t e d i m m e d i a t e l y f o l l o w i n g t h e e a r t h q u a k e , Figure C-8. Alaskan Way Viaduct (Washington State Department of Transportation 2020)

131 using time, money, and resources. Post-earthquake, the value of pre-inspection triage was found, and researchers began developing ways to better categorize and determine the order of inspections (Ranf et al. 2007). Structures such as the Alaskan Way Viaduct were inspected at this time, however noticeable damage did not appear until months after the earthquake (Farley 2018). C.3.2 Emergency Planning In 1989, the Loma Prieta Earthquake in California caused the Cypress Freeway to collapse, a structure with a very similar design to the Alaskan Way Viaduct. This collapse worried many researchers at the time and led to an in-house review of the Viaduct. This review confirmed many similarities between the structures (Farley 2018). Moreover, the University of Washington conducted several seismic vulnerabilities studies in 1995 investigating the Viaduct to determine the limits of the structure during another seismic event, and up to what magnitude of earthquake the structure could withstand. However, these studies did not lead to major discussions on repairs or replacements until the 2001 Nisqually Earthquake (PB & Jacobs 2007). C.3.2.1 Crowdsourcing and Information Gathering To better understand the magnitude of the Nisqually Earthquake, researchers associated with the Pacific Northwest Seismograph Network (PNSN) studied information from ShakeMaps, a compilation of data from geologic statistics and strong-motion stations. In regions between data collecting sites, interpolation was used to fill in the map. During the Nisqually earthquake, 42 PNSN stations collected data on the earthquake, and this was used to generate the maps. Another platform used for gathering information was HAZUS, a program which uses fragility relationships for a particular bridge based on span length, continuity, material type, and year built. HAZUS is used to analyze the probability of damage caused by an earthquake, and these likelihoods can be used to pre-plan which bridges should be inspected first, based on these characteristics. HAZUS models were used as a comparison to a prioritization method developed in a research project by the University of Washington. The project examined post-earthquake data from the Nisqually Earthquake to determine the viability of bridge characteristics-based structure prioritization to determine if the structures given a higher priority based on specific characteristics, such as type, age, and ground acceleration, matched with this pre-established system. Further discussion on the use of HAZUS and bridge prioritization can be found in the Innovations and Lessons Learned section (Ranf et al. 2007).

1 3 2C.3.3 AssessmentT h e A l a s k a n W a y V i a d u c t w a s i n i t i a l l y i n s p e c t e d i m m e d i a t e l y f o l l o w i n g t h e E a r t h q u a k e i n F e b r u a r y o f 2 0 0 1 . D u r i n g t h i s i n s p e c t i o n , t h e r e w e r e n o c o n c e r n s a b o u t t h e b r i d g e ’ s s t r u c t u r a l i n t e g r i t y . H o w e v e r , i n A p r i l o f t h a t s a m e y e a r , c r a c k s w e r e f o u n d n e a r t h e s t r u c t u r e ’ s j o i n t s a t t h e c o n n e c t i o n s b e t w e e n t h e d e c k s a n d c o l u m n s , a s s h o w n i n F i g u r e C - 9 . T h e s e c r a c k s w e r e a t t r i b u t e d t o l i q u e f a c t i o n o f t h e s u r r o u n d i n g s o i l . T h e i n a d e q u a t e s o i l b e l o w t h e b r i d g e w a s e s t i m a t e d t o b e 3 0 f e e t d e e p i n s o m e r e g i o n s , a n d c o n s i s t e d o f l o s e s o i l , s a w d u s t , a n d r u b b l e . M o r e a l a r m i n g , t h e s o i l w a s h e l d u p b y a n a g i n g w o o d e n s e a w a l l . T h i s d i s c o v e r y a c c e l e r a t e d t h e n e e d f o r a s t r u c t u r e r e p l a c e m e n t , a s t h e t h r e a t o f t h e C a s c a d i a S u b d u c t i o n Z o n e e a r t h q u a k e w o r r i e d e n g i n e e r s ( F a r l e y 2 0 1 8 ) . A n a d d i t i o n a l s t r u c t u r a l a s s e s s m e n t w a s l a t e r c o n d u c t e d a n d f o u n d t h a t t h e N i s q u a l l y E a r t h q u a k e h a d w e a k e n e d t h e c o n n e c t i o n s b e t w e e n t h e c o l u m n s a n d d e c k s . F u r t h e r m o r e , i t i d e n t i f i e d f o u n d a t i o n p r o b l e m s d u e t o s h i f t i n g o f t h e s t r u c t u r e , w h i c h w a s c o m p o u n d e d w i t h c r a c k s . T h e s t r u c t u r e c o n t i n u e d t o s h i f t e v e n y e a r s a f t e r t h e e a r t h q u a k e . B y 2 0 0 9 , t h e c o l u m n s h a d s e t t l e d a n e s t i m a t e d 1 . 5 t o 5 . 5 i n c h e s , d e p e n d i n g o n t h e l o c a t i o n ( O t t 2 0 1 1 ) . A d d i t i o n a l l y , t h e W a s h i n g t o n D O T c o m m i s s i o n e d t h e S t r u c t u r a l S u f f i c i e n c y R e v i e w C o m m i t t e e ( S S R C ) t o t a k e a n o t h e r l o o k a t t h e V i a d u c t ’ s s t r u c t u r a l i n t e g r i t y . T h e f i n d i n g s f o u n d t h a t t h e s t r u c t u r e w o u l d b e s e v e r e l y d a m a g e d w i t h r e t u r n p e r i o d s o f o n l y 1 0 8 y e a r s . T h i s l e d t o h e i g h t e n e d e f f o r t s f o r t o t a l r e p l a c e m e n t ( P B & J a c o b s 2 0 0 7 ) . C.3.4 Rapid RestorationC.3.4.1 Contracting A f t e r t h e N i s q u a l l y E a r t h q u a k e , a r e p l a c e m e n t o f t h e A l a s k a n W a y V i a d u c t w a s d e t e r m i n e d t o b e t h e b e s t o p t i o n . T h e 2 0 0 1 S S R C f i n d i n g s d e t e r m i n e d t h e s e a w a l l h o l d i n g b a c k t h e s o i l s u p p o r t i n g t h e V i a d u c t a n d t h e s t r u c t u r e o f t h e V i a d u c t i t s e l f w e r e p r o n e t o c o l l a p s e i n t h e e v e n t o f a n o t h e r , e s p e c i a l l y l a r g e r , e a r t h q u a k e . T h i s s p a r k e d t h e A l a s k a n W a y V i a d u c t a n d S e a w a l l R e p l a c e m e n t P r o j e c t ( A W V S R P ) . I d e a s r a n g e d f r o m a n e w v i a d u c t , a t u n n e l , a n d a c o m b i n a t i o n o f b o t h . U l t i m a t e l y , a t u n n e l w a s d e c i d e d o n a s t h e r e p l a c e m e n t o p t i o n , a s i t w a s d e e m e d t o b e s a f e r t h a n a n e w b r i d g e w i t h t h e t h r e a t o f a m a j o r s u b d u c t i o n z o n e e a r t h q u a k e ( F i g u r e C - 1 0 ) . F u r t h e r m o r e , o t h e r m a j o r c i t i e s h a d a l r e a d y t a k e n s i m i l a r a c t i o n t o d e m o l i s h t h e i r e x i s t i n g e l e v a t e d h i g h w a y s a n d s a w b e n e f i t s t o o t h e r a l t e r n a t i v e s r a t h e r t h a n r e p l a c i n g t h e m w i t h n e w e l e v a t e d s t r u c t u r e s . C o n s i d e r a t i o n s t o w a r d t h e f i n a l d e c i s i o n a l s o i n c l u d e d i m p a c t t o u t i l i t i e s , b u s i n e s s e s , a n d m o t o r i s t s . T h e d e c i s i o n e v e n w e n t t o t h e S t a t e o f W a s h i n g t o n L e g i s l a t u r e . I t w a s n o t u n t i l 2 0 0 8 w h e n t h e f i n a l t u n n e l d e c i s i o n w a s m a d e a f t e r y e a r s o f b a c k a n d f o r t h b e t w e e n k e y s t a k e h o l d e r s ( O t t 2 0 1 1 ) . Figure C-10. Tunnel Construction (Washington State Department of Transportation 2020) Figure C-9. Cracks from Continued Column Settling (Lindblom 2014)

1 3 3C.3.4.2 DesignT h e t u n n e l c o n s i s t e d o f a d e e p - b o r e d e s i g n h y b r i d .T h e e s t i m a t e d c o s t f o r t h e r e p l a c e m e n t w a s $ 3 0 0m i l l i o n . T h e p r o j e c t w a s f i n a l l y a p p r o v e d b y t h e F H W Ai n 2 0 1 1 , a n d d e m o l i t i o n s t a r t e d l a t e r t h a t y e a r ( O t t2 0 1 1 ) .C.3.4.3 Temporary StructureT h e A l a s k a n W a y V i a d u c t w a s i n t e r m i t t e n t l y c l o s e da f t e r t h e A p r i l 2 0 0 1 d i s c o v e r y o f c r a c k s t o i n s t a l ls h o r i n g a n d o t h e r t e m p o r a r y s u p p o r t s . A s t h e s t r u c t u r ec o n t i n u e d t o s h i f t y e a r s a f t e r , W S D O T i n s t a l l e da d d i t i o n a l r e i n f o r c e m e n t s i n t h e c o l u m n s a n d i m p o s e dw e i g h t l i m i t s o n t h e b r i d g e ( O t t 2 0 1 1 ) . E x a m p l e s o f t h et e m p o r a r y s u p p o r t d e p l o y e d a r e s h o w n i n F i g u r e C - 1 1 .T h e s e s u p p o r t s r e m a i n e d i n p l a c e u n t i l t h e b r i d g e w a sr e m o v e d .C.3.4.4 Permanent StructureD e m o l i t i o n o f t h e V i a d u c t b e g a n i n 2 0 1 1 ( F i g u r e C - 1 2 ) a n d w a s c o m p l e t e d i n 2 0 1 9 . T h e n e w d o u b l e -d e c k t u n n e l t o t a l e d o v e r 9 2 0 0 f e e t i n l e n g t h . T u n n e l b o r i n g o p e r a t i o n s b e g a n a t t h e e n d o f 2 0 1 5 a n dc o n t i n u e d u n t i l e a r l y 2 0 1 7 ( O t t 2 0 1 1 ) .C.3.5 ChallengesW i t h t h e A l a s k a n W a y V i a d u c t , t h e l i q u e f i a b l e s o i l s u p p o r t i n g t h e b r i d g e c r e a t e d m a n y c h a l l e n g e s . T h ec h a n g e s t o t h e s o i l c o n t i n u e d t o c r e a t e c r a c k s i n t h e s t r u c t u r e y e a r s a f t e r t h e 2 0 0 1 N i s q u a l l y E a r t h q u a k e .F u r t h e r m o r e , t h e s o i l w a s s u p p o r t e d b y a n a g i n g s e a w a l l . T h e V i a d u c t w a s d e t e r m i n e d t o b e o n “ b o r r o w e d ”t i m e ( W a s h i n g t o n S t a t e D e p a r t m e n t o f T r a n s p o r t a t i o n 2 0 1 9 ) .Figure C-12. Removal of Alaskan Way Viaduct (Washington State Department of Transportation 2018) Figure C-11. Temporary Supports After Nisqually Earthquake (Photo by Erik Stuhaug, Courtesy Seattle Municipal Archives (113883))

1 3 4A d d i t i o n a l l y , t h e d e c i s i o n t o r e p l a c e t h e s t r u c t u r e w i t h a t u n n e l w a s n o t e a s y . T h e r e w e r e m i x e d o p i n i o n so n w h a t t o d o w i t h t h e s t r u c t u r e . S o m e e n v i r o n m e n t a l g r o u p s a r g u e d f o r t h e d e m o l i t i o n w i t h o u t a n yr e p l a c e m e n t . A s t u d y w a s c o n d u c t e d w i t h t h a t s c e n a r i o , a n d f o u n d t h a t S e a t t l e w o u l d b e i n g r i d l o c k , c a u s i n ga f u l l c i t y s h u t d o w n . T h i s i d e a w a s q u i c k l y v e t o e d d e s p i t e p u s h e s f r o m t h e g r o u p s ( O t t 2 0 1 1 ) . D e s p i t e t h e s ec h a l l e n g e s , t h e r e m o v a l o f t h e i c o n i c s t r u c t u r e p a v e d t h e w a y t o a n e w W a t e r f r o n t , a s s h o w n i n F i g u r e C -1 3 .A n o t h e r c h a l l e n g e r e l a t e d t o p r i o r i t i z i n g b r i d g e a s s e s s m e n t s a f t e r a n e a r t h q u a k e . W h e n c o n s i d e r i n gb r i d g e t r i a g e , i t w a s u n c l e a r i f b r i d g e l e n g t h o r o t h e r c h a r a c t e r i s t i c s c o r r e l a t e d t o b r i d g e d a m a g e . M o s t o ft h e s t r u c t u r e s d a m a g e d b y t h e N i s q u a l l y E a r t h q u a k e w e r e a p p r o x i m a t e l y t h e s a m e l e n g t h , s o i t w a s n o tf e a s i b l e t o i d e n t i f y a c o r r e l a t i o n . M o r e o v e r , s k e w , t y p e o f s p a n ( c o n t i n u o u s v s . s i m p l y s u p p o r t e d ) w e r e n o tm e t r i c s c o n s i d e r e d a t t h e t i m e , a n d t h e s e c o u l d p l a y a r o l e w i t h t h e l i k e l i h o o d o f d a m a g e . T h e r e h a s n o tb e e n a m a j o r e a r t h q u a k e i n W a s h i n g t o n s i n c e t h i s m e t r i c w a s d e v e l o p e d , s o i t i s n o t p o s s i b l e t o t e s t t h el e g i t i m a c y o f t h e f r a g i l i t y c u r v e s d e v e l o p e d . H o w e v e r , r e s e a r c h e r s d i d a p p l y t h e s e c u r v e s t o s m a l l e r , l e s sd e s t r u c t i v e e a r t h q u a k e s w i t h p o s i t i v e r e s u l t s .C.3.6 Innovations and Lessons LearnedC.3.6.1 Development of a Post-Earthquake Assessment MetricW i t h o u t d e v e l o p i n g a m e t r i c t o d e c r e a s e t h e t o t a l n u m b e r o f b r i d g e s t h a t r e q u i r e i m m e d i a t e i n s p e c t i o np o s t - e a r t h q u a k e , D O T s w i l l b e o v e r w h e l m e d w i t h t h e q u a n t i t y o f s t r u c t u r e s t h a t n e e d t o b e a c c e s s e d .F u r t h e r m o r e , m a n y o f t h e b r i d g e s t h a t a r e f l a g g e d f o r i n s p e c t i o n b a s e d o n t h i s s t a n d a r d d i d n o t s u f f e r a n yd a m a g e . U s i n g a m e t r i c s i m i l a r t o t h e f r a g i l i t y c u r v e s d e v e l o p e d c a n s a v e t i m e , m o n e y , a n d r e s o u r c e s f o rt h e D O T s . O n c e i n i t i a l i n s p e c t i o n s a r e c o m p l e t e , t h e r e m a i n i n g b r i d g e s w i t h i n t h e s p e c i f i e d e p i c e n t r a ld i s t a n c e c a n t h e n b e i n s p e c t e d t o i d e n t i f y a n y s t r u c t u r e s t h a t m a y h a v e b e e n i n a c c u r a t e l y c a t e g o r i z e d .W i t h o u t a n o t h e r m a j o r e a r t h q u a k e t o t e s t t h i s m e t r i c , i t i s d i f f i c u l t t o d e t e r m i n e t h e v a l i d i t y o f t h e s y s t e m ,b u t c o m p a r i s o n s t o s m a l l e r e a r t h q u a k e s h a v e b e e n p r o m i s i n g , a n d t h i s t a c t i c s h o u l d n o t b e r u l e d o u t f o rf u t u r e e v e n t s .Figure C-13. Before and After of Alaskan Way Viaduct Removal (Washington State Department of Transportation 2019)

1 3 5F o r o t h e r s t r u c t u r e s i n t h e S e a t t l e a r e a , d a t af r o m S h a k e M a p s w a s u s e d t o f i n d a n yc o r r e l a t i o n b e t w e e n t h e b r i d g e s t h a t w e r ed a m a g e d i n t h e N i s q u a l l y E a r t h q u a k e , a ss h o w n i n F i g u r e C - 1 4 . G e n e r a l l y , s t r u c t u r e sc l o s e s t t o t h e e p i c e n t e r d i d h a v e h i g h e r l e v e l so f d a m a g e , b u t b r i d g e s 3 0 - 4 5 k m a w a y d i d n o ta n d o n e s 4 5 - 6 0 k m a w a y d i d – t h e c h a n g e i na f f e c t e d b r i d g e s d i d n o t d i r e c t l y c o r r e l a t e t od i s t a n c e . H o w e v e r , w h e n t h e s p e c t r a la c c e l e r a t i o n w a s c o n s i d e r e d , t h e r e s u l t sb e c a m e c l e a r ; s t r u c t u r e s l o c a t e d i n t h e 0 . 3 ss p e c t r a l a c c e l e r a t i o n r a n g e h a d h i g h e r r a t e s o fd a m a g e . T h i s c o r r e l a t i o n m a k e s s e n s e , a s m o s to f t h e b r i d g e s d a m a g e d w e r e s h o r t e r i n l e n g t ha n d h a d a p e r i o d o f a b o u t 0 . 3 s . T h u s ,r e s o n a n c e w a s m o r e l i k e l y t o o c c u r a t t h el o c a t i o n s , a n d t h e r e f o r e , m o r e d a m a g e d w a si n c u r r e d ( R a n f e t a l . 2 0 0 7 ) .F u r t h e r m o r e , t h e a g e o f t h e b r i d g e a n d t h et y p e o f s t r u c t u r e w e r e f o u n d t o c o r r e l a t e w i t hd a m a g e . M o v a b l e b r i d g e s a n d t r u s s e s h a d t h eh i g h e s t l e v e l s o f d a m a g e . S t r u c t u r e s b u i l t a f t e r 1 9 7 5 p e r f o r m e d m u c h b e t t e r , w h i c h i s l i n k e d t o t h e a d d i t i o no f s e i s m i c c o d e p r o v i s i o n s a f t e r t h e S a n F e r n a n d o E a r t h q u a k e i n 1 9 7 1 ( R a n f e t a l . 2 0 0 7 ) .T h e a c t u a l p e r f o r m a n c e o f b r i d g e s d u r i n g t h e N i s q u a l l y e a r t h q u a k e w e r e c o m p a r e d t o t h e H A Z U Sp r e d i c t i o n s , a n d t h e r e s u l t s v a r i e d w i t h n o s t r o n g c o r r e l a t i o n . I n f a c t , H A Z U S g r o s s l y o v e r e s t i m a t e d t h ed a m a g e f o r s o m e c a t e g o r i e s w h i l e u n d e r e s t i m a t i n g o t h e r s . N e w f r a g i l i t y c u r v e s w e r e d e v e l o p e d b a s e d o nt h e N i s q u a l l y E a r t h q u a k e d a t a , w h i c h w e r e m o r e a c c u r a t e c o m p a r e d t o t h e H A Z U S f r a g i l i t y c u r v e s . T h en e w c u r v e s a r e t h o u g h t t o b e t t e r r e p r e s e n t t h e g e o l o g i c c o n d i t i o n s o f t h e P a c i f i c N o r t h w e s t ( R a n f e t a l .2 0 0 7 ) .C.3.6.2 Replacement Does Not Always Mean BridgeT h e d e c i s i o n t o r e p l a c e t h e A l a s k a n W a y V i a d u c t w i t h a t u n n e l h a d b r o a d r a n g i n g i m p l i c a t i o n s . W i t hr a p i d l y g r o w i n g m e t r o p o l i t a n a r e a s , r e a l e s t a t e p r i c e s h a v e r i s e n r a p i d l y , a n d u s e s f o r t h e r e m a i n i n g p a r c e l sa r e t a r g e t e d f o r b u i l d i n g d e v e l o p m e n t s , r a t h e r t h a n e x p a n d i n g t r a n s p o r t a t i o n s y s t e m s . T h e u s e o f t u n n e l s i sa g r o w i n g i d e a f o r c r o w d e d c i t i e s , a n d p r o v i d e s s a f e r a l t e r n a t i v e s t o b r i d g e s , e s p e c i a l l y i n h i g h - s e i s m i ca r e a s . T u n n e l s a r e m o r e f l e x i b l e a n d c a n m o v e w i t h t h e g r o u n d m o t i o n s . A l t h o u g h t i m e c o n s u m i n g a n de x p e n s i v e , t u n n e l s c a n b e a v i a b l e a l t e r n a t i v e t o t r a d i t i o n a l b r i d g e d e s i g n s ( W a s h i n g t o n S t a t e D e p a r t m e n to f T r a n s p o r t a t i o n 2 0 1 9 ) .Figure C-14. ShakeMaps with Spectral Acceleration of 0.3s (Ranf et al. 2007)

1 3 6C.4 Northridge 1994 [Earthquake]Table C-4. Northridge EarthquakeCase Study Name/ Date Northridge Earthquake (1994)L ocation California, USAEvent Type EarthquakeBridge Name No specific bridge selected for this Case StudyScope/ Costs 6 bridges failed and 4 replacedPlanning Techniques/ Tools HAZ US Prediction ModelsEvent Response N/ AAssessment Techniques/ Tools HAZ US and REDARSRapid Restoration Type CFRP and GFRP column and wall jacketingInnovations • V isual Assessment Catalog, HAZ US, and REDARS• Inspection team training• Emergency Contracts before event• Importance of retrofitsC.4.1 IntroductionO n J a n u a r y 1 7 t h , 1 9 9 4 , t h e N o r t h r i d g e E a r t h q u a k er e a c h e d a m a g n i t u d e o f 6 . 7 o n t h e R i c h t e r s c a l e n e a r t h eS a n F e r n a n d o V a l l e y i n C a l i f o r n i a . T h e i n i t i a l s h o c kl a s t e d n l y t w e n t y s e c o n d s , b u t t h e d a m a g e t oi n f r a s t r u c t u r e r e s u l t e d i n t h e d e a t h s o f f i f t y - s e v e n p e o p l e( C o o p e r 1 9 9 4 ) . O u t o f t h e 2 , 0 0 0 b r i d g e s n e a r t h ee p i c e n t e r , s i x f a i l e d a n d f o u r w e r e s o h e a v i l y d a m a g e dt h e y h a d t o b e r e p l a c e d ( A l i p o u r 2 0 1 6 ) . F i g u r e C - 1 5s h o w s a n e x a m p l e o f d a m a g e c a u s e d b y t h e e a r t h q u a k e .C.4.1.1 Event ResponseI n r e s p o n s e t o t h e N o r t h r i d g e E a r t h q u a k e i n 1 9 9 4 , t h eC a l i f o r n i a D e p a r t m e n t o f T r a n s p o r t a t i o n ( C a l t r a n s ) m o b i l i z e d t h r e e t e a m s o f b r i d g e i n s p e c t o r s i m m e d i a t e l yf o l l o w i n g t h e e a r t h q u a k e . T h e s e t h r e e t e a m s o f i n s p e c t o r s w e r e s p e c i a l l y t r a i n e d i n b r i d g e a s s e s s m e n ta n d w e r e o n t h e g r o u n d w i t h i n t h r e e d a y s f o l l o w i n g t h ee v e n t . T h e u r g e n c y i n a s s e s s i n g a n d c a t e g o r i z i n g b r i d g e d a m a g e c o n t r i b u t e d t o t h e r a p i d r e s p o n s e a n d r e p a i ro f b r i d g e s f o l l o w i n g t h e N o r t h r i d g e E a r t h q u a k e ( C a l t r a n s 2 0 0 1 ) .C.4.2 Emergency PlanningC.4.2.1 Crowdsourcing and Information GatheringM u c h o f t h e c r o w d s o u r c i n g d a t a r e l a t e d t o t h i s e v e n t i s o u t d a t e d d u e t o t h e a m o u n t o f t i m e p a s s e d s i n c et h e e v e n t o c c u r r e d . T h e i n f o r m a t i o n g a t h e r i n g t e c h n i q u e s w e r e t h u s n o t e x p l o r e d f o r t h i s C a s e S t u d y .Figure C-15. Collapsed Elevated Freeway Caused by Northridge Earthquake (Buckle 1994, Photos courtesy of NCREER/MCEER Reports with support from the Federal Government via NSF)

1 3 7C.4.3 AssessmentA f e w h o u r s f o l l o w i n g t h e e a r t h q u a k e , t h r e e P o s t E a r t h q u a k e I n v e s t i g a t i o n T e a m s ( P E Q I T s ) w e r e s e n to f f t o i n v e s t i g a t e t h e d a m a g e s c a u s e d b y t h e N o r t h r i d g e E a r t h q u a k e . O n e t e a m w a s a s s i g n e d t h e S a n t aM o n i c a F r e e w a y , I - 1 0 , a n o t h e r t h e 1 1 8 / 4 0 5 i n t e r c h a n g e i n O r a n g e C o u n t y , a n d t h e t h i r d t o t h e G a v i nC a n y o n U n d e r c r o s s i n g c o l l a p s e a n d 1 4 / 5 i n t e r c h a n g e . O v e r a l l , t h e s e t h r e e t e a m s c o m p l e t e d f o r t y b r i d g ei n s p e c t i o n s o v e r t h e c o u r s e o f f i v e d a y s .T y p i c a l d a m a g e f r o m t h e N o r t h r i d g e e a r t h q u a k e i n c l u d e d s p a l l i n g a n d c r a c k i n g o f c o n c r e t e a b u t m e n t s ,s e t t l e m e n t o f a p p r o a c h s l a b s , t i p p i n g , o r d i s p l a c e m e n t o f b e a r i n g s , a n d s p a l l i n g o f c o l u m n c o n c r e t e c o v e r ,a s s h o w n i n F i g u r e C - 1 6 . M o s t o f t h e b r i d g e s i m p a c t e dw e r e b u i l t b e f o r e 1 9 7 1 w h e n m o r e s t r i n g e n t b r i d g es e i s m i c s t a n d a r d s w e r e i n t r o d u c e d , b u t s o m e b r i d g e sb u i l t a f t e r 1 9 7 1 a l s o e x p e r i e n c e d m i n o r d a m a g e . B r i d g es t r u c t u r e s i n N o r t h r i d g e b u i l t a f t e r 1 9 7 1 w i t h m o r es t r i n g e n t s e i s m i c s t a n d a r d s e x p e r i e n c e d m i n o r d a m a g et h a t w a s e a s i l y r e p a i r e d ( C o o p e r 1 9 9 4 ) . A s s e s s m e n t o fb r i d g e d a m a g e d e t e r m i n e d t h a t t h e l e v e l o f d a m a g e w a sf o u n d t o c o r r e l a t e w i t h b r i d g e s k e w , a b u t m e n t a n d p i e rt y p e , a n d s p a n c o n t i n u i t y . M o r e o v e r , r e i n f o r c e dc o n c r e t e b r i d g e s s a w t h e m o s t d a m a g e o v e r a l l , m a n y o fw h i c h h a d s h o r t c o l u m n s w i t h l i m i t e d a m o u n t s o ft r a n s v e r s e s t e e l l e a d i n g t o s h e a r f a i l u r e s ( M a r s h e t a l .2 0 1 3 ) .G r o u n d m o t i o n s f o r t h e s e s i t e s w e r e g a t h e r e d f r o mt h e C a l i f o r n i a S t r o n g M o t i o n I n s t r u m e n t a t i o n P r o g r a mf i e l d s e n s o r s t o b e t t e r u n d e r s t a n d t h e s e i s m i c l o a d sc a u s e d b y t h e e a r t h q u a k e . P r o g r a m e s t i m a t i o n sd e t e r m i n e d t h a t 1 , 6 0 0 b r i d g e s e x p e r i e n c e d s i g n i f i c a n td a m a g e f r o m t h e N o r t h r i d g e E a r t h q u a k e b a s e d o n t h eg r o u n d m o t i o n d a t a . S i x t y o f t h e s e i d e n t i f i e d b r i d g e sh a d r e c e n t l y b e e n r e t r o f i t t e d f o l l o w i n g t h e 1 9 8 7W h i t t i e r E a r t h q u a k e . B r i d g e s t h a t h a d b e e n r e t r o f i t t e du s i n g h i n g e o r j o i n t r e s t r a i n e r s a n d c o l u m n j a c k e t sp e r f o r m e d w e l l i n t h e e a r t h q u a k e ( C o o p e r 1 9 9 4 ) . T h eb r i d g e s t h a t h a d n o t b e e n r e t r o f i t t e d e x p e r i e n c e d t h em o s t d a m a g e , a n d i n s o m e c a s e s , c o l l a p s e d . B r i d g e sr e t r o f i t t e d w i t h r e s t r a i n e r s , e v e n t h o u g h t h e y d i d n o tm e e t c u r r e n t s t a n d a r d s , a v o i d e d s e v e r e d a m a g e , a n d p e r f o r m e d q u i t e w e l l ( W a r r i c k e t a l . 1 9 9 6 ) .C.4.4 Rapid RestorationC.4.4.1 Permanent StructureI n r e s p o n s e t o t h e e a r t h q u a k e e v e n t , t h e f i r s t s t e p t o r e s t o r i n g d a m a g e d b r i d g e s i n N o r t h r i d g e c o n s i s t e do f i d e n t i f y i n g a n d r a n k i n g b r i d g e s i n o r d e r o f r e t r o f i t p r i o r i t y . T o r e p a i r e x i s t i n g b r i d g e s w i t h d a m a g e dc o l u m n s , t h e s e a t w i d t h o f t h e c o l u m n s a n d p i e r s w e r e e x t e n d e d , o r c a b l e r e s t r a i n e r s w e r e a d d e d a c r o s s t h ej o i n t s . A d d i t i o n a l l y , o l d o r i n a d e q u a t e b e a r i n g s w e r e r e p l a c e d , a n d e x p a n s i o n j o i n t s e l i m i n a t e d . R e s t o r a t i o np r a c t i c e s a l s o i n v o l v e d f o o t i n g o v e r l a y s o r e x t e n s i o n s o f f o o t i n g r e t r o f i t s , s t r e n g t h e n i n g o f c a p b e a m s ,u t i l i z a t i o n o f v a r i o u s i s o l a t i o n t e c h n o l o g y , a n d w h e n p o s s i b l e , t h e u s e o f s i n g l e , c o n t i n u o u s s p a n r a t h e r t h a nm u l t i p l e s i m p l e s p a n s ( C o o p e r e t a l . 1 9 9 4 ) .Figure C-16. Typical Column Spalling Damage (Marsh & Stringer 2013)

1 3 8R e s t o r a t i o n p r a c t i c e s i m p l e m e n t e d f o l l o w i n g t h eN o r t h r i d g e E a r t h q u a k e i n c l u d e d j a c k e t i n g d a m a g e dc o l u m n s a n d f i l l i n g c r a c k s . F u l l h e i g h t c a r b o n a n d g l a s sf i b e r r e i n f o r c e d p o l y m e r ( C F R P & G F R P ) w r a p s w e r eu s e d t o j a c k e t r e i n f o r c e d c o n c r e t e c o l u m n s . D a m a g e dc o n c r e t e w a s r e p a i r e d u s i n g h i g h s t r e n g t h m o r t a r a n dl a p - w e l d i n g o f f r a c t u r e d r e i n f o r c e m e n t s t o o k p l a c e i nt h e p l a s t i c h i n g e r e g i o n . O p e n d i a g o n a l c r a c k s w e r ef i l l e d w i t h e p o x y i n j e c t i o n s t h r o u g h o u t t h e p o r t st h r o u g h t h e j a c k e t s . C F R P s t r i p s w e r e p l a c e d a t t h e w a l le d g e s t o i m p r o v e s h e a r a n d f l e x u r a l c a p a c i t y o f e x i s t i n gb r i d g e s f o l l o w i n g t h e e a r t h q u a k e . G F R P j a c k e t s w e r ea l s o u s e d t o w r a p w a l l s a s a r e t r o f i t t e c h n i q u e o nN o r t h r i d g e b r i d g e s f o l l o w i n g t h e e a r t h q u a k e ( S a i n i e ta l . 2 0 1 3 ) . C a l t r a n s e n g i n e e r s f a c e d a v a r i e t y o f d a m a g et y p e s w h e n a s s e s s i n g a n d r e p a i r i n g b r i d g e s a f f e c t e d b yt h e N o r t h r i d g e E a r t h q u a k e , a s s h o w n i n F i g u r e C - 1 7 .C.4.5 ChallengesB r i d g e s w i t h h i g h s k e w s a n d a t y p i c a l g e o m e t r i e s e x p e r i e n c e d g r e a t e r l e v e l s o f d a m a g e a n d d i d n o tp e r f o r m c o n s i s t e n t l y a c r o s s t h e b o a r d . C a l t r a n s b r i d g e e n g i n e e r s h a d d i f f i c u l t y d e v e l o p i n g b l a n k e t r e p a i rm e t h o d s o r d e s i g n r e t r o f i t s t h a t w o r k a c r o s s m u l t i p l e b r i d g e t y p e s ( C o o p e r 1 9 9 4 ) .O l d e r b r i d g e s b u i l t d u r i n g t h e 1 9 7 0 s a l s o h a d m i x e d p e r f o r m a n c e r e v i e w s . T h i s w a s b e c a u s e n e w e rs e i s m i c s t a n d a r d s w e r e j u s t s t a r t i n g t o b e i m p l e m e n t e d , a n d i t t o o k a b o u t a d e c a d e o f a d j u s t m e n t s b e f o r ed e s i g n s s h o w e d d r a m a t i c i m p r o v e m e n t s . D u e t o t h e v a r i a t i o n i n b r i d g e d e s i g n a n d p e r f o r m a n c e o v e r t i m e ,i t i s d i f f i c u l t t o i m p l e m e n t a o n e - s i z e - f i t s - a l l r e p a i r m e t h o d , a n d e n g i n e e r s h a d t o d e v e l o p u n i q u e s o l u t i o n sf o r e a c h d a m a g e d b r i d g e ( C o o p e r 1 9 9 4 ) .C.4.6 Innovations and Lessons LearnedC.4.6.1 General Design FindingsF r o m t h e N o r t h r i d g e E a r t h q u a k e , C a l t r a n s b r i d g e e n g i n e e r s l e a r n e d t h a t a b u t m e n t f i l l f a i l u r e o f t e n l e a d st o a p p r o a c h s l a b f a i l u r e . I n a d e q u a t e l e n g t h s o f a b u t m e n t s e a t s c a u s e d g i r d e r s a n d s l a b s t o f a i l . E x c e s s i v es h e a r o r f l e x u r a l d e m a n d s , o f t e n c a u s e d b y p o o r c o n f i n e m e n t o r d e t a i l i n g , l e a d s t o c o l u m n f a i l u r e .E x c e s s i v e s h e a r o r f l e x u r a l d e m a n d s c a u s e d f o o t i n g f a i l u r e s . G r o u n d f a i l u r e s w e r e d u e t o u n c o n t r o l l a b l el i q u e f a c t i o n ( A l i p o u r 2 0 1 6 ) .C.4.6.2 Emergency ContractsC a l t r a n s h a s e m e r g e n c y c o n t r a c t s a l r e a d y e s t a b l i s h e d , s o w h e n t h e N o r t h r i d g e E a r t h q u a k e h i t , c o n t r a c t o r sc o u l d r e s p o n d i m m e d i a t e l y , a n d w e r e a l r e a d y e q u i p p e d w i t h t h e t o o l s n e c e s s a r y f o r i n s p e c t i o n s a n di d e n t i f i c a t i o n o f r o u t e d e t o u r s . A h e i g h t e n e d l e v e l o f p r e p a r e d n e s s a s d e m o n s t r a t e d b y C a l t r a n s f o l l o w i n gt h e N o r t h r i d g e E a r t h q u a k e h a s e x p r e s s e d b e n e f i t s s u c h a s r e d u c e d c o s t , i n c r e a s e d r o a d u s e r s a t i s f a c t i o n ,a n d m o r e i m m e d i a t e r e s p o n s e t e c h n i q u e s t o b r i d g e a s s e s s m e n t a n d r e s t o r a t i o n .Figure C-17. Severe Concrete Loss of Column and Reinforcement Buckling (Buckle 1994, Photos courtesy of NCREER/MCEER Reports with support from the Federal Government via NSF)

139 C.4.6.3 Base IsolationBase Isolation and energy absorbing technologies may have been a beneficial method of buildingresilience into bridges affected by the Northridge Earthquake. Base isolation and other energy absorbing technologies perform excellently in buildings, but knowledge of their application on bridges is not widespread. Further investigation on the effectiveness of base isolation and energy absorbing technology should be performed as a potentially promising method of preparation for future earthquakes (Cooper 1994). C.4.6.4 Post-Earthquake Inspection Team TrainingOne of the best methods to prepare for a disaster is to train teams of inspectors on how to evaluate bridgesfollowing an earthquake. Caltrans used two-person inspection teams made up of a bridge engineer and maintenance engineer to assess damaged bridges in response to the Northridge Earthquake. The team was responsible for determining if the bridge was safe to open (if closed) and which ones needed additional inspections to further assess the extent of the damage before re-opening (Cooper 1994). Furthermore, municipalities can improve earthquake response efforts by regularly training all emergency responders in the case of earthquake events (Marsh et al. 2013). C.4.6.5 Visual Bridge Catalogs, HAZUS Models, and REDARSFollowing the Northridge Earthquake, government officials, Caltrans, and emergency response planners,developed mitigation response plans by mobilizing inspection teams to assess the damage to bridges. Having a database of bridge conditions and bridge component capacities prior to the earthquake helps streamline earthquake response by mobilizing the PEQIT in order of bridge damage priority. After the Northridge earthquake, Caltrans implemented the Visual Bridge Catalog. The Visual Bridge catalog is used to categorize bridges according to failure mechanism, the shape of the hysteretic backbone (ductile, strength degrading, or brittle), and the damage level. This catalog has over one hundred reinforced concrete bridge references tested in the lab setting. Moreover, the Visual Bridge Catalog can be used to assess the damage to bridges within the epicentral region of an earthquake. The Visual Bridge Catalog contains specifications on over one hundred reinforced concrete columns involved in lab tests. The ability to assess and categorize by level of damage, and identify the failure mechanism, can help streamline the prioritization process post-seismic event (Marsh et al. 2013). Another tool developed out of the Northridge Earthquake is HAZUS. HAZUS is a prediction model which aids in predicting the number of casualties and serious injuries following future earthquakes (Marsh et al. 2013). HAZUS is used in pre-disaster planning as it analyses data related to the physical condition of the bridges and roadways in normal conditions. HAZUS uses Geographic Information Systems (GIS) to geographically locate areas of high-risk which, in the event of a disaster, would have physical, economic, and social impacts on regions affected by the event. Caltrans determined this information would be beneficial to further develop prioritize structures for inspection and focus on retrofit efforts (FEMA 2020). HAZUS models can be used to visualize spatial relationships between the population and geographic assets such as the Santa Monica Freeway, the Gavin Canyon Undercrossing, and the 14/5 interchange, allowing bridge engineers to quickly identify and categorize bridges by damage level and type. With this information, Caltrans emergency response crews can conduct traffic along routes of bridge infrastructure with adequate capacity to handle the flow following an earthquake, while rapidly restoring bridges of the highest priority. Another impactful tool available is REDARS software. REDARS analyzes road user losses relevant to traffic and roadway systems, as can serve as a helpful earthquake hazard mitigation tool. REDARS considers highway redundancies, traffic capacities, and the links between interstates and arterial roads. Caltrans found that software such as REDARS can aid in modeling the extent, type, and location of damage, allowing emergency response teams to determine the traffic volume capability of each bridge throughout

140 the duration of the bridge restoration process. In addition to modeling time-dependent traffic capabilities, REDARS accounts for costs and downtimes needed for bridge repairs, which can help with the bidding process (Marsh et al. 2013). C.4.6.6 Fiber Composite Retrofits as Preventative MeasuresIn preparation of future earthquakes, fiber composite retrofits should be used on bridge columns. TheNorthridge Earthquake was an excellent example of the improved performance of bridge columns which have been retrofitted with fiber composite materials such as CFRP strips and GRFP jackets (Buckle 2006).

1 4 1C.5 Highway 54 over Sanders Creek Bridge 2018 [Flood]Table C-5. Highway 54 over Sanders Creek Bridge FloodCase Study Name/ Date Highway 54 over Sanders Creek Bridge Flood (2018 )L ocation Arkansas, USAEvent Type FloodBridge Name Highway 54 over Sanders Creek BridgeScope/ Costs Replacement of Damaged Bent, cost N/ APlanning Techniques/ Tools N/ AEvent Response Bridge closure Assessment Techniques/ Tools N/ ARapid Restoration Type Replacement of crushed bentInnovations • Purchasing materials from Federal Supply Surplus• Bailey Bridge Jack SystemC.5.1 IntroductionT h i s C a s e S t u d y w a s d e v e l o p e d b a s e d o n t h ei n f o r m a t i o n p r o v i d e d b y A r k a n s a s D e p a r t m e n t o fT r a n s p o r t a t i o n ( A R D O T ) i n t h e Q u e s t i o n n a i r e . T h ei n f o r m a t i o n w a s s u p p l e m e n t e d b y m e d i a s o u r c e d b yR u s l e y 2 0 1 8 .2 0 1 8 F l o o d i n g i n A r k a n s a s l e d t o t h e H i g h w a y 5 4o v e r S a n d e r s C r e e k B r i d g e t o b e i m p a c t e d b y a l a r g ec h u n k o f f l o a t i n g d e b r i s . A c o m b i n a t i o n o f d e b r i si m p a c t a n d p i l e d e t e r i o r a t i o n c r u s h e d t h e w o o d e ni n t e r m e d i a t e b e n t , c a u s i n g t h e b r i d g e t o s i n k ( F i g u r e C -1 8 ) . F o r t u n a t e l y , t h e h i g h w a y t r a v e l v o l u m e s w e r e l o w ,a n d t h e d e t o u r w a s s h o r t . B e c a u s e o f t h i s , A R D O T w a sa b l e t o c u l t i v a t e a n e w e r m e t h o d o f r e p a i r w i t h a B a i l e yB r i d g e s y s t e m t o j a c k u p t h e b r i d g e , a l l o w i n g f o r t h er a p i d r e p l a c e m e n t o f t h e b e n t .C.5.1.1 Event ResponseI m m e d i a t e l y f o l l o w i n g t h e c r u s h i n g o f t h e t i m b e r b e n t s , t h e s t r u c t u r e w a s c l o s e d . I t r e m a i n e d c l o s e d u n t i lt h e r e p a i r s c o u l d b e c o m p l e t e d i n a c o u p l e o f w e e k s .C.5.2 Emergency PlanningN o p l a n n i n g i n f o r m a t i o n w a s a v a i l a b l e .C.5.3 AssessmentN o a s s e s s m e n t i n f o r m a t i o n w a s a v a i l a b l e .Figure C-18. Debris Damaged Columns (Courtesy of Heavy Bridge Maintenance, ARDOT)

1 4 2C.5.4 Rapid RestorationC.5.4.1 Permanent StructureT o r e p a i r t h e b r i d g e , t h e s i n k i n g s u p e r s t r u c t u r e h a d t o b e l i f t e d . T h i s w a s a c c o m p l i s h e d b y c r e a t i n gs a d d l e s t o l i f t t h e b e n t c a p w i t h B a i l e y t r u s s e s e q u i p p e d w i t h j a c k s . F r o m h e r e , t h e c r u s h e d t i m b e r p i l e sw e r e a b l e t o b e r e m o v e d , a n d n e w p i l e s c o u l d b e i n s t a l l e d . T o p l a c e t h e B a i l e y B r i d g e t r u s s , h e a v y - d u t yc a s t e r s w e r e b o u g h t , a n d b r a c k e t s w e r e b u i l t t o c o n n e c t t h e B a i l e y B r i d g e t o t h e c a s t e r s . T h e n t h e c r e wp u s h e d t h e t r u s s e s i n t o p o s i t i o n a n d b o o m t r u c k s o n e a c h s i d e o f t h e b r i d g e a p p r o a c h w e r e u s e d t o l i f t t h eB a i l e y B r i d g e i n t o p l a c e ( F i g u r e C - 1 9 ) .BADCFigure C-19. Permanent Restoration (Courtesy of Heavy Bridge Maintenance, ARDOT) (A) Preparation for Jacking (B) Jacking System in Place (C) Launching of Bailey Bridge (D) Bailey Bridge Installed Across the Structure

1 4 3C.5.5 ChallengesT h e c r u s h e d b e n t p r e v e n t e d a n y h e a v y e q u i p m e n t f r o m b e i n g p l a c e d o n t h e b r i d g e . T h e d e s i g n h a d t oi n c l u d e t h e i n s t a l l a t i o n o f a t e m p o r a r y s p a n t o h e l p l i f t t h e s i n k i n g b r i d g e , w h i c h i n c l u d e d l a u n c h i n g t h es p a n s f r o m t h e r i v e r a p p r o a c h e s .C.5.6 Innovations and Lessons LearnedC.5.6.1 Purchasing of Supplies from Federal SurplusT h e c a s t e r s a n d o t h e r s u p p l i e s u s e d f o r t h i s p r o j e c t w e r e p u r c h a s e d a t t h e F e d e r a l S u r p l u s ( F i g u r e C -2 0 A ) . T h e A r k a n s a s D O T f o u n d t h i s w a s a g r e a t r e s o u r c e t o t a k e a d v a n t a g e o f . T h e D O T h i g h l yr e c o m m e n d s i t t o o t h e r t r a n s p o r t a t i o n a g e n c i e s f o r q u a l i t y m a t e r i a l s a n d e q u i p m e n t f o r a l o w p r i c e .C.5.6.2 Bailey Bridge Jack SystemT y p i c a l l y , B a i l e y B r i d g e s a r e u s e d a s t e m p o r a r y s t r u c t u r e s t o r e o p e n a s t r u c t u r e . H o w e v e r , f o r t h i sp r o j e c t , t h e s y s t e m w a s u s e d t o l i f t t h e c a p a l o n g w i t h t h e s u p e r s t r u c t u r e o f f i t s c r u s h e d p i l e s t o r e p l a c e t h eb e n t ( F i g u r e C - 2 0 B ) . T h i s c r e a t i v e s o l u t i o n s o l v e d t h e p r o b l e m o f l i f t i n g t h e s t r u c t u r e o f f t h e c r u s h e d p i l e sw i t h o u t r e q u i r i n g h e a v y e q u i p m e n t o n t h e s t r u c t u r e . T h e A r k a n s a s D O T h a d p r e v i o u s l y u s e d a B a i l e yB r i d g e t r u s s t o p i c k u p a d a m a g e d s u p e r s t r u c t u r e b e a m , b u t t h i s w a s t h e f i r s t a p p l i c a t i o n o f l i f t i n g a c a pb e a m .BAFigure C-20. Innovations (Courtesy of Heavy Bridge Maintenance, ARDOT) (A) Installation of Casters (B) Replacing the Bent

144 C.6 Michigan 2020 [Flood]Table C-6. Michigan Floods Case Study Name/Date Michigan Floods (2020) Location Michigan, USA Event Type Flood Bridge Name US-10 Bridges over Sanford Lake Scope/Costs Twin bridges with extreme scour damage at abutments due to catastrophic dam failure causes flooding/total cost $1.78 Million Planning Techniques/Tools N/A Event Response Governor ordered Emergency Declaration, establishment of GIS platform for updates on construction and closures Assessment Techniques/Tools Visual assessment, underwater inspection, and drone footage Rapid Restoration Type Riprap, backfilling abutments Innovations • Interactive geographical information system (GIS) map• Governor Declaration of an Emergency Event• Design considerations for bridges located downstream ofmajor damsC.6.1 IntroductionThe 2020 Michigan severe flooding was devastating to the Sanford Lake region. The flooding lead to theEdenville Dam failure on May 19th, 2020, and subsequent overflow of the Sanford Dam, draining their reservoirs and sending millions of gallons of water toward the cities of Midland, Edenville, and Sanford (Schafer 2020). The US Highway 10 Twin Bridges were caught in the wake, and extreme scour washed away part of their abutments. Michigan DOT officials noted they had never seen such extreme scour damage from one event (Heideman 2020). Drone footage and underwater inspections were used to assess the damage, and a combination of backfilling, replacing the bridge approaches, and adding scour countermeasures such as riprap are used to repair the structure and get traffic flowing again. C.6.1.1 Event ResponseMichigan Governor Gretchen Whitmer issued an emergency declaration on May 19th, which was quicklyapproved by President Trump. This permitted Michigan to use an emergency contracting approach to quickly secure a contractor for repairs (Lamb 2020). In response to the floods, the Michigan DOT developed a GIS map to keep motorists updated on closures and construction. The platform also included photos from the different roadways and bridge job sites, including the US-10 bridges. Clear communication between the public and workers helped create a smooth repair process with limited disruptions (Schafer 2020).

1 4 5C.6.2 Emergency PlanningC.6.2.1 Crowdsourcing and Information GatheringH u n d r e d s o f v i d e o s w e r e c o l l e c t e d f r o m e y e w i t n e s s e s o f t h e d a m f a i l u r e , r i s i n g r i v e r w a t e r s , a n d e v e nt h e a f t e r m a t h . P o s t s o n d i f f e r e n t s o c i a l m e d i a p l a t f o r m s w e r e u s e d t o c o l l e c t i n f o r m a t i o n o n t h e i m p a c t a n dd a m a g e a c r o s s t h e c o u n t y ( C h u t e 2 0 2 0 ) .A f t e r t h e D a m f a i l u r e s , i t w a s d i s c o v e r e d t h e E d e n v i l l e D a m h a d a l r e a d y m u l t i p l e v i o l a t i o n s , m o s t o ft h e m s u r r o u n d i n g t h e i n a b i l i t y o f t h e d a m t o h a n d l e e x t r e m e f l o o d w a t e r s .C.6.3 AssessmentA c o m b i n a t i o n o f v i s u a l i n s p e c t i o n s , d r o n e f o o t a g e , a n d u n d e r w a t e r i n s p e c t i o n s w e r e c o n d u c t e d t o a s s e s st h e s i t u a t i o n . T h e u n d e r w a t e r i n s p e c t i o n s ( B r o w n e e t a l . 2 0 1 0 ) w e r e h e a v i l y f o c u s e d o n t h e i n t e r m e d i a t ep i e r s , a s t h e s e d i d n o t h a v e a s m u c h n o t i c e a b l e d a m a g e f r o m t h e s u r f a c e , a n d e n g i n e e r s w a n t e d t o b e s u r et h e r e w a s n o t e x t e n s i v e d a m a g e b e l o w t h e s u r f a c e ( M u r d o c k 2 0 2 0 ) . T h e e x t e n t o f t h e d a m a g e i s s h o w n i nF i g u r e C - 2 1 .C.6.4 Rapid RestorationC.6.4.1 DesignT h e e a s t b o u n d b r i d g e s u f f e r e d l e s s d a m a g e t h a n t h ew e s t b o u n d , s o r e p a i r s w e r e s t a r t e d o n t h i s s t r u c t u r ef i r s t . C o n s t r u c t i o n o n t h e e a s t b o u n d b r i d g e w a sc o m p l e t e d b y J u n e 4 t h , w h i c h o p e n e d t h e b r i d g e t o o n el a n e o f t r a f f i c i n e a c h d i r e c t i o n ( L a m b 2 0 2 0 ) . T o m a k et h i s p o s s i b l e , a c r o s s o v e r s y s t e m w a s f i r s t c o n s t r u c t e dt o p r o v i d e w e s t b o u n d t r a f f i c a c c e s s t o t h e e a s t b o u n db r i d g e ( H e i d e m a n 2 0 2 0 ) . O n J u n e 1 4 t h , t h e w e s t b o u n db r i d g e o p e n e d , r e s t o r i n g n o r m a l t r a f f i c p a t t e r n s ( L a m b2 0 2 0 ) . T h e t o t a l c o s t o f r e p a i r s t o t a l e d $ 1 . 7 8 m i l l i o n( H e i d e m a n 2 0 2 0 ) .C.6.4.2 Permanent StructureT o r e p a i r t h e r e g i o n b e h i n d t h e a b u t m e n t t h a t w a s h e d a w a y , t h e d a m a g e d b r i d g e a p p r o a c h e s w e r er e m o v e d , a n d t r e e s a n d o t h e r d e b r i s w e r e c a r r i e d o f f t h e b r i d g e . T h e n , s m a l l r o c k s a n d s a n d w e r e b a c k f i l l e db e h i n d t h e a b u t m e n t ( F i g u r e C - 2 1 ) . N e w a p p r o a c h e s w e r e p o u r e d , a n d s c o u r c o u n t e r m e a s u r e s s u c h a sr i p r a p w a s a d d e d . T h e r i p r a p w a s m a d e u p o f l a r g e r o c k s c o v e r i n g t h e a b u t m e n t s . T h e g a p b e t w e e n t h eb a c k f i l l a n d r i p r a p w a s p r e s s u r e g r o u t e d t o s e c u r e t h e a b u t m e n t s ( M u r d o c k 2 0 2 0 ) .C.6.5 ChallengesT h e b i g g e s t c h a l l e n g e w i t h t h e r e p a i r s w a s t h e C O V I D - 1 9 p a n d e m i c . C o o r d i n a t i o n o f r e c o v e r y e f f o r t sa n d r e p a i r p l a n s n e e d e d t o b e d e v e l o p e d w i t h C O V I D r e s t r i c t i o n s i n m i n d . H o w e v e r , s o m e w o r k e r s c l a i mt h e y w e r e n o t p r o v i d e d w i t h t h e e s s e n t i a l p e r s o n a l p r o t e c t i v e e q u i p m e n t s u c h a s m a s k s , w e r e n o t r e q u i r e dt o w e a r m a s k s o n s i t e , a n d w e r e d i r e c t e d t o p e r f o r m t a s k s w i t h o u t r e g a r d f o r p r o p e r s o c i a l d i s t a n c i n g( W a r i k o o 2 0 2 0 ) .Figure C-21. Repairs to US-10 Bridge Approaches (Michigan Department of Transportation 2020)

146 C.6.6 InnovationsC.6.6.1 Geographic Information System (GIS)During the major floods, MDOT developed an interactive GIS map for the public to use, informing themof closures and detours caused by the flood-damaged roads and bridge. Real-time updates and project photos were included on the map, establishing transparency with the public. C.6.6.2 Declaration of an Emergency EventGovernor Gretchen Whitmer’s declaration of an Emergency Event permitted the use of emergencycontracts, which expedited the repair process. The ability to enact emergency protocols acknowledges the sense of urgency with the project and reduces the economic loss from the closures and detours, ultimately helping the community recover quicker. C.6.6.3 Special Considerations for Bridges Downstream from DamsBridges located downstream of major dams should consider partial or full dam failure as part of theirinitial design or later retrofit. Examples of these precautions include extra protection for scour and severe flooding to reduce the likelihood of catastrophic failure.

1 4 7C.7 I-69 Southbound Bridge 2017 [Hurricane]Table C-7. I-69 Southbound Bridge Hurricane HarveyCase Study Name/ Date I-69 Southbound Bridge Hurricane Harvey (2017 )L ocation Texas, USAEvent Type HurricaneBridge Name I-69 Southbound BridgeScope/ Costs 3 Bents repaired and 4 Spans replaced, estimated total cost $ 7 .5 millionPlanning Techniques/ Tools N/ AEvent Response Traffic rerouted to Northbound Bridge during constructionAssessment Techniques/ Tools • Fish Finder-like device• V isual Inspection• Acoustic ImagingRapid Restoration Type Precast beams and panelsInnovations • Incentives/ disincentives for early completion or late finishC.7.1 IntroductionH u r r i c a n e H a r v e y d u m p e d o v e r 1 9 t r i l l i o n g a l l o n s o fw a t e r o v e r T e x a s i n 2 0 1 7 . T h i s m a s s i v e q u a n t i t y o fw a t e r f l o o d e d c i t i e s a n d e v e n c h a n g e d t h e c o u r s e o fs o m e r i v e r s , l i k e i n t h e c a s e o f t h e S a n J a c i n t o R i v e rn e a r H u m b l e , T X . T h e S a n J a c i n t o R i v e r d e e p e n e d ,l e a d i n g t o e x t r e m e s c o u r o f t h e I - 6 9 S o u t h b o u n dB r i d g e , a s s h o w n i n F i g u r e C - 2 2 . T h e s t r u c t u r e w a su n a b l e t o c a r r y t y p i c a l f r e e w a y l o a d s d u e t o t h eu n s t a b l e s u b s t r u c t u r e , s o i t w a s c l o s e d a f t e r H u r r i c a n eH a r v e y f o r c r e w s t o r e m o v e a n d r e b u i l d t h e s c o u rd a m a g e d b e n t s a n d t h e i r c o r r e s p o n d i n g s p a n s ( F i g u r eC - 2 3 ) . T h e $ 7 . 5 m i l l i o n p r o j e c t u s e d p r e c a s t c o n c r e t eb e a m s a n d p a n e l s , w i t h e q u i p m e n t b r o u g h t t o t h e s i t ev i a b a r g e . T h e p r o j e c t w a s c o m p l e t e d i n 1 8 2 d a y s ,w h i c h w a s a h e a d o f s c h e d u l e ( T o b i a 2 0 1 8 ) . O v e r a l l ,t h e r e p a i r w a s t h e l a r g e s t b r i d g e c o n s t r u c t i o n p r o j e c tf o l l o w i n g H u r r i c a n e H a r v e y ( P o i r i e r 2 0 1 8 ) .C.7.1.1 Event ResponseW h i l e t h e S o u t h b o u n d B r i d g e w a s c l o s e d f o rc o n s t r u c t i o n , t r a f f i c w a s r e r o u t e d t o t h e N o r t h b o u n dB r i d g e , w h i c h w a s r e c o n f i g u r e d t o a c c o m m o d a t et r a f f i c i n b o t h d i r e c t i o n s . T h i s k e p t t r a f f i c f l o w i n gd u r i n g r e p a i r a n d l i m i t e d t h e d i s r u p t i o n t o c o m m e r c e( D e l a u g h t e r 2 0 1 8 ) .Figure C-23. Scour Damage at Bent (Images courtesy of Padgett et al. 2018)Figure C-22. San Jacinto River Flooding Over I-69 (Kirk 2018)

148 C.7.2 Emergency PlanningNo emergency planning information was available.C.7.3 AssessmentThe original I-69 Southbound Bridge was built in 1961. It was widened twice, once in 1982 and again in1994. Eyewitnesses caught images of the bridge submerged under the San Jacinto River during Hurricane Harvey. A few days after Hurricane Harvey, a reconnaissance team visited the I-69 Southbound Bridge and adjacent Northbound and Frontage Road structures. The team completed a visual inspection of the bridges, and found there was no visible pavement damage, however there were debris found pushed up against the structure and stuck on the adjacent Frontage Road Bridges. Moreover, scour holes were noted near the bents (Padgett et al. (2018)), as shown in Figure C-24. The research team recommended that all the structures needed additional inspections and repairs to restore the structural capacity and prevent future damage in future flooding or hurricane events (Padgett et al. 2018). The Texas DOT used a SHIFLO, which is a fish finder device mounted on a ski. This device was used to measure the channel depth to determine the extent of the scour. Additionally, acoustic imaging was used to confirm the scour damage observed with visual assessments and the fish finder (Questionnaire). It was later determined the southbound bridge would not collapse, but had a substantially reduced load capacity, which led to the bridge remaining open with a new load posting. After plans for repair were developed, the bridge was closed, and construction began (Tobia 2018). C.7.4 Rapid RestorationC.7.4.1 ContractingThe estimated overall total cost for the project was $7.5 million. To incentivize early completion, crewsworked 24/7 with early incentive and late disincentives. Two major project milestone were used to track progress (Poirier 2018). The incentive bonus was $500,000 for early completion (Begley 2018). C.7.4.2 DesignTo reduce the likelihood of damage from future flooding and hurricane events, the bridge’s foundationalfootprint was reduced to match that of the adjacent structures. This was accomplished by installing a new foundation. Drilled shafts were used as part of the new foundation (Poirier 2018). To expedite the repair process, the design also included the replacement of the spans above the new foundation repairs (Questionnaire). C.7.4.3 Permanent StructureTo start repairs, the southbound bridge was closed, and traffic was rerouted to the northbound side. Afterdemolition, the new foundation was built with drilled shafts, which were designed to withstand scour. In total, 3 bents were removed and 4 spans (Poirier 2018). All construction was completed by equipment placed on barges, as shown in Figure C-25 and Figure C-26. Precast deck panels and beams were used,

1 4 9s p e e d i n g u p t h e a c t u a l c o n s t r u c t i o n p r o c e s s . T r a d i t i o a n l c o n s t r u c t i o n m e t h o d s w e r e u s e d i n t a n d e m w i t ht h e p r e c a s t e l e m e n t s f o r a f a s t e r r e p a i r ( q u e s t i o n n a i r e ) .ADCBFigure C-24. Damage Observed (Images courtesy of Padgett et al. (2018)) (A) Scour Along Column Bents (B) Debris Build-Up (C) Debris Trapped at Deck Level (D) Erosion Along Bank

1 5 0C.7.5 ChallengesT h e d a m a g e t o t h e s o u t h b o u n d b r i d g e i m p a c t e dt r a f f i c , e s p e c i a l l y o v e r s i z e d v e h i c l e s . D u e t o t h e s c o u rd a m a g e , t h e s t r u c t u r e w a s u n a b l e t o c a r r y h e a v i l yl o a d e d v e h i c l e s . H o w e v e r , t h i s r o u t i n e h e a v y - h a u l t r u c kt r a f f i c w a s a b l e t o b e r e r o u t e d t o t h e a d j a c e n t f r o n t a g er o a d s , a s t h i s c r o s s i n g o f t h e S a n J a c i n t o R i v e r h a sm u l t i p l e b r i d g e s i n a s h o r t a r e a ( F i g u r e C - 2 7 ) . D u r i n gt h e r e p a i r s , t h e d i s r u p t i o n t o t r a f f i c w a s a l s o l i m i t e d d u et o t h e s e a d j a c e n t s t r u c t u r e s , a s t r a f f i c c o u l d e a s i l y b ed i r e c t e d t o t h e n o r t h b o u n d b r i d g e o r t h e f r o n t a g e r o a d s .C.7.6 Innovations and Lessons LearnedC.7.6.1 Span Replacement & Foundation RepairT h e d e c i s i o n t o r e p l a c e t h e s p a n d i r e c t l y a b o v e t h ef o u n d a t i o n r e p a i r h e l p e d s p e e d u p t h e r e p a i r p r o c e s s .W i t h o u t t h e r e p l a c e m e n t , i t w o u l d h a v e b e e n e x t r e m e l yd i f f i c u l t t o p r e s e r v e t h e s p a n s w h i l e i n s t a l l i n g t h e n e wd r i l l e d s h a f t s . E v e n t h o u g h i t s o u n d e d l i k e m o r e w o r k ,r e m o v i n g t h e o l d s p a n a n d h a v i n g t h e o p e n r e g i o n f o rt h e c o n s t r u c t i o n h e l p e d e x p e d i t e t h e e n t i r e p r o c e s s( q u e s t i o n n a i r e ) .Figure C-26. Construction of New Spans (Tobia 2018)Figure C-25. Crane Working from Barge (Google Maps 2018)Figure C-27. Adjacent Structures (Texas Department of Transportation 2018)

1 5 1C.8 Katrina 2005 [Hurricane]Table C-8. Hurricane KatrinaCase Study Name/ Date Hurricane Katrina (2005)L ocation L ouisiana, USAEvent Type Hurricane Bridge Name I-10 Twin BridgesScope/ Costs 54 Spans Collapsed into the water and 47 3 spans had shifted alignments, total repair cost $ 30 million, replacement $ 7 53 millionPlanning Techniques/ Tools Seeking advice from other DOTs who experienced similar damaged bridges; group proposal development with bridge engineers, maintenance crews, and inspectors.Event Response Preliminary inspection completed 1 day afterAssessment Techniques/ Tools Comparisons to similar structures; lab testsRapid Restoration Type Temporary repairs, later replacementInnovations • Repairing damaged spans to use with adjacent bridge toreopen bridge to traffic sooner• Considerations of buoyant forces with designsC.8.1 IntroductionO n A u g u s t 2 9 t h , 2 0 0 5 , t h e C a t e g o r y - 5 H u r r i c a n e K a t r i n a h i tm u c h o f t h e G u l f r e g i o n o f t h e U n i t e d S t a t e s . H u n d r e d s o f b r i d g e ss u f f e r e d d a m a g e , i n c l u d i n g t h e L a k e P o n t c h a r t r a i n I - 1 0 T w i nB r i d g e s . T h e t w i n b r i d g e s h a d 5 4 c o l l a p s e d s p a n s a n d 4 7 3m i s a l i g n e d s p a n s c a u s e d b y d e c k m o v e m e n t d u e t o u p w a r db u o y a n t f o r c e s a s s h o w n i n F i g u r e C - 2 8 . A t o t a l c o s t o f $ 3 0m i l l i o n w a s e s t i m a t e d f o r t h e t e m p o r a r y s t r u c t u r e s a n d r e p l a c e m e n t . S i n c e I n t e r s t a t e 1 0 i s p a r t o f t h e N a t i o n a l D e f e n s eN e t w o r k , i t w a s k e y t o g e t t h e f r e e w a y u p a n d r u n n i n g a s s o o n a sp o s s i b l e . T e m p o r a r y r e p a i r s o f b o t h b r i d g e s w e r e t h e f o c u s , t h e no n c e t r a f f i c w a s r e o p e n e d , p l a n s f o r t w i n r e p l a c e m e n t b r i d g e sw e r e d e v e l o p e d ( P a d g e t t e t a l . 2 0 0 8 ) .C.8.1.1 Event ResponseA d a y a f t e r H u r r i c a n e K a t r i n a h i t , a t e a m o f L A D O T Di n s p e c t o r s m a d e a p r e l i m i n a r y i n s p e c t i o n o f t h e t w i n b r i d g e s .A d d i t i o n a l i n s p e c t i o n s w e r e c o n d u c t e d i n t h e d a y s a n d w e e k s t h a tf o l l o w e d ( A l i p o u r 2 0 1 6 ) . F i g u r e C - 2 9 s h o w s t h e s u r r o u n d i n g a r e ao f t h e I - 1 0 T w i n B r i d g e s .Figure C-28. Aerial View of Damaged and Missing Spans (Alipour 2016)Figure C-29. Map of Twin I-10 Bridges Region (Chen et al. 2007 with funding from USGS)

1 5 2C.8.2 Emergency PlanningC.8.2.2 Crowdsourcing and Information GatheringT h e s t a t e o f F l o r i d a s u f f e r e d s i m i l a r d a m a g e f r o m w i t h t h e I - 1 0 E s c a m b i a B r i d g e f r o m a p r e v i o u sh u r r i c a n e . L A D O T D m e t w i t h t h e F l o r i d a D O T t o d i s c u s s k e y t a k e a w a y s F l o r i d a h a d w i t h t h e i r t w i n b r i d g er e p a i r , a n d w h a t t o o l s a n d e q u i p m e n t w e r e n e e d e d ( A l i p o u r 2 0 1 6 ) .C.8.3 AssessmentT h e I - 1 0 B r i d g e s w e r e g i v e n t h e H A Z U S d a m a g e c a t e g o r y o f“ c o m p l e t e ” , i n d i c a t i n g c o l l a p s e o r c o n n e c t i o n l o s s a t b e a r i n g sc a u s i n g d e c k c o l l a p s e o r s u b s t r u c t u r e t i l t i n g . D e s p i t e a r e l a t i v e l yl o w t o r m s u r g e o f 4 . 0 2 m , t h e d a m a g e w a s s i g n i f i c a n tc o m p a r e d t o o t h e r d a m a g e d b r i d g e s s u b j e c t t o s i m i l a r s u r g eh e i g h t s ( P a d g e t t e t a l . 2 0 0 8 ) .I t w a s n o t e d t h a t t h e h i g h e r s p a n s t o w a r d t h e c e n t e r o f t h el a k e ’ s n a v i g a t i o n c h a n n e l d i d n o t s u f f e r t h e s a m e l e v e l s o fd a m a g e a s t h e l o w e r a p p r o a c h s p a n s . T h i s f i n d i n g s u g g e s t s t h a tt h e c a u s e f o r t h e b r i d g e c o l l a p s e w a s b u i l t - u p h y d r o s t a t i cp r e s s u r e , w h i c h m a d e i t e a s i e r f o r t h e s p a n s t o f l o a t a w a y . L a bt e s t s w e r e c o n d u c t e d w i t h r e p l i c a g i r d e r s a n d f o u n d t h a t i f o n l y5 5 % o f t h e v o l u m e w a s f i l l e d w i t h t r a p p e d a i r , t h e s p a n s w e r ea b l e t o f l o a t a w a y . U s i n g s u r g e d a t a , i t i s e s t i m a t e d t h e b r i d g e se x p e r i e n c e d u p t o 7 0 % o f f i l l e d v o i d s , s i g n i f i c a n t l y h i g h e r t h a nt h e 5 5 % t h r e s h o l d t h a t w o u l d i n i t i a t e f l o a t i n g s p a n s . W i t h t h i sb u o y a n c y , i t w o u l d o n l y t a k e t h e s l i g h t e s t h o r i z o n t a l d i s t u r b a n c et o s h i f t t h e s p a n s o f f t h e b e n t s a n d c a u s e t h e 5 0 + m i s s i n g s p a n sa n d h u n d r e d s o f s h i f t e d s p a n s . F u r t h e r m o r e , t h e a d j a c e n tH i g h w a y 1 1 b r i d g e s p a n d i d n o t e x p e r i e n c e t h e s a m e d a m a g e a st h e I - 1 0 B r i d g e s . T h e d e s i g n o f t h e g i r d e r s i n t h e I - 1 0 B r i d g e si n c l u d e d h o l e s t h r o u g h t h e m t o r e l i e v e t h e h y d r o s t a t i c p r e s s u r eb u i l d - u p , a s s h o w n i n F i g u r e C - 3 0 . F u r t h e r i n l a n d o n t h e l a k e , a r a i l r o a d b r i d g e a l s o d i d n o t e x p e r i e n c e t h es a m e d a m a g e , a n d t h a t b r i d g e ’ s d e s i g n i n c l u d e d s o l i d d e c k s l a b s , w h i c h d i d n o t a l l o w f o r a n y b u i l t - u ph y d r o s t a t i c p r e s s u r e . T h e s e e m p r i c a l f i n d i n g s i m p l y t h a t a p p r o r i a t e s u r g e - r e s i s e n t b r i d g e - s p a n d e s i g n i se s s e n t i a l t o w a t e r - c r o s s i n g b r i d g e s i n h u r r i c a n e p r o n e c o a s t a l r e g i o n s .C.8.4 Rapid RestorationC.8.4.1 ContractingF u n d i n g f o r t h e r e p a i r s , l i k e m o s t o f t h e b r i d g e s d a m a g e d b y H u r r i c a n e K a t r i n a , w e r e f r o m F E M A o rE m e r g e n c y R e s p o n s e ( E R ) f u n d s . A f t e r a p l a n w a s d e v e l o p e d t o r e p a i r t h e t w i n b r i d g e s , a p r e - b i d m e e t i n gw a s h e l d w i t h v a r i o u s c o n t r a c t o r s , b r i d g e d e s i g n e r s , a n d m a i n t e n a n c e c r e w s t o d e v e l o p a p r o p o s a l f o r t h ep r o j e c t . A l t o g e t h e r , t h e t e a m d e v e l o p e d f o u r p h a s e s f o r t h e p r o j e c t ( A l i p o u r 2 0 1 6 ) .Figure C-30. Highway 11 Bridge Girder Opening (Chen et al. 2007 with funding from USGS)

1 5 3C.8.4.2 Temporary StructureI n P h a s e 1 , s p a n s f r o m t h e w e s t b o u n d l a n e s w e r em o v e d t o f i l l i n m i s s i n g s p a n s i n t h e e a s t b o u n d l a n e su s i n g S e l f P r o p e l l e d M o d u l a r T r a n s p o r t e r s ( S P M T ) o nb a r g e s . R e p a i r s w e r e m a d e t o a l i g n t h e s h i f t e d s p a n s ,a s s h o w n i n F i g u r e C - 3 1 . T h i s p r o c e s s t o o k a ne s t i m a t e d 4 5 d a y s t o c o m p l e t e , a n d t h e c o n t r a c t o r w a so f f e r e d i n c e n t i v e s / d i s i n c e n t i v e s f o r e a r l y o r d e l a y e dc o m p l e t i o n . W i t h t h e e a s t b o u n d l a n e s ’ t e m p o r a r yr e p a i r s , t r a f f i c w a s a b l e t o r e s u m e a c r o s s t h e l a k e o n l y4 2 d a y s a f t e r t h e H u r r i c a n e ( A l i p o u r 2 0 1 6 ) .F o r P h a s e 2 , t h e s c a v e n g e d w e s t b o u n d b r i d g e w a sr e p l a c e d w i t h p r e f a b b r i d g e s ( p r o v i d e d b y t h e A c r o wB r i d g e s ) , w h i c h a r e a t y p e o f s t e e l m o d u l a r s t r u c t u r e .W i t h t h e s e t e m p o r a r y b r i d g e s i n s t a l l e d , t h e w e s t b o u n db r i d g e w a s t h e n r e o p e n e d t o t r a f f i c A l i p o u r 2 0 1 6 ) .P h a s e 3 i n c l u d e d m a i n t a i n i n g t h e r e p a i r e d e a s t b o u n d b r i d g e a n d t h e A c r o w w e s t b o u n d b r i d g e u n t i l a t o t a lr e p l a c e m e n t ( A l i p o u r 2 0 1 6 ) .C.8.4.3 Permanent StructureI n P h a s e 4 , p l a n s f o r t h e r e p l a c e m e n t b r i d g e w e r e d e v e l o p e d a n d t h e n e w b r i d g e s w e r e b u i l t ( A l i p o u r2 0 1 6 ) . T h e n e w t w i n b r i d g e s u s e 3 6 - i n c h p r e c a s t p i l e s f o r t h e s u b s t r u c t u r e . T h e t w o b r i d g e s c a r r y 3 l a n e si n t o t a l w i t h 1 2 - f o o t - w i d e s h o u l d e r s . A t m i d s p a n o f t h e b r i d g e s , t h e s t r u c t u r e r i s e s t o a c c o m m o d a t e t h ep a s s i n g s h i p t r a f f i c . T o r e d u c e t h e t h r e a t o f s h i p i m p a c t , p i l e s u p p o r t e d w a t e r l i n e f o o t i n g s w e r e i n s t a l l e dn e a r t h e s h i p n a v i g a t i o n c h a n n e l ( M a s s m a n C o n s t r u c t i o n C o m p a n y 2 0 2 0 ) . T h e r e p l a c e m e n t c o s t o f $ 7 5 3m i l l i o n , a n d w a s f u l l y f u n d e d b y t h e F H W A , a n d i n c l u d e d s p e c i f i c a t i o n s o n t r a f f i c m a i n t e n a n c e , r i g h t - o f -w a y , a n d t h e e n v i r o n m e n t w i t h t h e d e s i g n . C o n s t r u c t i o n i n c l u d e d t h r e e p h a s e s , w i t h p h a s e 1 i n c l u d i n g t h es u b s t r u c t i o n e r e c t i o n , p h a s e 2 i n c l u d e d t h e c o n c r e t e s p a n s , a n d p h a s e 3 t h e n a v i g a t i o n c h a n n e l . T w o d e s i g n -b i d - b u i l d c o n t r a c t s w e r e u s e d , o n e f o r p h a s e s 1 a n d 2 , a n d t h e o t h e r f o r p h a s e 3 . O t h e r c o n s i d e r a t i o n si n c l u d e d a 1 0 0 - y e a r s e r v i c e l i f e , s t o r m a n d c o l l i s i o n i m p a c t r e s i s t a n c e , a n d a r a p i d c o m p l e t i o n . T h e b e n tp l a c e m e n t w a s d e s i g n e d t o m a x i m i z e t h e s p a n l e n g t h s t o r e d u c e t h e n u m b e r o f r e q u i r e d i n t e r m e d i a t es u p p o r t s . T h e t w i n b r i d g e s u s e d p r e f a b r i c a t e d c o n c r e t e p i l e s , b e n t c a p s , g i r d e r s , a n d s t a y - i n - p l a c e f o r m s f o rt h e p i l e f o o t i n g s ( D ' A n d r e a 2 0 1 1 ) .T h e p i l e d e s i g n t o o k l a r g e m o m e n t c a p a c i t i e s i n t o c o n s i d e r a t i o n f o r s t o r m a n d i m p a c t r e s i s t a n c e . T oc o n n e c t t o t h e p r e c a s t b e n t , a c o n c r e t e m o m e n t p l u g w a s u s e d , a n d d e p e n d i n g o n t h e l o c a t i o n o f t h e b e n t ,e x t e n d e d 3 0 f e e t . S o m e a r e e v e n d e s i g n e d t o r e s i s t u p l i f t c a u s e d b y b u o y a n t f o r c e s . F o r t h e f o o t i n g s ,c o n s t r u c t i o n w a s m a d e e a s i e r b y s e t t i n g t h e i r e l e v a t i o n a b o v e t h e h i g h - w a t e r l e v e l . T h e g i r d e r s w e r ed e s i g n e d f o r m a x i m u m l e n g t h a n d s p a c i n g , p e r m i t t i n g t h e u s e o f l a r g e r p r e s t r e s s i n g f o r c e s . B y u s i n g b a r g e st o t r a n s p o r t m a t e r i a l s t o t h e s i t e , t h e c o n t r a c t o r d i d n o t h a v e t o w o r r y a b o u t t h e s h i p m e n t o f t h e l a r g e g i r d e r s .A c o n t i n u o u s c a s t - i n - p l a c e d e c k w a s p o u r e d o n t o p , r e d u c i n g t h e n u m b e r o f j o i n t s . O n c e t h e n e w s t r u c t u r e sw e r e b u i l t , t h e e x i s t i n g b r i d g e s w e r e t o r n d o w n , a n d t h e m a t e r i a l s s a l v a g e w e r e u s e d t o l i n e t h e s h o r e l i n e ,c r e a t i n g r e e f s f o r n a t i v e f i s h ( D ' A n d r e a 2 0 1 1 ) .C.8.5 ChallengesT h e b i g g e s t d r i v i n g f a c t o r f o r t h i s p r o j e c t w a s t i m e . I t w a s d e t e r m i n e d t h e b e s t c o u r s e o f a c t i o n w a s t os t a r t w i t h t h e t e m p o r a r y r e p a i r o f o p e n i n g o n b r i d g e t o t r a f f i c , t h e n f o c u s o n t h e p e r m a n e n t r e p l a c e m e n tFigure C-31. Girders Fallen off Bent (Alipour 2016)

1 5 4s t r u c t u r e s i n t h e f u t u r e . T h i s d e c i s i o n a l l o w e d f o r m o r e t i m e w i t h t h e p e r m a n e n t s t r u c t u r e d e s i g n a n d g a v et h e o p p o r t u n i t y f o r t h e s t a t e t o i n v e s t i g a t e d i f f e r e n t f u n d i n g s o u r c e s .C.8.6 Innovations and Lessons LearnedC.8.6.1 Use of GIS Database for Prediction ModelsT o b e t t e r p r e p a r e f o r t h e n e x t H u r r i c a n e , t h e L A D O T D d e v e l o p e d a w a v e / s u r g e a t l a s . U s i n g 1 0 0 - y e a rd e s i g n s t o r m d a t a , a G I S d a t a b a s e w a s e s t a b l i s h e d t o i d e n t i f y t h e b r i d e s a t r i s k a n d u s e d b r i d g ec h a r a c t e r i s t i c s s u c h a s w e i g h t t o l o c a t e t h e m o s t v u l n e r a b l e s p a n ( s ) o n t h e e n t i r e b r i d g e . W i t h f u n d i n g , t h e s eb r i d g e s c o u l d t h e n b e r e t r o f i t t e d t o b e t t e r p r e p a r e f o r a m a j o r d i s a s t e r o r i n d i c a t e w h e r e i n s p e c t i o n s s h o u l ds t a r t a f t e r a s t o r m s u r g e o r h u r r i c a n e ( A l i p o u r 2 0 1 6 ) .C.8.6.2 Considering Buoyant Forces in Hurricane Bridge DesignD u r i n g a h u r r i c a n e o r m a j o r f l o o d i n g e v e n t , d a m a g em i g h t n o t b e f r o m t h e c o m m o n c a u s e s s u c h a s d e b r i si m p a c t o r s c o u r , b u t f r o m t h e b u o y a n t f o r c e s o n t h eb r i d g e s . B r i d g e s a r e n o t a l w a y s d e s i g n e d f o r u p l i f t , a n dt h e y s h o u l d b e d e s i g n e d t o n o t t r a p a i r u n d e r t h e d e c ko r i n t h e s u p e r s t r u c t u r e t o p r o v i d e s o m e r e l i e f t o t h e s ef o r c e s . F i g u r e C - 3 2 h i g h l i g h t s t h i s f l a w e d d e s i g n .A d d i t i o n a l l y , b r i d g e s s e i s m i c i t y - i n a c t i v e r e g i o n s a r en o t a l w a y s d e s i g n e d t o d y n a m i c f o r c e s i n m i n d , a n d t h i sc a n c a u s e i s s u e s d u r i n g d y n a m i c m o v i n g o f w a t e r .S t a t i c d e s i g n s s h o u l d s t i l l b e u s e d , b u t d y n a m i c f o r c e ss h o u l d a l s o b e c o n s i d e r e d f o r w a t e r - c r o s s i n g b r i d g e ss u b j e c t t o e x t r e m e f l o o d o r s u r g e e v e n t s . T o c o n s i d e rd y n a m i c l a t e r a l l o a d i n g s f r o m w a t e r , t h e s h e a r k e y s s h o u l d b e i n s t a l l e d t o h o l d g i r d e r s i n p l a c e ( R o b e r t s o ne t a l . 2 0 0 7 ) .Figure C-32. Girder Design Creating Trapped Air (Chen et al. 2007 with funding from USGS)

1 5 5C.9 I-95 Chester Creek Bridge 1998 [Fire]Table C-9. I-95 Chester Creek Bridge Case Study Name/ Date I-95 Chester Creek Bridge (1998 )L ocation Pennsylvania, USAEvent Type FireBridge Name I-95 Chester Creek BridgeScope/ Costs All three southbound lanes for a total cost of $ 4 millionPlanning Techniques/ Tools Expedited emergency contracting proceduresEvent Response Modification of traffic flow on the northbound lanes to accommodate southbound traffic as well.Assessment Techniques/ Tools V isual InspectionRapid Restoration Type Temporary lane additions; replacement of nine girders, deck section repairs, and bent repairs.Innovations • Active involvement of state leadership (i.e., Governor,PennDOT Chief Construction Engineer) streamlined theapproval process and expedited the response and repair• Easily accessible existing design plans, design calculations,and shop drawingsC.9.1 IntroductionT h e C h e s t e r C r e e k B r i d g e w a s b u i l t i n 1 9 6 5 , w i t h at h r e e - s p a n c o n t i n u o u s s t e e l g i r d e r d e s i g n a n d ac o n c r e t e d e c k . T h e s u b s t r u c t u r e w a s c o m p o s e d o fc o n c r e t e b e n t s . O n M a y 2 3 r d , 1 9 9 8 , a g a s o l i n e t a n k e rt r u c k c o l l i d e d w i t h t h e I - 9 5 C h e s t e r C r e e k B r i d g ec e n t e r m e d i a n , f l i p p i n g o v e r t h e b a r r i e r , a n d c r o s s i n gt r a f f i c o n t h e s o u t h b o u n d l a n e s . T h e t r u c k i m p a c t e da n o t h e r v e h i c l e a n d s p i l l e d 8 7 0 0 g a l l o n s o f f u e l , w h i c hb u r s t i n t o f l a m e s . T h e s o u t h b o u n d l a n e s o f t h e b r i d g ee x p e r i e n c e d s e v e r e d a m a g e f r o m t h e f i r e ( T h eW a s h i n g t o n P o s t 1 9 9 8 ) . E n g i n e e r s d e c i d e d t o r e p l a c et h e d a m a g e d p o r t i o n s w i t h a n i d e n t i c a l s t r u c t u r e , f o r at o t a l c o s t o f $ 4 m i l l i o n , a s s h o w n i n F i g u r e C - 3 3 ( B a ia n d B u r k e t t 2 0 0 6 ) .C.9.1.1 Event ResponseI m m e d i a t e l y f o l l o w i n g t h e c r a s h , t h e P e n n s y l v a n i a D e p a r t m e n t o f T r a n s p o r t a t i o n ( P e n n D O T ) c l o s e db o t h d i r e c t i o n s o f t r a f f i c t o m a i n t a i n t h e p u b l i c ’ s s a f e t y u n t i l t h e s t r u c t u r e c o u l d b e a s s e s s e d b y b r i d g ee n g i n e e r s ( B a i , B u r k e t t , a n d N a s h 2 0 0 6 ) . A f t e r a s s e s s i n g t h e b r i d g e , e n g i n e e r s d e t e r m i n e d t h e s o u t h b o u n dl a n e s w e r e u n a b l e t o c a r r y a n y t r a f f i c l o a d s d u e t o t h e f i r e d a m a g e . I n s t e a d o f u s i n g a l o n g - t e r m l e n g t h yd e t o u r r o u t e , t h e y d e c i d e d t o m o d i f y t h e t r a f f i c f l o w o f t h e u n a f f e c t e d n o r t h b o u n d l a n e s t o c a r r y t r a f f i c f r o mb o t h n o r t h a n d s o u t h d i r e c t i o n s ( B a i , B u r k e t t , a n d N a s h 2 0 0 6 ) .Figure C-33. Placement of New Girders (Bai and Kim 2007)

156 The temporary lane construction started the same day as the event. Over 200 laborers worked through the night and removed over 140 feet of concrete median barriers to build the crossovers (Bai, Burkett, and Nash 2006). The three northbound lanes were narrowed to eleven feet, and an additional lane was added. Two lanes were used for northbound and two for southbound traffic. A 40mph speed limit was also imposed during construction, and this was patrolled by State Police for worker and driver safety (Bai and Kim 2007). C.9.2 Emergency PlanningNo information was available for emergency planning information after the event.C.9.3 AssessmentBridge engineers from PennDOT arrived on scene as soon as was possible to complete visual assessmentsof the bridge. They found nine girders were damaged on the southbound lanes, and portions of the concrete deck and a segment of one of the concrete bents needed to be repaired. In total, 2/3 of the southbound superstructure was deemed unsafe and required replacement (Bai, Burkett, and Nash 2006). C.9.4 Rapid RestorationC.9.4.1 ContractingTo avoid a lengthy bidding process, the Governor of Pennsylvania declared the fire a state emergency.This permitted PennDOT to expedite the entire repair process, as it allowed them to forgo typical procedures and regulations. PennDOT was able to hire, purchase, and contract with the firm of their choosing. The secretary of PennDOT selected the same contractor who built the original structure. The firm was paid on a time and materials basis. Mark-ups for prices corresponding to previous PennDOT standards were also used, along with incentives/disincentives for project milestones. All contracting and general procedures followed PennDOT’s previously established PUB 408 document, which helped expedite the processes even further. PUB 408 is PennDOT’s specifications manual which contains requires for construction and contracting procedures (Bai and Burkett 2006). The contractor was responsible for building the crossovers needed to create temporary lanes on the northbound side. Once this was completed, they repaired the damaged girders and deck (Bai, Burkett, and Nash 2006). The demolition of the damaged girders and deck was completed in tandem with material preparation. C.9.4.2 DesignIt was determined that the best option was to rebuild using the original design of the bridge, whichincluded steel girders (Bai and Kim 2007). The original shop drawings of the girders were located by PennDOT and sent to the manufacturer. This accelerated the process as they did not have to reapprove the drawings. Updates to code and other standards were waived by PennDOT, as the original design was deemed ‘sound’ and followed proper engineering judgement. Furthermore, the time-based specifications for concrete maturity and bottom rebar ties were waived (Bai, Burkett, and Nash 2006). C.9.4.3 ProcurementTypically, the steel manufacturer would take upwards of 3-4 weeks to complete a similar project, but thefabricator worked in 24 hour shifts to complete the order in 10 days. The fabricator constructed nine, 65-80’ long girder segments. Each were 6’-8” tall and weighed 15-20 tons. To assist the fabricator and speed

1 5 7u p t h e m a n u f a c t u r i n g p r o c e s s , P e n n D O T c h a n g e d t h e i r r o u t i n e p r o c e d u r e s a n d c o n d u c t e d t h e r e q u i r e di n s p e c t i o n s a t t h e s t e e l p l a n t a n d a t t h e f a b r i c a t i o n s h o p ( B a i a n d K i m 2 0 0 7 ) .C.9.4.4 Permanent StructureT o t r a n s p o r t t h e n e w g i r d e r s t o t h e s i t e , t h e G o v e r n o ro f P e n n s y l v a n i a i s s u e d a p e r m i t t o a l l o w t h em a n u f a c t u r e r t o t r a n s p o r t t h r e e g i r d e r s a t a t i m e . U n d e rn o r m a l C o m m o n w e a l t h l a w , t h e s i z e o f t h e g i r d e r sr e s t r i c t e d l o a d s t o o n l y o n e a t a t i m e ( B a i , B u r k e t t , a n dN a s h 2 0 0 6 ) .A f t e r s e t t i n g t h e g i r d e r s i n p l a c e , s t e e l d e c k p a n sw e r e s e t b e t w e e n t h e m . T h e n , r e i n f o r c i n g b a r s w e r ei n s t a l l e d , a n d t h e 1 0 i n t h i c k d e c k w a s p o u r e d , a s s h o w ni n F i g u r e C - 3 4 . O n c e t h e d e c k w a s c u r e d , t w o l a n e sw e r e m o v e d b a c k t o t h e s o u t h b o u n d s i d e f o r a p a r t i a lr e o p e n i n g o n J u n e 2 5 t h . F r o m t h i s p o i n t , n e w c o n c r e t eb a r r i e r s w e r e a d d e d t o r e p l a c e t h e o l d m e d i a n a n d t h er e s t o f t h e l a n e s w e r e o p e n t o t r a f f i c . R e p a i r w o r k o n t h e m i n o r - d a m a g e d b e n t c o n t i n u e d u n t i l J u l y 3 r d ,w h i c h w a s 1 2 d a y s a h e a d o f s c h e d u l e . T h e t o t a l c o s t o f t h e p r o j e c t w a s $ 4 m i l l i o n , a n d t h e c o n t r a c t o rr e c e i v e d $ 5 0 0 , 0 0 0 i n o v e r t i m e p a y ( B a i , B u r k e t t , a n d N a s h 2 0 0 6 ) .C.9.5 ChallengesT h e e x t r e m e e v e n t o c c u r r e d o v e r M e m o r i a l D a yw e e k e n d , w h i c h i s o n e o f t h e b u s i e s t t r a v e l w e e k e n d s i nt h e n a t i o n . O n a n o r m a l d a y , 8 0 , 0 0 0 v e h i c l e s c r o s s e dt h e C h e s t e r C r e e k B r i d g e , s o t r a f f i c i m p a c t s w e r es i g n i f i c a n t b e f o r e t h e t e m p o r a r y l a n e s c o u l d o p e n ( B a i ,B u r k e t t , a n d N a s h 2 0 0 6 ) .D u r i n g t h i s e x p e d i t e d p r o c e s s , t h e c o m p e t i t i v e b i dp r o c e d u r e w a s o m i t t e d , a n d t h i s w a s c o n s i d e r e d u n f a i rb y o t h e r c o m p a n i e s . T o c r e a t e e q u a l o p p o r t u n i t y a n dm a i n t a i n a s h o r t b i d d i n g p r o c e s s , D O T s s h o u l d h a v e t h ec a p a b i l i t y t o r a p i d l y c r e a t e e m e r g e n c y b i d d i n gp a c k a g e s a n d u s e s t a n d b y e m e r g e n c y c o n t r a c t s .D e v e l o p i n g e m e r g e n c y p r o c e d u r e s a n d p r o t o c o l s t o a i di n t h i s r e s p o n s e c a n h e l p f u t u r e p r o j e c t s ( B a i , B u r k e t t ,a n d N a s h 2 0 0 6 ) .L a s t l y , i t w a s d i f f i c u l t t o e s t i m a t e h o w l o n g i t w o u l dt a k e f o r t h e p r o j e c t t o b e c o m p l e t e d . T h e p r o j e c tf i n i s h e d t w e l v e d a y s a h e a d o f s c h e d u l e , s o t h e o r i g i n a le s t i m a t e s w e r e c o n s e r v a t i v e . B e t t e r l o g g i n g o f p r o g r e s sa n d p r o d u c t i v i t y c a n b e u s e d i n t h e f u t u r e f o r o t h e rD O T s t o m a k e b e t t e r e s t i m a t e s o f p r o j e c t d u r a t i o n , w h i c h c a n h a v e a m a j o r i m p a c t o n r e p a i r m e t h o d s ,d e t o u r s , a n d t e m p o r a r y s t r u c t u r e u s e ( B a i , B u r k e t t , a n d N a s h 2 0 0 6 ) . F i g u r e C - 3 5 s h o w s t h e f i n a l t i m e l i n ef o r t h e p r o j e c t .Figure C-34. Curing of New Deck (Bai, Burkett and Nash 2006)Figure C-35. Timeline of Project (Bai, Burkett, and Nash 2006)

158 C.9.6 Innovations and Lessons LearnedC.9.6.1 Governor Declaration of a State of EmergencyUsing the power of the state Governor was vital to the rapid restoration of this project. From thedeclaration a state of emergency, to issuing special permits for material transport, the Governor of Pennsylvania played a large roll into this project’s success (Bai, Burkett, and Nash 2006). C.9.6.2 Chief Construction Engineer AvailabilityThe PennDOT Chief Construction Engineer was always on site. This prevented the need of a formalrequest or submission for anything that came up during construction and provided another point of contact for asking questions (Bai, Burkett, and Nash 2006). C.9.6.3 Pre-established ContractsUsing established contacts and procedures for emergency situations can help expedite the contractingprocess, which can often be the lengthiest aspect of a project (Bai, Burkett, and Nash 2006). C.9.6.4 Temporary Lane ConstructionTemporary lane construction (or temporary structures if needed) is a very good way to keep trafficflowing. These need to be constructed as soon as possible to be most effective, as detours can cause a litany of problems for infrastructure that was not originally designed for that level of traffic. State Police or other law enforcement can help with traffic control and enforcement of reduced speed limits through work zones (Bai, Burkett, and Nash 2006). C.9.6.5 Centralized Location for Maintaining Bridge DocumentsA centralized location for storing previous bridge plans, design calculations, and inspections can reallyhelp with emergency inspections. Access to accurate and complete plans streamline the design process, and can even be reused, as they were in this case (Bai, Burkett, and Nash 2006). C.9.6.6 Waiving Routine Design ProceduresWaiving certain contracting or design procedures can speed up the repair process. If existing plans arereused, new standards and rules can be waived if the original structure and design was deemed structurally sound (Bai, Burkett, and Nash 2006).

1 5 9C.10 I-29NB Perry Creek Conduit 2019 [Fire]Table C-10. I-29NB Perry Creek Conduit FireCase Study Name/ Date I-29NB Perry Creek Conduit Fire (2019)L ocation Iowa, USAEvent Type FireBridge Name I-29NB Bridge over Perry Creek ConduitScope/ Costs 5/ 8 heavily damaged beams led to total replacement; $ 1 millionPlanning Techniques/ Tools N/ AEvent Response Reduced bridge capacity to 1 laneAssessment Techniques/ Tools V isual assessment, hammer soundingRapid Restoration Type Total replacement Innovations • Nondestructive tests not always required• Fire damage impacts structures of all agesC.10.1 IntroductionT h i s C a s e S t u d y w a s d e v e l o p e d b a s e d o n t h ei n f o r m a t i o n p r o v i d e d b y t h e I o w a D e p a r t m e n t o fT r a n s p o r t a t i o n ( I D O T ) i n t h e Q u e s t i o n n a i r e . T h ei n f o r m a t i o n w a s s u p p l e m e n t e d b y m e d i a s o u r c e d b yD e c k e r t 2 0 1 9 , H D R 2 0 1 9 , H y t r e k 2 0 2 0 , a n d R e n n i e2 0 2 0 .I D O T w a s a l m o s t f i n i s h e d w i t h t h e 1 2 - y e a r l o n g I -2 9 i m p r o v e m e n t p r o j e c t w h e n a f i r e , c a u s e d b y ah o m e l e s s c a m p f i r e , w h i c h i g n i t e d a n e a r b y p r o p a n et a n k , c a u s i n g a n e x p l o s i o n , b r o k e o u t u n d e r t h e I - 2 9 N BP e r r y C r e e k C o n d u i t B r i d g e o n O c t o b e r 3 0 t h , 2 0 1 9( F i g u r e C - 3 6 ) . T h e s i n g l e s p a n b r i d g e c a r r i e d 3n o r t h b o u n d l a n e s o f t r a f f i c a n d h a d b e e n c o m p l e t e do n l y a y e a r b e f o r e ( D e c k e r t 2 0 1 9 ) . 8 c o n c r e t e b e a m sm a d e u p t h e s u p e r s t r u c t u r e , a n d t h r e e i n t e r i o r g i r d e r ss u f f e r e d s e v e r e d a m a g e , a n d t w o w i t h s o m e d a m a g eb e c a u s e o f t h e f i r e ( H D R 2 0 1 9 ) . I D O T h o p e d t h e r e p a i rw o u l d t a k e u n d e r a m o n t h , b u t a c o n s u l t a n t i n v e s t i g a t i o n r e v e a l e d t h e e x t e n s i v e d a m a g e t o t h e i n t e r i o rg i r d e r s – c a u s i n g t h e s t r u c t u r e t o b e u l t i m a t e l y r e p l a c e d . I t s c o m p l e t i o n m a r k e d t h e e n d o f t h e I - 2 9i m p r o v e m e n t p r o j e c t ( D e c k e r t 2 0 1 9 a n d R e n n i e 2 0 2 0 ) .C.10.1.1 Event ResponseO n c e t h e f i r e w a s p u t o u t , t h e a i r q u a l i t y u n d e r t h e b r i d g e w a s f i r s t v e r i f i e d b y l o c a l f i r e c r e w s t o p e r m i ta c c e s s t o i n s p e c t i o n t e a m s . A f t e r a b r i e f i n s p e c t i o n , t h e b r i d g e w a s s o o n r e o p e n e d t o o n e l a n e o f t r a f f i ca c r o s s t h e b r i d g e ( o v e r t h e m i n o r l y d a m a g e d b e a m s ) . B e f o r e t h e I o w a D O T c o u l d o p e n a s e c o n d l a n e , t h es t r u c t u r a l c a p a c i t y w a s t e s t e d w i t h a n i n - h o u s e l o a d r a t i n g ( H D R 2 0 1 9 ) . D u r i n g t h e r e p l a c e m e n t p r o c e s s ,t r a f f i c w a s e v e n t u a l l y r e r o u t e d t o t h e s o u t h b o u n d b r i d g e , w i t h t w o l a n e s i n e a c h d i r e c t i o n ( H y t r e k 2 0 2 0 ) .Figure C-36. Fire Damage to I-29NB Perry Creek Conduit Bridge (Used with permission © Iowa Department of Transportation, HDR 2019)

1 6 0T h e b r i d g e w a s a l s o i n s t r u m e n t e d t o g a t h e r d e f l e c t i o n m e a s u r e m e n t s d u r i n g c o n d u c t e d l o a d t e s t s . T h e s et e s t s w e r e p e r f o r m e d b y t h e I o w a S t a t e U n i v e r s i t y I n s t i t u t e f o r T r a n s p o r t a t i o n B r i d g e E n g i n e e r i n g C e n t e r( P h a r e s e t a l . n . d . ) .C.10.2 Emergency PlanningC.10.2.1 Crowdsourcing and Information GatheringF i r e d a m a g e i s a r e l a t i v e l y u n k n o w n a s p e c t w i t h i n b r i d g e e n g i n e e r i n g . T h e r e a r e c u r r e n t l y a l a c k o fs t a n d a r d s a n d g u i d a n c e f o r h o w t o p l a n a n d a s s e s s s t r u c t u r e s d a m a g e d b y f i r e . H o w e v e r , f i r e d o e s n o t o c c u ra s f r e q u e n t l y a s o t h e r t y p e s o f e m e r g e n c y e v e n t s , s u c h a s c o l l i s i o n s , s o m a n y t r a n s p o r t a t i o n a g e n c i e s , s u c ha s I o w a , a r e n o t w e l l - v e r s e d i n p l a n n i n g o f t h e s e s i t u a t i o n s . F i g u r e C - 3 7 s h o w s t h e e x t e n t o f t h e d a m a g ec a u s e d b y t h e f i r e .C.10.3 AssessmentT h e I o w a D O T h i r e d a c o n s u l t a n t t o a i d i n t h e a s s e s s m e n t o f t h e f i r e d a m a g e d s t r u c t u r e . T o a s s e s s t h ed a m a g e c a u s e d b y t h e f i r e , a v i s u a l i n s p e c t i o n w a s f i r s t c o m p l e t e d , f o l l o w e d b y s o u n d i n g o f t h e c o n c r e t eFigure C-37. CAD Drawing Showing Damaged Beams of the Bridge (Used with permission © Iowa Department of Transportation, HDR 2019) BAFigure C-38. Fire Damage (Used with permission © Iowa Department of Transportation, HDR 2019) (A) Stay-in-Place Construction Forms and Cross Bracing (B) Spalled Concrete

1 6 1s u r f a c e s t o c h e c k f o r d e l a m i n a t i o n s . T h e v i s u a l a s s e s s m e n t w a s u s e d t o i n v e s t i g a t e m i s a l i g n m e n t o f t h eb e a m s , s a g , m e l t i n g o f c r o s s s u p p o r t s , a n d a d e t a i l e d l o o k o f t h e e x p o s e d p r e s t r e s s i n g a n d r e i n f o r c e m e n ts t r a n d s ( F i g u r e C - 3 8 ) . N o n d e s t r u c t i v e t e s t i n g w a s n o t c o n d u c t e d i n t h e i n v e s t i g a t i o n . P e t r o g r a p h i c t e s t i n gw a s c o n s i d e r e d b u t w a s t h o u g h t t o b e t o o t i m e - c o n s u m i n g a n d n o t a v i a b l e o p t i o n d u e t o t h e l a y o u t w i t ht h e b e a m f l a n g e s ( H D R 2 0 1 9 ) .T h e b r i d g e w a s e a s i l y a c c e s s i b l e f r o m t h e g r o u n d , s o o n l y a n e l e c t r i c l i g h t a n d a p o r t a b l e g e n e r a t o r w e r er e q u i r e d t o h e l p i l l u m i n a t e t h e i n s p e c t i o n . S n o o p e r s a n d o t h e r e q u i p m e n t w e r e n o t n e e d e d ( H D R 2 0 1 9 ) .T h e i n s p e c t i o n f o u n d s e v e r e s p a l l i n g a n d d e l a m i n a t e d c o n c r e t e o f 5 c o n c r e t e b e a m s , w i t h n o t i c e a b l er e m a i n i n g c a m b e r i n l i g h t l y d a m a g e d b e a m s . F r o m t h e s e o b s e r v a t i o n s , t h e c o n s u l t a n t r e c o m m e n d e d t h eI o w a D O T r e s t r i c t e d t r a f f i c t o t h e m i n o r l y d a m a g e d p o r t i o n s u n t i l t h e c a p a c i t y o f t h e h e a v i l y d a m a g e dr e g i o n c o u l d b e v e r i f i e d . T o t a l r e p l a c e m e n t o f a l l d a m a g e d b e a m s w a s a l s o r e c o m m e n d e d . T h e d a m a g en o t e d w a s d e t e r m i n e d t o b e c a u s e d b y h e a t r a t h e r t h a n b l a s t a n d w a s m o s t l y c o n c e n t r a t e d a t t h e f l a n g er e g i o n s o f t h e b e a m s ( H D R 2 0 1 9 ) . L a s t l y , t h e c o n s u l t a n t r e c o m m e n d e d t h e b r i d g e u n d e r g o a l o a d r a t i n g t od e t e r m i n e t h e r e m a i n i n g c a p a c i t y i n t h e h e a v i l y d a m a g e d b e a m s , a l s o w i t h l o n g - t e r m s t r u c t u r a l m o n i t o r i n g( H D R 2 0 1 9 ) . I o w a D O T h i r e d t h e I o w a S t a t e U n i v e r s i t y I o w a S t a t e U n i v e r s i t y I n s t i t u t e f o r T r a n s p o r t a t i o nB r i d g e E n g i n e e r i n g C e n t e r t o p e r f o r m a s e r i e s o f f i e l d l o a d t e s t s . T h e b r i d g e w a s i n s t r u m e n t e d w i t h B D Is t r a i n g a g e s l o n g a t m i d s p a n a n d q u a r t e r p o i n t s a l o n g e a c h g i r d e r . S i x l o a d c a s e s c e n a r i o s w e r e t e s t e d , a n da l o a d d i s t r i b u t i o n f a c t o r ( D F ) w a s c a l c u l a t e d f o r e a c h l o a d c a s e . T h e r e s u l t s i n d i c a t e d t h a t 2 o f t h e 8 g i r d e r sh a d a D F g r e a t e r t h a n t h e i r o r i g i n a l A A S H T O d e s i g n . T h e s e g i r d e r s w e r e t h e o n e s w i t h t h e m o s t v i s i b l ed a m a g e a n d w e r e l o c a t e d t o w a r d t h e m i d d l e o f t h e b r i d g e ( P h a r e s e t a l . n . d . ) . T h i s i n f o r m a t i o n w a s a l s o t om a k e t h e r e s t o r a t i o n d e s i g n d e c i s i o n .C.10.4 Rapid RestorationC.10.4.1 Permanent StructureM o s t o f t h e d a m a g e f r o m t h e f i r e w a s l o c a t e d n e a r t h e c e n t e r o f t h e b r i d g e ( F i g u r e C - 3 9 A ) . B e c a u s e o ft h i s l o c a t i o n a n d t h e s e v e r i t y o f t h e d a m a g e , i t w a s d e t e r m i n e d a t o t a l r e p l a c e m e n t w a s t h e b e s t o p t i o n , a so p p o s e d t o r e p a i r i n g t h e d a m a g e d b e a m s , a s s h o w n i n F i g u r e C - 3 9 B ( H y t r e k 2 0 2 0 ) .T h e o r i g i n a l b r i d g e , c o n s t r u c t i o n a y e a r b e f o r e , c o s t $ 8 0 0 , 0 0 0 . H o w e v e r , t h e r e p l a c e m e n t a f t e r t h e f i r et o t a l e d $ 1 m i l l i o n . T h e p r o j e c t s t a r t e d i n M a r c h o f 2 0 2 0 a n d w r a p p e d u p i n J u l y ( R e n n i e 2 0 2 0 ) .A BFigure C-39. Permanent Structure (A) Plan View of Damaged Bridge Portions (Used with permission © Iowa Department of Transportation, HDR 2019) (B) Replacement of Bridge (Hytrek 2020)

162 C.10.5 ChallengesOne of the challenges with the fire damage was the unknown impact on the bridge’s remaining structuralcapacity. Bridges are not typically designed with fire resistance in mind, and even though the bridge was brand new, it still was highly susceptible to the high heat and blasts caused by the exploding propane tanks. Understanding the extent of the damage required IDOT to hire a consultant to assess the fire-related damages to help decide the fate of the structure. Additionally, the fire took place right as the I-29 improvement project was wrapping up. Commuters and motorists were once again disrupted due to the restricted traffic flow across the bridge and other construction in the region. The fire did create a several-month setback and was frustrating to the public. C.10.6 Innovations and Lessons LearnedC.10.6.1 Nondestructive Test not always RequiredIn the case of I-29NB Bridge’s assessment, nondestructive tests were deemed unnecessarily. The extentof damage was able to be observed with a visual assessment only, and deflections and changes in camber were recorded. Nondestructive testing was not required to make a full observation of damage, and the best assessment came from a load rating of the bridge, which included the effects of the damaged members (HDR 2019). C.10.6.2 Age of Bridge Not a Determinant of Fire DamageThe I-29NB Bridge had been completed only a year before the fire. Even with current design standards,the structure still required a total replacement. Often, bridge damage correlates to the age of the structure when it comes to other emergency events. However, even if the current engineering specifications, fire can leave a devastating impact, and effects structures of all ages.

1 6 3C.11 Glenn Highway and Eagle River Overpass 2018 [Collision]Table C-11. Glenn Highway and Eagle River Overpass Collision Case Study Name/ Date Glenn Highway and Eagle River Overpass Collison (2018 )L ocation Alaska, USAEvent Type CollisionBridge Name Eagle River Overpass Scope/ Costs Immediate Repairs $ 1.5 million, Permanent Repairs $ 1.5 million Planning Techniques/ Tools N/ AEvent Response Full closure Assessment Techniques/ Tools V isual assessment and unmanned aerial vehicles Rapid Restoration Type Girder removal, eventual replacement Innovations • Structural engineer on site• Temporary girder removal until replacementC.11.1 IntroductionT h i s C a s e S t u d y w a s d e v e l o p e d b a s e d o n t h ei n f o r m a t i o n p r o v i d e d b y t h e A l a s k a D e p a r t m e n t o fT r a n s p o r t a t i o n & P u b l i c F a c i l i t i e s ( A l a s k a D O T & P F )i n t h e Q u e s t i o n n a i r e . T h e i n f o r m a t i o n w a ss u p p l e m e n t e d b y m e d i a s o u r c e d b y L e v i n g s a n dM u r r a y 2 0 1 9 .O n M a r c h 2 1 s t , 2 0 1 8 , a n o v e r h e i g h t c o m m e r c i a lv e h i c l e s t r u c k a p r e s t r e s s e d / p o s t t e n s i o n e d c o n c r e t eg i r d e r o n t h e S o u t h E a g l e R i v e r O v e r p a s s o n t h e G l e n nH i g h w a y i n A n c h o r a g e , A l a s k a . T h e d a m a g e w a s s os e v e r e , i t c a u s e d t h e e n t i r e i n t e r s t a t e i n t e r c h a n g e t o b es h u t d o w n ( F i g u r e C - 4 0 ) . T h e d e s i g n o f t h e i n t e r c h a n g ec r e a t e d l i m i t e dd e t o u r o p t i o n s , c a u s i n g s u b s t a n t i a l t r a f f i c g r i d l o c k . T h e i m p a c t w a s s os i g n i f i c a n t , m a n y s t a t e o f f i c e s a n d o t h e r b u s i n e s s e s i n A n c h o r a g ep a r t i a l l y c l o s e d t o h e l p a l l e v i a t e t h e t r a f f i c l o a d s i n t h e a r e a u n t i l t h ei n t e r c h a n g e r e o p e n e d . A t e m p o r a r y d e t o u r w a s f i n a l l y c r e a t e d u n t i lr e p a i r s c o u l d b e m a d e ( L e v i n g s a n d M u r r a y 2 0 1 9 ) .1.1.2.Event Response T h e i n t e r c h a n g e w a s i m m e d i a t e l y c l o s e d f o l l o w i n g t h e c o l l i s i o n . T w od a y s a f t e r t h e i m p a c t , a d e t o u r w a s c r e a t e d a r o u n d t h e r e g i o n t o h e l pa l l e v i a t e t h e g r i d l o c k u n t i l t h e r o u t e c o u l d b e r e o p e n e d , a s s h o w n i nF i g u r e C - 4 1 . H o w e v e r , t h e d e t o u r s t i l l l e d t o s i g n i f i c a n t b a c k u p s , a t t h eG l e n n H i g h w a y i s t h e m a i n t r a v e l r o u t e i n t o A n c h o r a g e ( L e v i n g s a n dM u r r a y 2 0 1 9 ) .Figure C-40. Collison Damage to Eagle River Overpass (Levings & Murray 2019)Figure C-41. Established Detour Route (Levings & Murray 2019)

1 6 4C.11.2 Emergency PlanningN o e m e r g e n c y p l a n n i n g i n f o r m a t i o n w a s a v a i l a b l e .C.11.3 AssessmentC r e w s u s e d v i s u a l i n s p e c t i o n s a n d u n m a n n e d a e r i a l v e h i c l e s t o a s s e s s t h e b r i d g e . I m m e d i a t e l y f o l l o w i n gt h e c o l l i s i o n , p h o t o s w e r e c o l l e c t e d t o i d e n t i f y t h e d a m a g e d p o r t i o n s o f t h e i m p a c t e d g i r d e r . F r o m t h e v i s u a la s s e s s m e n t , i t w a s d e t e r m i n e d t h e i n t e r c h a n g e w a s u n a b l e t o b e r e o p e n e d u n t i l r e p a i r s c o u l d b e m a d e .B e c a u s e o f t h i s , s u b s t a n t i a l t r a f f i c c o n t r o l w a s d e p l o y e d . I n t o t a l , 3 1 s t i r r u p s w e r e e x p o s e d , t h e g i r d e r h a da 4 - i n c h l a t e r a l d e f l e c t i o n , a n d t h e r e w a s a 1 . 5 f t b y 4 f t h o l e a r o u n d t h e p o s t t e n s i o n e d d u c t . T w o e x p o s e ds t i r r u p s w e r e a l s o s h e a r e d ( L e v i n g s a n d M u r r a y 2 0 1 9 ) .C.11.4 Rapid RestorationC.11.4.1 ContractingT o l e a d t h e p r o j e c t , t h e A l a s k a D O T & P F s e n t a s t r u c t u r a l e n g i n e e r t o A n c h o r a g e , a n d s e l e c t e d a ne m e r g e n c y p r o j e c t e n g i n e e r , w h o l i v e d n e a r t h e s i t e a n d h a d p r e v i o u s e x p e r i e n c e w i t h a s i m i l a r b r i d g ei m p a c t . T h e s a m e d a y o f t h e c o l l i s i o n , t h e o n - s i t e s t r u c t u r a l e n g i n e e r d e t e r m i n e d t h e s e v e r e l y d a m a g e dg i r d e r n e e d e d t o b e r e m o v e d . T h i s c o n c l u s i o n w a s m a d e 1 0 h o u r s a f t e r t h e c o l l i s i o n o c c u r r e d . T h e n e x tm o r n i n g , A l a s k a D O T & P F s e l e c t e d a c o n t r a c t o r f o r t h e r e p a i r s , a n d w a s t a s k e d w i t h p r o v i d i n g e q u i p m e n t ,a m a t e r i a l s l i s t , a n d p e r s o n n e l f o r t h e p r o j e c t ( L e v i n g s a n d M u r r a y 2 0 1 9 ) .C.11.4.2 DesignT h e o n - s i t e s t r u c t u r a l e n g i n e e r h e l p e d d e v e l o p o n t h e s p o ts o l u t i o n s f o r t h e r e p a i r . T h e y w e r e r e s p o n s i b l e f o rc o m p l e t i n g f i e l d c a l c u l a t i o n s t o d e t e r m i n e t h e g i r d e rc a p a c i t y , a v a i l a b l e e q u i p m e n t l o a d s , a n d v e r i f y t h e b r i d g e ’ sr e m a i n i n g c a p a c i t y u s i n g p i c k l o a d s . A d d i t i o n a l l y , t h e yh e l p e d d e v e l o p t h e g i r d e r r e m o v a l p l a n ( L e v i n g s a n dM u r r a y 2 0 1 9 ) .C.11.4.3 Temporary StructureA s p a r t o f t h e t e m p o r a r y r e p a i r , t h e d a m a g e d g i r d e r w a sr e m o v e d f o u r d a y s a f t e r t h e c o l l i s i o n . T h i s p e r m i t t e d t h ei n t e r s t a t e t o r e o p e n t h e f o l l o w i n g d a y , f i v e d a y s a f t e r t h ec o l l i s i o n . U n t i l t h e f i n a l r e p a i r s c o u l d b e m a d e ( t w o y e a r sl a t e r ) , t h e i n t e r c h a n g e h a d a l a n e r e s t r i c t i o n .O n d a y 3 , t h e b r i d g e w a s s h o r e d u s i n g w o o d e d - l i k ep a l l e t s c a l l e d c r i b b i n g ( F i g u r e C - 4 3 ) . B e c a u s e t h e g i r d e rw a s s o h e a v i l y d a m a g e d , a m u l t i - s t e p p r o c e s s w a su n d e r t a k e n t o s a f e l y r e m o v e t h e g i r d e r t o a v o i d b u c k l i n g .W i t h t h e c r i b b i n g i n p l a c e o n e a c h s i d e o f t h e d a m a g e da r e a , h o l e s w e r e c o r e d t h r o u g h t h e d e c k a n d g i r d e r t o pf l a n g e t o c r a c k a l i f t i n g l o c a t i o n f o r t h e c r a n e s ( F i g u r e C -4 2 ) . T h e c r a n e s t h e n l i f t e d t h e g i r d e r u p j u s t e n o u g h t oc a r r y t h e d e a d l o a d . T h e n , t h e g l i d e r w a s c u t l o n g i t u d i n a l l yFigure C-42. Girder Removal Cut Plan 71102 (Levings & Murray 2019)Figure C-43. Temporary Shoring Required for Girder Removal (Levings & Murray 2018)

1 6 5t o d i s c o n n e c t i t f r o m t h e a d j a c e n t g i r d e r . T o c o m p l e t e l y s e v e r t h e g i r d e r i n t o t w o h a l v e s , t h e d a m a g e d a r e aw a s p i c k e d a t w i t h a n e x c a v a t o r , a n d t h e n t h e t w o h a l v e s o f t h e g i r d e r w e r e l i f t e d a w a y s e p a r a t e l y ( F i g u r eC - 4 5 ) . T h i s p r o c e s s t o o k p l a c e o v e r a f e w d a y s , a n d b y d a y 5 , t h e g i r d e r r e m o v a l w a s c o m p l e t e , a n d t h er e g i o n w a s c l e a n e d u p ( F i g u r e C - 4 4 ) . B y 1 0 p m o n d a y 5 , t h e b r i d g e w a s a b l e t o b e r e o p e n e d t o t r a f f i c u n t i lp e r m a n e n t r e p a i r s w e r e b u i l t i n 2 0 2 0 ( L e v i n g s a n d M u r r a y 2 0 1 9 ) .C.11.4.4 Permanent StructureI n 2 0 2 0 , t h e b r i d g e w a s r e b u i l t w i t h n e w r a i l s , s i d e w a l k , a n d i m p r o v e m e n t s t o t h e d i a p h r a g m . I t a l s oi n c l u d e d t h e r e p l a c e m e n t o f t w o e x t e r i o r g i r d e r s , t h e o n e r e m o v e d i n 2 0 1 9 , a n d t h e e x t e r i o r g i r d e r o n t h eo p p o s i t e s i d e o f t h e b r i d g e , w h i c h w a s a l s o d a m a g e d f r o m a p r e v i o u s c o l l i s i o n , t h o u g h t h a t d a m a g e w a s n o td e e m e d e x t r e m e e n o u g h f o r c o m p l e t e r e m o v a l ( F i g u r e C - 4 6 ) ( L e v i n g s a n d M u r r a y 2 0 1 9 ) .Figure C-45. Girder Removal 71104 (Levings & Murray 2019)Figure C-46. Permanent Repair Design (Levings & Murray 2019)Figure C-44. Temporary Repair Clean Up 71106 (Levings & Murray 2019)

166 C.11.5 ChallengesThe strike occurred during winter, which made repairs and work extremely difficult due to the frigidworking environment. Furthermore, the lack of possible detour routes put an added stress on the entire situation, as the section of road had an ADT of 60,000 vehicles a day, making it one of the business roadways in all of Alaska (Levings and Murray 2019). C.11.6 Innovations and Lessons LearnedC.11.6.1 On-Site Structural Engineer for Calculations Expedited ProcessThe availability of a structural engineer onsite expedited the entire process. They were able to makeinstant decisions such as the girder removal plan, capacity calculations, and logistical management that would not be possible without someone present (Levings and Murray 2019). C.11.6.2 Temporary Removal until Permanent RepairsThe decision to remove the girder without the immediate replacement allowed for a quicker reopeningthan if the girder were restored directly following the strike. The overpass was still able to function with one less girder, even though the lane capacity had to be reduced. Furthermore, the Glenn Highway was able to reopen sooner, alleviating the major traffic disruption (Levings and Murray 2019).

1 6 7C.12 Interstate 555 Highway 1B Overpass 2017 [Collision]Table C-12. Interstate 555 Highway 1B OverpassCase Study Name/ Date Interstate 555 Highway 1B Overpass (2017 )L ocation Arkansas, USAEvent Type CollisionBridge Name Highway 1B OverpassScope/ Costs Repairs to columns and deck, total approximately $ 48 4,000Planning Techniques/ Tools N/ AEvent Response Immediate closure of both roadways, erection of temporary structure, with later permanent repairsAssessment Techniques/ Tools V isual Assessment Rapid Restoration Type Temporary supports while replacement of damaged columns took place Innovations • Temporary Supports• In-House transportation repair workC.12.1 IntroductionT h i s C a s e S t u d y w a s d e v e l o p e d b a s e d o n t h ei n f o r m a t i o n p r o v i d e d b y A r k a n s a s D e p a r t m e n t o fT r a n s p o r t a t i o n ( A R D O T ) i n t h e Q u e s t i o n n a i r e . T h ei n f o r m a t i o n w a s s u p p l e m e n t e d b y m e d i a s o u r c e s b yK A R K N e w s 2 0 1 7 a n d A r k a n s a s O n l i n e 2 0 1 7 .O n J u n e 2 7 t h , 2 0 1 7 , a c o m m e r c i a l v e h i c l e c o l l i d e dw i t h t h e H i g h w a y 1 B o v e r p a s s o v e r I n t e r s t a t e 5 5 5 i nJ o n e s b o r o , A r k a n s a s , l e a v i n g e x t e n s i v e d a m a g e t o t h es t r u c t u r e ( F i g u r e C - 4 7 , F i g u r e C - 4 8 , a n d F i g u r e C - 4 9 ) .B o t h t h e i n t e r s t a t e a n d h i g h w a y w e r e c l o s e d b e c a u s e o ft h e c o l l i s i o n . D a m a g e i n c l u d e d h e a v i l y d a m a g e d b r i d g ec o l u m n s , b e n t c a p , a n d c r a c k i n g o f t h e d e c k . At e m p o r a r y b e n t w a s i n s t a l l e d t o r e o p e n t h e i n t e r s t a t e , a n dp e r m a n e n t r e p a i r s w e r e c o m p l e t e d t w o w e e k s a f t e r t h ec o l l i s i o n , r e o p e n i n g H i g h w a y 1 B . T h e e n t i r e r e p a i rp o r t i o n o f t h e p r o j e c t a l o n g w i t h t r a f f i c c o n t r o l c o s ta p p r o x i m a t e l y $ 2 4 7 , 0 0 0 . T h e b r i d g e p a i n t i n g w a s l e t t oc o n t r a c t f o r $ 2 3 7 , 7 0 4 . A l l r e p a i r w o r k w a s c o m p l e t e d b yt h e A r k a n s a s D e p a r t m e n t o f T r a n s p o r t a t i o n ( A R D O T ) .C.12.1.1 Event ResponseB o t h I n t e r s t a t e 5 5 5 a n d H i g h w a y 1 B w e r e i m m e d i a t e l y c l o s e d f o l l o w i n g t h e c o l l i s i o n . O n c e t h et e m p o r a r y s t r u c t u r e w a s e r e c t e d , I n t e r s t a t e 5 5 5 w a sr e o p e n e d H o w e v e r , H i g h w a y 1 B w a s o n l y p a r t i a l l y r e o p e n o n t h e u n d a m a g e d s o u t h s i d e t o t w o - w a y t r a f f i c .Figure C-47. Commercial Vehicle Collision with Intermediate Bent (Arkansas Online 2017)Figure C-48. Damage to Bent (Courtesy of Heavy Bridge Maintenance, ARDOT)

1 6 8I t w a s n o t u n t i l p e r m a n e n t r e p a i r s w e r e c o m p l e t e d t h a t f u l l t r a f f i c w a s p e r m i t t e d o n H i g h w a y 1 B ( K A R K2 0 1 7 ) .C.12.2 Emergency PlanningN o e m e r g e n c y p l a n n i n g i n f o r m a t i o n w a s a v a i l a b l e .C.12.3 AssessmentA v i s u a l a s s e s s m e n t o f t h e s t r u c t u r e r e v e a l e d t h eh e a v i l y d a m a g e d b e n t t h a t t o o k t h e b r u n t o f t h e i m p a c t .T h e f o u r c o l u m n s t h a t m a d e u p t h e b e n t s u s t a i n e ds i g n i f i c a n t d a m a g e , a n d o n e w a s e x t e n s i v e l y d a m a g e d .T h e d a m a g e d b e n t c a u s e d a f e w o f t h e g i r d e r s t o h a v en o i n t e r m e d i a t e s u p p o r t , c a u s i n g t h e s t r u c t u r e t o s a g .I m m e d i a t e l y f o l l o w i n g t h e c o l l i s i o n , i t w a s u n c l e a r i ft h e s t r u c t u r e w a s i n j e o p a r d y o f c o l l a p s i n g ; h o w e v e r ,f u r t h e r i n v e s t i g a t i o n i n d i c a t e d t h e o v e r p a s s w a s n o t i nd a n g e r o f c o l l a p s e ( A r k a n s a s O n l i n e 2 0 1 7 ) .C.12.4 Rapid RestorationC.12.4.1 Temporary StructureT h e c l o s u r e o f b o t h r o a d w a y s i m p a c t e d a b o u t 4 3 , 0 0 0 v e h i c l e s a d a y , s o a t e m p o r a r y r e p a i r w a s o f t h eu t m o s t i m p o r t a n c e . T o t e m p o r a r i l y s t a b i l i z e t h e s t r u c t u r e , c r e w s f r o m A R D O T ’ s H e a v y B r i d g eM a i n t e n a n c e s e c t i o n ( H B M ) a r r i v e d w i t h i n h o u r s o f t h e c o l l i s i o n . T h e y i n s t a l l e d a t e m p o r a r y w o o d e n b e n t ,w h i c h a l l o w e d f o r I n t e r s t a t e 5 5 5 t o o p e n t h e f o l l o w i n g d a y ( F i g u r e C - 5 0 A & B ) . T h e t e m p o r a r y s t r u c t u r ec o n s i s t e d o f a s t e e l b e a m c a p h e l d u p b y a t i m b e r b r a c e d s y s t e m . J a c k s w e r e p l a c e d o n t o p o f t h e c a p t os u p p o r t t h e o v e r p a s s , w h i c h a l l o w e d w o r k e r s t o r e m o v e a n d r e p l a c e t h e d a m a g e d b e n t ( K A R K 2 0 1 7 ) .C.12.4.2 Permanent StructureT h e p e r m a n e n t r e p a i r s r e q u i r e d c r e w s t o w o r k m o s t l y a r o u n d t h e c l o c k . H i g h w a y 1 B w a s f u l l y o p e n e do n J u l y 1 0 t h , t w o w e e k s a f t e r t h e c o l l i s i o n . T h e p e r m a n e n t s t r u c t u r e c o n s i s t s o f a n e w i n t e r m e d i a t e b e n t( F i g u r e C - 5 0 C ) . T h e f o u r s t e e l m a i n g i r d e r s w e r e f o u n d t o n o t r e q u i r e r e p l a c e m e n t o r s p l i c i n g ( K A R K2 0 1 7 ) .Figure C-49. Damage to Bent (Courtesy of Heavy Bridge Maintenance, ARDOT)

1 6 9C.12.5 ChallengesT h e c l o s u r e c a u s e d a s i g n i f i c a n t t r a f f i c b a c k l o g , a s u p w a r d s o f 4 3 , 0 0 0 v e h i c l e s u s e t h i s s t r e t c h o fh i g h w a y / i n t e r s t a t e d a i l y . T o r e d u c e t h e i m p a c t o n c o m m u t e r s , t h e t e m p o r a r y s t r u c t u r e w a s i n s t a l l e d ( F i g u r eC - 5 0 D ) .C.12.6 Innovations and Lessons LearnedC.12.6.1 Temporary Structure for Partial ReopeningE v e n t h o u g h r e p a i r s w e r e c o m p l e t e d i n t w o w e e k s , k e e p i n g I n t e r s t a t e 5 5 5 c l o s e d f o r t h a t l e n g t h o f t i m ew o u l d b e t o o c o s t l y t o m o t o r i s t s . U s i n g t h e t e m p o r a r y s t r u c t u r e i n t a n d e m w i t h c o n s t r u c t i o n o n p e r m a n e n tr e p a i r s p e r m i t t e d t h e r e o p e n i n g o f I n t e r s t a t e 5 5 5 s o o n e r a n d e x p e d i t e d t h e e n t i r e r e p a i r p r o c e s s .BADCFigure C-50. Temporary Structure (Courtesy of Heavy Bridge Maintenance, ARDOT) (A) Assembly of Temporary Bent (B) Beginning Construction Stages of Temporary Bent (C) New Bent Forms (D) Temporary Bent

170 C.12.6.2 In-House CompletionBesides painting, all repairs, including the temporary support and column replacement was completed bythe Arkansas DOT. In Arkansas, repairs are generally performed by in-house crews. Arkansas’s Heavy Bridge Maintenance crews worked in tandem with District 10 Maintenance crews to take care of the repairs themselves. This saved time by omitting bidding and contracting procedures.

1 7 1C.13 Arkansas River Bridge Collapse 2002 [Collision]Table C-13. Arkansas River Bridge Collapse Case Study Name/ Date Collapse of I-40 Arkansas River Bridge (2002)L ocation Arkansas, USAEvent Type CollisionBridge Name I-40 Webbers Fall BridgeScope/ Costs 58 0’ bridge section collapsed; total cost $ 30 millionPlanning Techniques/ Tools N/ AEvent Response Detours and detour route improvementsAssessment Techniques/ Tools Non-linear pushover analysis using softwareRapid Restoration Type Precast componentsInnovations • Use of prestressed precast girders• Heat straighteningC.13.1 IntroductionO n M a y 2 6 t h , 2 0 0 2 , a t o w b o a t p u l l i n g t w o e m p t yb a r g e s c o l l i d e d i n t o t h e I - 4 0 W e b b e r s F a l l B r i d g e o nt h e A r k a n s a s R i v e r a f t e r t h e b o a t o p e r a t o r s u f f e r e d am e d i c a l e p i s o d e , w h i c h c a u s e d h i m t o b l a c k o u t( G e o r g i a T e c h R e s e a r c h C o r p o r a t i o n e t a l . 2 0 1 2 ) . T h ec o l l i s i o n r e s u l t e d i n t h e c o l l a p s e o f f o u r b r i d g e s p a n sa n d t h e a d j a c e n t p i e r s i n t o t h e A r k a n s a s R i v e r d e p i c t e di n F i g u r e C - 5 1 . R e s c u e d i v e r r e s p o n s e t e a m s w e r ed e p l o y e d f o l l o w i n g t h e c o l l a p s e a n d t h e e v e n t r e s u l t e di n a t o t a l o f f o u r t e e n d e a t h s ( F H W A 2 0 0 2 ) . T oe x p e d i t e t h e r e o p e n i n g o f t h e b r i d g e , b r i d g e e n g i n e e r sc h o s e t o r e p l a c e t h e s p a n s w i t h p r e s t r e s s e d , p r e c a s tc o n c r e t e g i r d e r s a n d a s i n g l e s t e e l s p a n t o t i e i n t o t h ee x i s t i n g s t e e l s t r u c t u r e . T h e I - 4 0 W e b b e r s F a l l s B r i d g ew a s r e o p e n e d t o t r a f f i c j u s t s i x t y - f o u r d a y s a f t e r t h ec o l l i s i o n ( B a i a n d K i m 2 0 0 7 ) .C.13.1.1 Event ResponseI m m e d i a t e l y f o l l o w i n g t h e c o l l i s i o n , t h e O k l a h o m a H i g h w a y P a t r o l , a n d t h e U n i t e d S t a t e s C o a s t G u a r d( U S C G ) a s s i s t e d i n t h e r e c o v e r y o f v e h i c l e s a n d v i c t i m s o f t h e b r i d g e c o l l a p s e . R e m a i n i n g s e c t i o n s o f t h eW e b b e r s F a l l s B r i d g e w e r e s t a b i l i z e d t o e n s u r e s a f e t y d u r i n g t h e s e r e c o v e r y e f f o r t s . T h e c o n t r a c t o r s e l e c t e df o r t h e r e p a i r s h a d s o m e o f i t s c o n s t r u c t i o n c r e w w o r k i n g d o w n r i v e r a t a n e a r b y p r o j e c t a n d w a s a b l e t oq u i c k l y m o v e e q u i p m e n t a n d w o r k e r s u p s t r e a m t o a s s i s t i n b r i d g e d e m o l i t i o n a n d r e s t o r a t i o n ( W i m m e r2 0 0 4 ) .W i t h o u t t h e I - 4 0 W e b b e r s F a l l s B r i d g e c r o s s i n g , d a i l y c o m m u t e r s a n d t r u c k t r a f f i c h a d a n u r g e n t n e e df o r t r a f f i c d e t o u r s a c r o s s t h e A r k a n s a s R i v e r n e a r t h e c o l l a p s e d b r i d g e s i t e . O k l a h o m a D O T o f f i c i a l sf u n n e l e d t r a f f i c o n t o e x i s t i n g a l t e r n a t e r o u t e s ; h o w e v e r , t h e s e h i g h w a y s a n d a r t e r i a l s w e r e n o t b u i l t t o c a r r ys u c h h e a v y v e h i c u l a r t r a f f i c . A s a r e s u l t , t h e O k l a h o m a D O T c o m p l e t e d s e r i o u s m a i n t e n a n c e o n t h e s eFigure C-51. Collapse of I-40 Webbers Bridge (Georgia Tech Research Corporation et al.2012)

172 detour roadways such as overlays and pavement resurfacing. The Oklahoma DOT also inspected forty-two bridges along the detours and performed maintenance on two of the bridges to sustain the new temporary traffic volume (Bai and Kim 2007). A total of twelve million dollars was spent on roadway surface enhancements and railroad crossing improvements along the detour routes resulting from the Webbers Falls Bridge collapse (FHWA 2002). C.13.2 Emergency PlanningC.13.2.1 Crowdsourcing and Information GatheringLocal news outlets touched on the general response efforts and traffic detours that took place immediately following the bridge collapse. Because the event took place in 2002, there were no social media outlets reporting on the event. Social media may have been a more efficient way of communicating traffic detour routes immediately following the event to reduce route confusion. This event relied on local news outlets such as Tulsa World News for sharing current information to the public (Tulsa World 2016). C.13.3 AssessmentA consultant group of forensic engineers and professional engineering divers investigated the damage tothe foundation and submerged substructure of the bridge following the collision. The engineers used in-house software to assess the damage following the investigation. A non-linear pushover analysis was used to construct the events leading up to the collision. An in-house specialist created a video demonstrating a live simulation of the collapse using data from the investigation reports (McLaren Engineering Group 2020). C.13.4 Rapid RestorationC.13.4.1 ContractingA week after the collision, a pre-bid meeting was held, and all potential contractors were invited. Thismeeting took place without a complete set of bridge plans. Seventeen days after the collision, the contract was awarded. Designers had the plans ready sixteen days following the pre-bid meeting and construction went underway (FHWA 2002). To promote rapid bridge restoration, the Oklahoma DOT called for A+B Bidding and an incentive/disincentive clause (I/D) for demolition ($50k/day), design ($5k/day), and construction ($6k/hour) contracts. As a result, the demolition was completed four days early, and the construction was completed two-hundred and forty-eight hours early (Bai and Kim 2007). The Oklahoma DOT built relationships with key organizations affected by bridge construction. These relationships were key to the success of rapid bridge restoration and distribution of heavy traffic volumes to nearby routes. Much of the land surrounding the I-40 Webbers Falls Bridge, including alternate traffic routes, belonged to the Cherokee Nation. Coordination took place between the tribal government and Oklahoma DOT to allow for ease of bridge access for construction vehicles and equipment through Cherokee Nation land. Another key contributor, the FHWA, provided emergency relief funds, technical guidance, and contract assistance during the bridge restoration process. Additional contributions to project success included technical advice provided by the USCG, US Army Corps, and Caltrans (FHWA 2002).

1 7 3C.13.4.2 Design I n s t e a d o f s t i c k i n g t o t h e o r i g i n a l s t e e l d e s i g n o f t h eb r i d g e , t h e O k l a h o m a D O T d e c i d e d t o r e p l a c e t h ed a m a g e d s p a n s w i t h t h r e e p r e s t r e s s e d , p r e c a s t c o n c r e t eg i r d e r s . T h e O k l a h o m a D O T c h o s e t h i s t e c h n i q u e t or e d u c e t h e t i m e n e e d e d f o r b r i d g e r e p a i r s ( B a i a n d K i m2 0 0 7 ) . B r i d g e e n g i n e e r s c h o s e t o d e s i g n o n e s t e e lb r i d g e s p a n t o t i e t h e p r e s t r e s s e d , p r e c a s t c o n c r e t es p a n s i n t o t h e e x i s t i n g s t e e l s t r u c t u r e . T h e y a l s or e c o n s t r u c t e d t h e d a m a g e d p i e r s , a s s h o w n i n F i g u r e C -5 2 . T o m o n i t o r t h e c u r i n g o f t h e c o n c r e t e s e c t i o n s , t h ec o n t r a c t o r u s e d c o m p u t e r c h i p s t o m e a s u r e t h e t e m p e r a t u r e o f t h e s e t t i n g c o n c r e t e ( F H W A 2 0 0 2 ) .C.13.4.3 Permanent StructureC o n t r a c t o r s u s e d h e a t - s t r a i g h t e n i n g t o r e p a i r e x i s t i n g d a m a g e d s p a n s t h a t d i d n o t c o l l a p s e i n t o t h e r i v e r .H e a t - s t r a i g h t e n i n g i n v o l v e s r e p e a t e d l y a p p l y i n g s m a l l a m o u n t s o f h e a t t o t h e d a m a g e d r e g i o n s t o i n c r e a s et h e w o r k a b i l i t y o f t h e m a t e r i a l a n d t o e n a b l e e a s i e r s t r a i g h t e n i n g o f t h e s t e e l g i r d e r s ( F H W A 2 0 0 2 ) .D u r i n g t h e c o n s t r u c t i o n p r o c e s s , t h e O k l a h o m a D O T A s s i s t a n t B r i d g e E n g i n e e r w a s o n c a l l 2 4 / 7 t o h e l pa n s w e r q u e s t i o n s o r i s s u e s t h a t a r o s e d u r i n g c o n s t r u c t i o n a n d k e p t t h e p r o j e c t o n s c h e d u l e . F u r t h e r m o r e ,t h e D O T d e v e l o p e d a t h i r t e e n - p e r s o n i n s p e c t i o n t e a m t o o v e r s e e t h e c o n s t r u c t i o n . S o m e o f t h e s e t e a mm e m b e r s c o n s i s t e d o f r e t i r e d O k l a h o m a D O T i n s p e c t o r s o r e m p l o y e e s . I n s p e c t o r s a l s o s u p e r v i s e d t h e s t e e lm a n u f a c t u r i n g t o e n s u r e p r o p e r Q A Q C . T o g i v e s o m e p e r s p e c t i v e , t y p i c a l l y t w o i n s p e c t o r s a r e u s e da l t o g e t h e r f o r a r e g u l a r p r o j e c t o f t h i s m a g n i t u d e ( B a i a n d K i m 2 0 0 7 ) .C.13.5 ChallengesS c h e d u l i n g a n d c o s t e s t i m a t i n g a r e d i f f i c u l t t a s k s i ne m e r g e n c y s i t u a t i o n s s u c h a s t h e I - 4 0 W e b b e r s F a l l sB r i d g e c o l l a p s e a n d r e c o n s t r u c t i o n p r o c e s s . A t p r o j e c tc o m p l e t i o n , t h e f i n a l c o s t s a s s o c i a t e d w i t h b r i d g er e c o n s t r u c t i o n w e r e d o u b l e t h e o r i g i n a l c o s t e s t i m a t e ,b u t t h e p r o j e c t w a s f i n i s h e d t e n m o n t h s s o o n e r t h a no r i g i n a l l y p r e d i c t e d . T h e u s e o f t e c h n o l o g y s u c h a si P a d s a n d l a p t o p s c a n b e t t e r m o n i t o r c o n s t r u c t i o ne f f i c i e n c y a n d p r o g r e s s . C a m e r a s w e r e u s e d t o c a p t u r e ,d o c u m e n t , i n s p e c t , a n d m o n i t o r t h e r e s t o r a t i o n p r o c e s so f t h e I - 4 0 W e b b e r s B r i d g e f o l l o w i n g t h e c o l l a p s e .A c c e s s t o c u r r e n t i n f o r m a t i o n o n b r i d g e r e s t o r a t i o n c a nb e u s e d t o k e e p c o s t e s t i m a t e s a n d s c h e d u l i n g c u r r e n tt h r o u g h o u t t h e b r i d g e r e s t o r a t i o n p r o c e s s ( B a i a n d K i m 2 0 0 7 ) . F i g u r e C - 5 3 s h o w s t h e c o m p l e t e d b r i d g es t r u c t u r e .D u r i n g t h e c o l l i s i o n , s o m e o f t h e p i e r s w e r e d a m a g e d a n d n e e d e d t o b e r e p l a c e d . D e m o l i t i o n o f t h es u b m e r g e d s e c t i o n s o f t h e d a m a g e d p i e r s w a s d i f f i c u l t . F u t u r e r e s e a r c h s h o u l d b e c o n d u c t e d t o d e t e r m i n et h e m o s t e f f i c i e n t a n d s a f e s t m e t h o d s f o r a c h i e v i n g u n d e r w a t e r d e m o l i t i o n . M o r e a d v a n c e d u n d e r w a t e rd e m o l i t i o n t e c h n i q u e s , i f k n o w n , c o u l d h a v e r e d u c e d t h e t i m e r e q u i r e d t o r e p l a c e t h e s u b m e r g e d p i e r s a n de n s u r e t h e s a f e t y o f c r e w s w o r k i n g o n t h e I - 4 0 W e b b e r s F a l l s B r i d g e ( B a i a n d B u r k e t t 2 0 0 6 ) .Figure C-52. Reconstruction of Piers (FHWA 2002)Figure C-53. Completed Repairs (FHWA 2012)

174 C.13.6 Innovations and Lessons LearnedC.13.6.1 Repair Methods Should Consider Economic ConsequencesThe I-40 Webbers Falls Bridge is a major east-west commerce route. The cost of keeping the bridgeclosed had extreme economic consequences. Maintenance of the fifty-seven-mile-long eastbound detour and six-mile-long westbound detour was costly and required traffic control devices throughout (Wimmer 2004). Furthermore, traffic crossing the Arkansas River was suspended for a period during the I-40 Webbers Falls Bridge restoration. Motivations such as great economic loss should be considered in emergency situations such as the collapse of the I-40 Webbers Falls Bridge. Clear and immediate communication with truck traffic, and when feasible, convenient detours with traffic control devices and operators should be put in effect to limit disruption to commerce (Georgia Tech Research Corporation et al. 2012).

17 5C.14 Mathews Bridge 2013 [Collision]Table C-14. Mathews Bridge Collision Case Study Name/ Date Mathews Bridge Collision (2013)L ocation Florida, USAEvent Type CollisionBridge Name Mathews BridgeBridge Type Steel cantilever through truss; total length: 7 ,37 6 ft; main span: 8 10 ftScope/ Costs Severed main tension chord; closing the bridge for 33 days; total cost of $ 1.07 millionPlanning Techniques/ Tools N/ AEvent Response Immediate closure of bridge, collaboration of engineers, designers, inspectors, fabricators, and emergency respondersAssessment Techniques/ Tools Photos, visual inspection, and strain gaugesRapid Restoration Type Temporary chord placement, followed by permanent built-up steel member chord Innovations • Temporary chord placement with jacks• L aser scanning gusset plate for quicker and more accuratecomponent manufacturing• Pully system to hoist up components from barges belowC.14.1 IntroductionO n S e p t e m b e r 2 6 t h , 2 0 1 3 , a U S N a v a l S h i p c o l l i d e dw i t h t h e M a t h e w s B r i d g e , s t r i k i n g t h e n o r t h b o t t o mt r u s s c h o r d a b o u t h a l f w a y a l o n g t h e m i d d l e s p a n . T h es t e r n o f t h e s h i p w a s a l r e a d y u n d e r n e a t h t h es u p e r s t r u c t u r e , b u t t h e s t e r n r a m p w a s n o t l o w e r e d ,a n d i t s t r u c k t h e b r i d g e . T h e s h i p ’ s m o m e n t u m w a s t o og r e a t t o s t o p b e f o r e t h e d a m a g e c o u l d e n s u e .S u b s e q u e n t i n s p e c t i o n s f o u n d t h e i m p a c t l e f t t h et e n s i o n c h o r d ( t h e b o t t o m m e m b e r o f t h e t r u s s ) c u t ,w h i c h f o r c e d a l o a d r e d i s t r i b u t i o n , a n d t h e f l o o rs y s t e m t o o k o n t h e “ e x t r a ” l o a d , a s s h o w n i n F i g u r e C -5 4 . T h i s p u t e x t r a s t r e s s o n m e m b e r s t h a t w e r e n o to r i g i n a l l y d e s i g n e d t o r e s i s t . A n y a d d i t i o n a l l o a d s f r o m t r a f f i c w o u l d h a v e p u t t h e b r i d g e a t r i s k f o r c o l l a p s e .T h e s e v e r e d t r u s s e l e m e n t w a s f r a c t u r e c r i t i c a l d u e t o i t s c l a s s i f i c a t i o n a s a t e n s i l e c a r r y i n g , n o n r e d u n d a n tm e m b e r . T h e b r i d g e r e o p e n e d t o t r a f f i c t h i r t y - t h r e e d a y s a f t e r t h e i m p a c t , s a v i n g r o a d u s e r s a n e s t i m a t e d$ 7 m i l l i o n d u e t o i t s r a p i d c o m p l e t i o n ( W a t t s 2 0 1 3 ) .C.14.1.1 Event ResponseT h e b r i d g e w a s c l o s e d i m m e d i a t e l y a f t e r t h e c o l l i s i o n , a n d a l l r i v e r t r a f f i c w a s s u s p e n d e d . W h i l e t h es h u t d o w n w a s t a k i n g p l a c e , t h e F l o r i d a D O T i n s p e c t e d t h e b r i d g e a n d f o u n d t h e d a m a g e t o b e s e v e r eFigure C-54. Severed Tension Chord (Courtesy of Sanya Watts, Watts 2013)

17 6( A l i p o u r 2 0 1 6 ) . T h e J a c k s o n v i l l e S h e r i f f ’ s O f f i c e c o o r d i n a t e d t h e b r i d g e c l o s u r e , a n d t h e U S C o a s t G u a r d( U S C G ) t a c k l e d t h e r i v e r s h u t d o w n . T h e U S C G a l s o p r o t e c t e d t h e e q u i p m e n t d u r i n g t h e r e p a i r a s n e e d e d .I n s p e c t i o n c r e w s a r r i v e d o n s c e n e w i t h i n f o u r h o u r s o f t h e i m p a c t ( W a t t s 2 0 1 3 ) . T h e y s e n t a D e c l a r a t i o no f E m e r g e n c y l e t t e r t o t h e F l o r i d a S e c r e t a r y o f T r a n s p o r t a t i o n . T h i s d e c i s i o n a l l o w e d t h e F l o r i d a D O T t op r o c e e d w i t h r e p a i r s w i t h o u t a b i d i n g b y t r a d i t i o n a l a d v e r t i s i n g p r o t o c o l s f o r c o n t r a c t i n g ( A l i p o u r 2 0 1 6 ) .T o d e t e r m i n e t h e b e s t c o u r s e o f a c t i o n , t h e F l o r i d a D O T c r e a t e d a n e m e r g e n c y r e s p o n s e t e a m , w h i c hc o n s i s t e d o f b r i d g e e n g i n e e r s , s u r v e y o r s , c o n t r a c t o r s , f a b r i c a t o r s , a n d i n s p e c t o r s . T o g e t h e r , t h e t e a mg e n e r a t e d a b i d p a c k a g e w i t h i n s e v e n t y - s i x h o u r s o f t h e c o l l i s i o n , w o r k i n g t h r o u g h t h e n i g h t s t o c o m p l e t et h e p a c k a g e a t r e c o r d s p e e d . A n i n c e n t i v e / d i s i n c e n t i v e c l a u s e f o r $ 5 0 , 0 0 0 p e r d a y w a s i n c l u d e d , a n d t h es c h e d u l e s e t f o r f o r t y d a y s ( A l i p o u r 2 0 1 6 ) .O n g o i n g c o n s t r u c t i o n p r o j e c t s i n t h e s u r r o u n d i n g a r e a s w e r e s u s p e n d e d t o p r o v i d e a l t e r n a t i v e r o u t e s f o rc o m m u t e r s a n d t r a v e l e r s . I n s o m e c a s e s , c r e w s f r o m t h e s e j o b s i t e s w e r e r e a s s i g n e d t o w o r k o n t h e M a t h e w sB r i d g e r e p a i r .C.14.2 Emergency PlanningC.14.2.1 Crowdsourcing and Information GatheringT h e a c c i d e n t o c c u r r e d a r o u n d 2 p m o n S e p t e m b e r 2 6 t h , 2 0 1 3 . W i t n e s s e s c a p t u r e d a c e l l p h o n e v i d e o t h a tw a s l a t e r u s e d d u r i n g t h e a n a l y s i s .T o k e e p t h e p u b l i c i n t h e l o o p , d a i l y a n n o u n c e m e n t s w e r e m a d e t h r o u g h t h e F l o r i d a P u b l i c I n f o r m a t i o nO f f i c e a n d d i s t r i b u t e d t o c i t i z e n s t h r o u g h v a r i o u s f o r m s o f m e d i a . T h e F l o r i d a D O T w a n t e d t o n o t o n l yr e p a i r t h e b r i d g e a s q u i c k l y a s p o s s i b l e , b u t a l s o t o t e a c h t h e g e n e r a l p u b l i c t h e r e a s o n i n g b e h i n d t h e r e p a i rm e t h o d s . T h e F l o r i d a D O T a d d r e s s e d c o n c e r n s f r o m t h e p u b l i c a n d e m p h a s i z e d t h e i m p o r t a n c e o f s a f e t y .T o n o t i f y m o t o r i s t s a b o u t t h e c l o s u r e , a n I n t e l l i g e n t T r a n s p o r t a t i o n S y s t e m ( I T S ) w a s u s e d t o p r o v i d ei n f o r m a t i o n o n a l t e r n a t i v e r o u t e s a n d d e t o u r s . P o s t s o n s o c i a l m e d i a h i g h l i g h t e d k e y p r o g r e s s , a n d o n - s i t ep r e s s c o n f e r e n c e s w e r e h e l d r e g u l a r l y ( W a t t s 2 0 1 3 ) .C.14.3 AssessmentA f t e r t h e c o l l i s i o n , i n i t i a l i n s p e c t i o n s d u r i n g t h ee v e n i n g c o n s i s t e d o f t a k i n g p h o t o g r a p h s a n dd o c u m e n t i n g t h e d a m a g e s t o d e t e r m i n e g l o b a l s t a b i l i t ya n d t h e b e s t d e s i g n o p t i o n s .T h e n e x t d a y , c l i m b i n g i n s p e c t o r s a r r i v e d o n s c e n e t os c o u r t h e b r i d g e f o r m o r e d e t a i l e d v i e w s a t a r e a s o fc o n c e r n . U s i n g p h o t o s c o l l e c t e d f r o m t h e s c e n e a n dc o m p u t e r s o f t w a r e , F l o r i d a D O T b r i d g e d e s i g n e r sw o r k e d t o g e t h e r t o b r a i n s t o r m t h e b e s t w a y t o r e p a i r t h eb r i d g e . M e a n w h i l e , a t e a m w a s o r g a n i z e d t o g e n e r a t ec o r r e s p o n d i n g C A D f i l e s , a n d a n o t h e r t o d e v e l o p t h ec o n t r a c t s ( W a t t s 2 0 1 3 ) .T h e s t r u c t u r a l i n t e g r i t y o f t h e b r i d g e w a s o r i g i n a l l yu n k n o w n . I t w a s c o n c l u d e d t h a t t h e s e v e r e d c h o r dn e e d e d t o b e p u l l e d b a c k t o g e t h e r t o r e c o n n e c t t h e l o a dp a t h , w h i c h w o u l d a l s o r e m o v e t h e a d d i t i o n a l s t r e s s e so n o t h e r e l e m e n t s .T o m o n i t o r t h e e f f e c t s o f l o a d r e d i s t r i b u t i o n d u r i n g t h e r e p a i r , b o n d a b l e f o i l s t r a i n g a u g e s w e r e i n s t a l l e do n t h e d a m a g e d n o r t h t r u s s t o m o n i t o r t h e i n i t i a l a n d r e d i s t r i b u t i o n l o a d s o n t h e b r i d g e o n c e c o n s t r u c t i o nFigure C-55. Strain Gauge Installation and Wire Management (Courtesy of Sanya Watts, Watts 2013)

17 7b e g a n , a s s h o w n i n F i g u r e C - 5 5 ( A l i p o u r 2 0 1 6 a n d W a t t s 2 0 1 3 ) . T h i s w a s e s p e c i a l l y i m p o r t a n t d u r i n g t h ej a c k i n g a n d d e - t e n s i o n i n g p r o c e s s e s o f t h e c h o r d . T h e g a u g e s w e r e a l s o u s e d t o m o n i t o r f o r b u c k l i n g i n t h eu p p e r c h o r d d u r i n g r e p a i r , a n d o n t h e s o u t h t r u s s t o h a v e a p r e l i m i n a r y b a s i s t o c o m p a r e t h e d a t a f r o m t h en o r t h t r u s s ( A l i p o u r 2 0 1 6 ) .C.14.4 Rapid RestorationC.14.4.1 ContractingT h e b i d w a s a w a r d e d t w o d a y s a f t e r t h e p r e - b i d m e e t i n g , a n d t h e p r e - c o n s t r u c t i o n m e e t i n g w a s h e l d af e w h o u r s l a t e r . C r e w s w o r k e d 2 4 / 7 t o c o m p l e t e t h e p r o j e c t ( W a t t s 2 0 1 3 ) .C.14.4.2 Temporary StructureA t e m p o r a r y r e p a i r w a s p u t i n p l a c e t o p e r m i tc o n s t r u c t i o n o f t h e d a m a g e d c r o s s m e m b e r s , t h e n a f i n a lc h o r d r e p l a c e m e n t w a s d e s i g n e d , a n d t r a f f i c w a sr e t u r n e d ( A l i p o u r 2 0 1 6 ) . S u r v e y i n g w a s c o m p l e t e de a c h d a y t o m o n i t o r t h e d e c k a n d f l o o r b e a m s f o r a n ys i g n s o f c r e e p ( A l i p o u r 2 0 1 6 ) . A t e a c h c o m p l e t i o n o ft h e r e p a i r w o r k ( t e m p o r a r y a n d f i n a l ) , l o a d t e s t s w e r ec o n d u c t e d u s i n g F l o r i d a D O T f l a t b e d t r u c k s d r i v e na c r o s s t h e d e c k . T h e t r u c k s s t o p p e d a t t h r e e l o c a t i o n sa n d t h e b r i d g e w a s m o n i t o r e d f o r p e r f o r m a n c e , a ss h o w n i n F i g u r e C - 5 6 ( A l i p o u r 2 0 1 6 ) .C.14.4.3 Permanent StructureT h e f i r s t s t e p i n t h e r e p a i r p r o c e s s w a s t o i n s t a l l t h es c a f f o l d i n g t h a t w o u l d b e u s e d b y w o r k e r s , a s s h o w n i nF i g u r e C - 5 7 . T h i s w a s c h a l l e n g i n g d u e t o l o a dc o n s t r a i n t s o n t h e b r i d g e , s o t h e e n t i r e b r i d g e r e p a i r w a sc o m p l e t e d i n s t a g e s . O n c e t h e s c a f f o l d i n g w a s i n p l a c e ,a p a i r o f b e a m s w e r e p o s i t i o n e d s o t h e y c o u l d b ea n c h o r e d t o t h e e a s t e r n s p a n t o p r o v i d e s o m e g e o m e t r i cr e s t o r a t i o n t o t h e n o r t h t r u s s , a c t i n g l i k e a s t r o n g b a c ka n d s a d d l e s y s t e m . A p l a n t i n T a m p a , F L m a n u f a c t u r e ds e v e n t y - f o o t l o n g b e a m s a n d t h e n t r u c k e d t h e b e a m s t ot h e b r i d g e s i t e . B e c a u s e o f t h e l e n g t h o f t h e b e a m s i nt r a n s p o r t a t i o n , s p e c i a l p e r m i t s h a d t o b e a t t a i n e d , a n d ac a b l e p u l l y s y s t e m w a s u s e d t o s e t t h e m i n t o p l a c e .W i t h s u p p o r t f r o m t h e s t r o n g b a c k s , t h e d a m a g e d c o r dw a s c u t a n d r e m o v e d . T h e t h r e e - f o o t c h u n k s w e r e l i f t e dt o t h e d e c k a n d s a v e d f o r f u r t h e r i n s p e c t i o n , a s s h o w ni n F i g u r e C - 5 8 . F r o m h e r e , t h e t e m p o r a r y l o w e r c h o r dc o u l d b e i n s t a l l e d , w h i c h c o n s i s t e d o f f o u r s i x t y - s i x -f o o t t h r e a d e d r o d s . F o r t r e s s a n c h o r s w e r e b o l t e d t o t h el o w e r c h o r d w i t h o n e h u n d r e d h i g h s t r e n g t h b o l t s . O n c eFigure C-56. Load Testing (Courtesy of Sanya Watts, Watts 2013) Figure C-57. Scaffolding on Mathews Bridge (Courtesy of Sanya Watts, Watts 2013) Figure C-58. Hoisting up Damaged Chord Components (Courtesy of Sanya Watts, Watts 2013)

17 8i n p l a c e , j a c k s w e r e u s e d t o t e n s i o n t h e t e m p o r a r yc h o r d . T h i s w a s c o m p l e t e d i n c r e m e n t a l l y o v e r t h ec o u r s e o f f i v e d a y s . I n i t i a l l y , t h e g a p i n t h e c h o r d w a sn o t c l o s i n g , a n d t h i s w a s l a t e r f o u n d t o b e c a u s e d b yr e l a x i n g o f t h e b a r s . A “ j a c k t h e n r e l a x ” s y s t e m w a su s e d t o g r a d u a l l y t o c l o s e t h e g a p ( W a t t s 2 0 1 3 ) .W i t h t h e t e m p o r a r y c h o r d i n p l a c e , o t h e r r e p a i r sc o u l d t h e n t a k e p l a c e o n t h e d a m a g e d c o m p o n e n t s , a ss h o w n i n F i g u r e C - 5 9 . T h e n o r t h b r a c i n g f a i l e d d u e t ob l o c k s h e a r a t a g u s s e t p l a t e a n d b u c k l i n g o c c u r r e d i nm a n y m e m b e r s . T h e f l o o r b e a m s t h a t w e r e m i s a l i g n e dd i d s t r a i g h t e n b a c k o u t w i t h t h e r e a l i g n e d g e o m e t r y o ft h e t e m p o r a r y c h o r d , b u t t h e d a m a g e d g u s s e t p l a t e s w e r e n o t r e a l i g n e d a n d s t i f f e n e d w i t h a n g l e s ( W a t t s2 0 1 3 ) .T o p r e p a r e f o r t h e p e r m a n e n t c h o r d m e m b e r , t h e a d j a c e n t g u s s e t p l a t e s n e e d e d t o b e h e a t - s t r a i g h t e n e d .H e a t w a s o n l y a p p l i e d o n e m i n u t e a t a t i m e w i t h a t o r c h , a n d t h e n t h e p l a t e s w e r e s l o w l y b e n t b a c k i n t os h a p e . T h i s t o o k a b o u t o n e h u n d r e d m a n - h o u r s t o c o m p l e t e . F r o m h e r e , a s t u b b e a m w a s i n s t a l l e d t o a l l o wf o r e a s i e r i n s t a l l a t i o n o f t h e p e r m a n e n t c h o r d b y s p l i c i n g t h e n e w m e m b e r t o t h i s s t u b b e a m i n s t e a d o f t h ep a n e l p o i n t ( W a t t s 2 0 1 3 ) .O n d a y t w e n t y - t w o o f t h e r e p a i r , t h e c r e w b e g a n s p l i c i n g t h e n e w c h o r d i n t o p l a c e . T h e n e w c h o r d w a sa b u i l t - u p s e c t i o n t h a t w a s d i s m a n t l e d o n c e i t r e a c h e d t h e s i t e a n d t h e n r e a s s e m b l e d i n p l a c e a n d b o l t e d i n t oi t s f i n a l p o s i t i o n . T h e b e a m w e i g h e d e i g h t k i p s , m a k i n g i t t o o h e a v y t o b e l i f t e d i n t o p l a c e , a n d t o od a n g e r o u s t o h o i s t f o r t y f e e t o f f t h e s i d e o f t h e b r i d g e w h i l e w e a v i n g t h r o u g h t h e t r u s s . A “ d o u b l e - b o l t a n dc h e e s e f i l l e r p l a t e m e t h o d ” w a s u s e d t o s t r e n g t h e n t h e g u s s e t p l a t e d a m a g e d d u r i n g t h e i m p a c t . T h i s c o u l db e d o n e w i t h o u t u n z i p p i n g t h e r i v e t s o f t h e e n t i r e c o n n e c t i o n a s t h e “ c h e e s e ” p l a t e w a s c u t t o f i t a r o u n d t h eb o l t s ( W a t t s 2 0 1 3 ) .A f t e r t h e n e w c h o r d w a s s e t i n p l a c e , t h e t e m p o r a r y c h o r d w a s d e - t e n s i o n e d , a n d t h e s c a f f o l d i n g r e m o v e d .T h e p r o j e c t w a s t h e n c o m p l e t e ( W a t t s 2 0 1 3 ) .C.14.5 ChallengesM o n i t o r i n g t h e f o r c e p a t h s a n d r e d i s t r i b u t i o n i si n s t r u m e n t a l d u r i n g t h e r e p a i r a n d e v a l u a t i n g t h ei n t e g r i t y / s a f e t y o f t h e r e p a i r e d b r i d g e . T o s t r e a m l i n e t h es t r a i n g a u g e i n s t a l l a t i o n p r o c e s s , t h e l o c a t i o n s w e r e p r e -m a p p e d o u t . T h e s e r e g i o n s w e r e t h e n c l e a n e d a n dp r e p p e d f o r p l a c e m e n t , i n c l u d i n g s u r f a c e f i n i s h i n g a n dw a t e r p r o o f i n g . T h e g a u g e s t h e m s e l v e s w e r e d e l i c a t ea n d w e l d e d i n - p l a c e . O v e r t h i r t e e n m i l e s o f w i r e w a sr u n a c r o s s t h e b r i d g e , l i n k i n g a l l t h e g a u g e s t o a c e n t r a ld a t a a c q u i s i t i o n s y s t e m ( D A Q ) . I n f o r m a t i o n i n t h eD A Q c o u l d b e a c c e s s e d f r o m a n y w h e r e , a l l o w i n g f o rr e a l - t i m e m o n i t o r i n g f r o m a n y l o c a t i o n , a s s h o w n i nF i g u r e C - 6 0 . D e l i c a t e c o o r d i n a t i o n h a d t o t a k e p l a c e n o t t o d a m a g e t h e g a u g e s o r t h e i r w i r e s t h r o u g h o u tt h e r e p a i r s .A m a j o r c h a l l e n g e f o r t h e p r o j e c t w a s t h e w e i g h t r e s t r i c t i o n o n t h e b r i d g e d u e t o t h e r e d i s t r i b u t i o n o f t h el o a d f r o m t h e s e v e r e d c h o r d m e m b e r . C r a n e s a n d o t h e r h e a v y e q u i p m e n t c o u l d n o t b e b r o u g h t o n t h e b r i d g e ,s o c r e w s h a d t o a s s e m b l e s o m e i t e m s i n p l a c e ( l i k e t h e p e r m a n e n t c h o r d ) o r u s e a p u l l y s y s t e m , a s s h o w ni n F i g u r e C - 6 1 .Figure C-59. Damaged Gusset Plate (Courtesy of Sanya Watts, Watts 2013) Figure C-60. Data Monitoring (Courtesy of Sanya Watts, Watts 2013)

17 9F o r t h e “ d o u b l e - b o l t a n d c h e e s e f i l l e r p l a t e ” a c h a l l e n g e a r o s e w i t h m e e t i n g t h e p r e c i s i o n n e e d e d t o c u tt h e “ c h e e s e p l a t e ” b o l t h o l e s . T h e s o l u t i o n c a m e f r o m u s i n g t h e s u r v e y i n g e q u i p m e n t a l r e a d y o n s i t e . Al a s e r s c a n n e r w a s u s e d t o m a p o u t t h e e x i s t i n g g u s s e t p l a t e w i t h a n a c c u r a c y o f 0 . 5 m m . T h e m a i n t e n a n c ec r e w s e v e n b u l t a b r a c k e t t o h o l d t h e l a s e r s c a n n e r o f ft h e s i d e o f t h e b r i d g e t o g e t t h e b e s t a n g l e f o r t h e s c a n .T h e r e s u l t s w e r e t h e n i m p o r t e d i n t o C A D f o r t h ef a b r i c a t o r t o m a n u f a c t u r e .C.14.6 Innovations and Lessons LearnedC.14.6.1 Laser Scanning for Accurate and PreciseMeasurementsT o p u l l o f f s u c h a m o n u m e n t a l t a s k , q u i c k a n de f f i c i e n t c o o r d i n a t i o n b e t w e e n i n s p e c t o r s , d e s i g n e r s ,c o n t r a c t o r s , a n d f a b r i c a t o r s h a d t o t a k e p l a c e . S o l u t i o n ss u c h a s u s i n g t h e l a s e r s c a n n e r t o d e v e l o p C A D f i l e s f o rt h e “ c h e e s e p l a t e ” o r t h e p e r f e c t f i t o f t h e b u i l t - u p n e w c h o r d w h i l e a s s e m b l e d i n p l a c e w o u l d n o t h a v e b e e nf e a s i b l e i f t h e r e w a s n o t c l e a r c o m m u n i c a t i o n .C.14.6.2 Declaration LetterT h e D e c l a r a t i o n o f E m e r g e n c y s e n t t o t h e F l o r i d a S e c r e t a r y o f T r a n s p o r t a t i o n p a v e d t h e w a y f o r e a s i e rp r o j e c t c o n t r a c t i n g a n d s p e d u p t h e e n t i r e r e p a i r p r o c e s s .C.14.6.3 Weight Restriction Pully SystemT h e r e d u c t i o n o f l o a d c a p a c i t y o n t h e b r i d g e d u r i n g r e p a i r s h a d a m a j o r i m p a c t . T h e d e c i s i o n t o u s e ap u l l y s y s t e m t o h o i s t u p c o m p o n e n t s f r o m t h e r i v e r b e l o w w a s a c r e a t i v e s o l u t i o n t o a v o i d t h e u s e o f h e a v yc r a n e s o r m a c h i n e s o n t h e b r i d g e d e c k .C.14.6.4 Structural MonitoringM a i n t a i n i n g c o n s i s t e n t s t r u c t u r a l m o n i t o r i n g d u r i n g t h e a s s e s s m e n t a n d r e p a i r o f t h e s t r u c t u r e e n s u r ew o r k e r s a f e t y , b u t a l s o v e r i f y t h e r e p a i r s w e r e w o r k i n g .Figure C-61. Repairs made next to Temporary Chord (Courtesy of Sanya Watts, Watts 2013)

18 0C.15 San Jacinto River I-10 2019 [Collision]Table C-15. San Jacinto River I-10 Bridge Case Study Name/ Date San Jacinto River I-10 Bridge (2019)L ocation Texas, USAEvent Type CollisionBridge Name I-10 San Jacinto River BridgeScope/ Costs Severe damage to several columns, total cost $ 3 millionPlanning Techniques/ Tools N/ AEvent Response Multi-jurisdictional Unified Command, detour routesAssessment Techniques/ Tools Underwater sonar images showing underwater damage, Diver observation, Expert on-site assessment, V ideosRapid Restoration Type Dolphin structures, Fender SystemInnovations • Drone-Based Data Collection• Bridge collision avoidance measuresC.15.1 IntroductionD u e t o t h e r e m n a n t s o f T r o p i c a l S t o r m I m e l d a , w h i c hc a u s e t h e s t r o n g c u r r e n t i n S a n J a c i n t o R i v e r , n i n e b a r g e sh a d b r o k e n a w a y f r o m t h e i r m o o r i n g s a t t h e S a n J a c i n t oR i v e r F l e e t o n S e p t e m b e r 2 0 t h , 2 0 1 9 . T w o o f t h e m h i t t h eI - 1 0 B r i d g e , c a u s i n g e x t e n s i v e d a m a g e t o t h e b r i d g e ' sc o n c r e t e c o l u m n s , a s s h o w n i n F i g u r e C - 6 2 . T h e I - 1 0B r i d g e w a s i m m e d i a t e l y c l o s e d , a n d c r e w s i m p l e m e n t e da l e n g t h y d e t o u r r o u t e . A f t e r t h e b a r g e s w e r e r e m o v e d ,T x D O T r e c o n f i g u r e d e a s t b o u n d a n d w e s t b o u n d t r a f f i c ,w i t h t w o l a n e s i n e a c h d i r e c t i o n , o n t h e e a s t b o u n d s i d e o ft h e b r i d g e u n t i l p e r m a n e n t r e p a i r s c o u l d b e m a d e ( B e g l e y2 0 1 9 ; T h e M a r i t i m e E x e c u t i v e 2 0 1 9 ) .C.15.1.1 Event ResponseI m m e d i a t e l y f o l l o w i n g t h e c o l l i s i o n , a U n i f i e d C o m m a n d w a s e s t a b l i s h e d . T h i s c o m m a n d w a s m a d e u po f t h e U . S . C o a s t G u a r d , t h e T e x a s D O T , t h e B a r g e C o m p a n y , a n d t h e T e x a s G e n e r a l L a n d O f f i c e ( C o a s tG u a r d N e w s 2 0 1 9 )A d d i t i o n a l l y , d e t o u r s w e r e e s t a b l i s e d . T o h e l p r e d u c e c o n g e s t i o n a n d t h e i n c o n v e n i e n c e t o d r i v e r s , t h eT e x a s D e p a r t m e n t o f T r a n s p o r t a t i o n ( T x D O T ) w a i v e d t h e t o l l s o n t h e S a m H o u s t o n T o l l w a y B r i d g e , w h i c hw a s l o c a t e d a l o n g t h e m a i n d e t o u r ( D e l o n y & C a r t e r 2 0 1 9 ) . T h e r e c o m m e n d e d r o u t e e x t e n d e d m o t o r i s t s ’c o m m u t e b y 2 0 m i l e s e a c h w a y u n t i l t h e w e s t b o u n d l a n e s w e r e c l e a r e d a s s a f e f o r t r a f f i c l o a d s . T h e n , t h e yw e r e r e c o n f i g u r e d t o t w o 1 1 ’ w i d e l a n e s i n e a c h d i r e c t i o n u n t i l r e p a i r s w e r e f i n a l i z e d ( B e g l e y 2 0 1 9 ) .Figure C-62. Severe Column Damage from Barge Impact (Clement 2019)

18 1C.15.2 Emergency PlanningC.15.2.1 Crowdsourcing and Information GatheringT h e U . S . C o a s t G u a r d S e c t o r H o u s t o n - G a l v e s t o n r e c e i v e d a r e p o r t a t a b o u t 1 2 : 0 5 a m . t h a t s e v e r a l b a r g e sh a d f l o a t i n g a w a y f r o m t h e i r m o o r i n g . T h e C o a s t G u a r d d i s p a t c h e d a h e l i c o p t e r a n d r e s p o n s e b o a t , w h oc o n f i r m e d t h a t t w o b a r g e s h a d s t r u c k t h e I - 1 0 b r i d g e , c a u s i n g v i s i b l e c o l u m n d a m a g e . A r o u n d 4 a m , T x D O Tc l o s e d a l l l a n e s o f t h e I - 1 0 B r i d g e . A f t e r t h e i n i t i a l r e p o r t s , d r o n e f o o t a g e w a s c a p t u r e d a n d r e l e a s e d a s p a r to f t h e i n v e s t i g a t i o n ( C l e m e n t 2 0 1 9 ) .C.15.3 AssessmentT h e d r o n e f o o t a g e w a s f i r s t u s e d t o a s s e s s t h e i n i t i a l d a m a g e . L i m i t e d a c c e s s a n d h i g h f l o o d w a t e r s m a d ec o n t a c t d i f f i c u l t , s o t h e f o o t a g e w a s v i t a l f o r i n i t i a l i n s p e c t i o n s ( C l e m e n t 2 0 1 9 ) .T h e M o n d a y f o l l o w i n g t h e e v e n t , p r o f e s s i o n a l d i v e r s a n d s t a t e e n g i n e e r t e a m s i n s p e c t e d t h e b r i d g e ,c o n f i r m i n g d a m a g e t o s e v e r a l s u p p o r t c o l u m n s o n t h e w e s t b o u n d s p a n o f t h e d o u b l e b r i d g e . I n i t i a ls p e c u l a t i o n f r o m T x D O T i n c l u d e d l a r g e s e c t i o n s o f d a m a g e , r e q u i r i n g t h e n e e d o f a f u l l c o l u m nr e p l a c e m e n t ( B e g l e y 2 0 1 9 ) .T h e s e a s s e s s m e n t s a l s o c o n f i r m e d t h a t t h e e a s t b o u n d b r i d g e w a s u n a f f e c t e d b y t h e b a r g e h i t s . T h u s ,T x D O T f e l t c o n f i d e n t e n o u g h t o r e o p e n t h e e a s t b o u n d l a n e s t o t r a f f i c . C.15.4 Rapid RestorationC.15.4.1 ContractingA c o n t r a c t o r w a s h i r e d f o r t h e p r o j e c t i n m i d - O c t o b e r ,a n d c o n s t r u c t i o n c o m m e n c e d n e a r t h e e n d o f t h e m o n t h .T h e c o n t r a c t w a s e s t i m a t e d a t $ 3 m i l l i o n a n d w a ss c h e d u l e d f o r c o m p l e t i o n i n F e b r u a r y o f 2 0 2 0( H e r n a n d e z 2 0 1 9 ) . M o s t o f t h e r e p a i r s f o c u s e d o ns t r e n g t h e n i n g a n d s t a b i l i z i n g t h e d a m a g e d c o l u m n s .O n J a n u a r y 2 2 , 2 0 2 0 , t h e T e x a s D e p a r t m e n t o fT r a n s p o r t a t i o n a n n o u n c e d a l l m a i n l a n e s o f t h e I - 1 0F r e e w a y a t t h e S a n J a c i n t o R i v e r w e r e b a c k o p e n( A B C 1 3 2 0 2 0 ) .C.15.4.2 Permanent StructureT h e f i n a l r e p a i r s f o r t h e I - 1 0 b r i d g e i n c l u d e d t h e r e p l a c e m e n t o f t h e d a m a g e d d o l p h i n s t r u c t u r e s a n df e n d e r s y s t e m s . T h e s e w e r e c r u s h e d b y t h e b a r g e s a n d a r e t h e b r i d g e ’ s m a i n d e f e n s e a g a i n s t s i m i l a rc o l l i s i o n s . I n t o t a l , f o u r d o l p h i n s t r u c t u r e s w e r e r e p l a c e d , e a c h c a p a b l e o f w i t h s t a n d i n g 3 0 L F . T h ec o r r e s p o n d i n g f e n d e r s w e r e b u i l t w i t h 1 8 - i n c h d i a m e t e r s t e e l t h a t w a s c o a t e d w i t h m a r i n e - g r a d e e p o x y . T h ef e n d e r s y s t e m c o n s i s t e d o f 7 7 s t e e l p i l i n g s i n t o t a l , a n d s e v e r a l w e r e c o v e r e d i n r i p r a p , a s s h o w n i n F i g u r eC - 6 3 ( S t a r c o u r i e r n e w s 2 0 2 0 )Figure C-63. Dolphin and Fender Repair (Courtesy of Highlands Star Crosby Courier Newspaper, Star Courier News 2020)

18 2C.15.5 ChallengesT h e c l o s u r e o f t h e I - 1 0 b r i d g e s s i g n i f i c a n t l y i m p a c t e d t r a v e l t i m e s i n t h e a r e a . T x D O T h a d t o c a r e f u l l yp l a n a d e t o u r r o u t e t h a t w o u l d h a n d l e t h e i n c r e a s e i n t r a f f i c l o a d s . T h e w a i v e r o f t o l l s o n t h e S a m H o u s t o nB r i d g e h e l p e d r e d u c e t h e f r u s t r a t i o n f e l t b y m o t o r i s t s .F u r t h e r m o r e , t h e r e w e r e m a n y c o n c e r n s c e n t e r i n g a r o u n d t h e r e m o v a l o f t h e b a r g e s ( F i g u r e C - 6 4 ) . T h et w o b a r g e s w e r e c a r r y i n g t o x i c s u b s t a n c e s , a n d t h e r e w a s w o r r y t h e y h a d a l r e a d y , o r c o u l d c a u s e ,c o n t a m i n a t i o n i n t o t h e S a n J a c i n t o R i v e r . M o r e o v e r , d u r i n g r e p a i r s , b a r g e t r a f f i c w a s l i m i t e d t o p r e v e n tf u r t h e r d a m a g e . T h e I - 1 0 b r i d g e h a d b e e n s t r u c k m u l t i p l e t i m e s b e f o r e b y b a r r a g e s , s o i t w a s n o t a nu n c o m m o n e v e n t ( M c C o r m a c k 2 0 1 9 ) . A d d i t i o n a l l y , t h e S a n J a c i n t o W a s t e P i t s S u p e r f u n d S i t e i s l o c a t e da d j a c e n t t o t h e b r i d g e , s o t h e r e w a s c o n c e r n r e m o v i n g t h e b a r g e s m i g h t i m p a c t t h e s i t e . F o r t u n a t e l y , t h e U SC o a s t G u a r d c o n f i r m e d t h e r e w a s n o a d v e r s e i m p a c t t o t h e r i v e r , o r t h e S u p e r f u n d S i t e c a u s e d b y t h e b a r g ec o l l i s i o n ( B e g l e y 2 0 1 9 ) .C.15.6 Innovations and Lessons LearnedC.15.6.1 Special Considerations Needed for Problematic AreasT h e b r i d g e h a d e x p e r i e n c e f r e q u e n t c o l l i s i o n s w i t h b a r g e s . I n F e b r u a r y o f 2 0 1 9 , t h e b r i d g e w a s s t r u c k b ya b a r g e i n t h e e x a c t s a m e l o c a t i o n . T h e d a m a g e c a u s e d b y t h i s c o l l i s i o n t o o k a b o u t 3 m o n t h s t o r e p a i r( D e l o n y & C a r t e r 2 0 1 9 ) . D o l p h i n s , f e n d e r s , a n d o t h e r t y p e s o f p r o t e c t i v e b a r r i e r s s h o u l d b e i n s t a l l e d a n dr e g u l a r l y m a i n t a i n e d n e a r b r i d g e s t h a t e x p e r i e n c e f r e q u e n c y c o l l i s i o n s . T h i s r e d u c e s t h e l i k e l i h o o d o fd a m a g e t o t h e s t r u c t u r e , a n d p r e v e n t s m a j o r e c o n o m i c d i s r u p t i o n c a u s e d b y f u l l b r i d g e c l o s u r e s o r e v e np a r t i a l o p e n i n g s .C.15.6.2 Drone-Based Data CollectionI n t h i s i n s t a n c e , t h e d a m a g e t o t h e c o l u m n s c o u l d n o t b e i n v e s t i g a t e d w i t h o u t a s n o o p e r v e h i c l e . H o w e v e r ,d u e t o t h e u n k n o w n e x t e n t o f t h e d a m a g e , i t w a s t o o d a n g e r o u s f o r c r e w s t o l o a d u p t h e b r i d g e w i t h h e a v yv e h i c l e s . U s i n g D r o n e s o r o t h e r u n m a n n e d a e r i a l s y s t e m s ( U A S ) a r e a g r e a t a l t e r n a t i v e t o i n s p e c t i o nd i f f i c u l t t o r e a c h o r u n s a f e r e g i o n s o f s t r u c t u r e . T h e f a s t - m o v i n g f l o o d w a t e r s a l s o m a d e t h e s t r u c t u r ei n a c c e s s i b l e b y b o a t i m m e d i a t e l y f o l l o w i n g t h e c o l l i s i o n , s o t h e c a p t u r e d d r o n e f o o t a g e p r o v i d e t h eo p p o r t u n i t y f o r i n s p e c t o r s a n d e n g i n e e r s t o b e a b l e t o a s s e s s t h e s i t u a t i o n w i t h o u t p u t t i n g a n y p e r s o n n e l i nh a r m ’ s w a y . D r o n e - b a s e d d a t a c o l l e c t i o n p r o v i d e s a r a p i d m e a n s t o c o m p r e h e n d d a m a g e a n d p l a n f o r ar e p a i r s o l u t i o n ..Figure C-64. Barge Removal (McCormack 2019)

18 3C.16 Scottsburg Bridge 2017 [Collision]Table C-16. Scottsburg Bridge Case Study Name/ Date Scottsburg Bridge (2017 )L ocation Oregon, USAEvent Type CollisionBridge Name Scottsburg BridgeScope/ Costs $ 300,000, full bridge closurePlanning Techniques/ Tools Flash alerts from 911 calls to DOTEvent Response Full bridge closure, 100-mile detour routeAssessment Techniques/ Tools V isual assessment, laser scans, and MDT testingRapid Restoration Type Heat straightening and member strengtheningInnovations • Using L idar to look for minute deflection in members• Using scan data to generate finite element model for loadrating analysisC.16.1 IntroductionO n W e d n e s d a y , A p r i l 1 2 t h , 2 0 1 7 , a s e m i - t r u c k c r a s h e di n t o o n e o f t h e c o m p r e s s i o n m e m b e r s o n t h e h i s t o r i cS c o t t s b u r g B r i d g e a l o n g H i g h w a y 3 8 n e a r S c o t t s b u r g ,O r e g o n , a s s h o w n i n F i g u r e C - 6 5 . T h e t h r o u g h - t r u s s w a so r i g i n a l l y c o n s t r u c t e d i n 1 9 2 9 a n d h a d b e e n a r e p e a tv i c t i m o f c o l l i s i o n s . T h e n a r r o w , w i n d y r o a d l e a d i n g u pt o t h e b r i d g e c a u s e d i t t o b e f r e q u e n t l y h i t . T h i s t i m e ,h o w e v e r , t h e d a m a g e w a s s i g n i f i c a n t , a n d t h e b r i d g e w a sf u l l y c l o s e d f o r 4 d a y s , f o r c i n g d r i v e r s t o u s e a 1 0 0 + m i l ed e t o u r . L o c a l s c h o o l d i s t r i c t s a l s o w e r e f o r c e d t o u s e t h ed e t o u r , a d d i n g 1 . 5 + h o u r s t o s t u d e n t ’ s b u s r i d e s t o a n df r o m s c h o o l ( K P I C 2 0 1 7 b ) . T h e O r e g o n D O T h i r e d ac o n t r a c t o r t o p e r f o r m h e a t s t r a i g h t e n i n g o n t h e d a m a g e dm e m b e r a n d c a l l e d i n i t s g e o m e t r o n i c s g r o u p t o t a k el a s e r s c a n s o f t h e b r i d g e t o i d e n t i f y a n y o t h e r a r e a s o fh i d d e n d a m a g e ( K i n n e y 2 0 1 7 ) .C.16.1.1 Event ResponseC a l l s a b o u t t h e c o l l i s i o n w e r e f i r s t r e p o r t e d t o d i s p a t c h e r s . O r e g o n D O T m a i n t e n a n c e c r e w s w e r ed i s p a t c h e d s h o r t l y a f t e r . T h e b r i d g e w a s i m m e d i a t e l y c l o s e d f o l l o w i n g t h e c o l l i s i o n a n d s t a y e d c l o s e d f o r4 d a y s .Figure C-65. Truck on Truss Member (Oregon DOT 2017)

18 4C.16.2 Emergency PlanningT h e S c o t t s b u r g B r i d g e h a d b e e n h i t m u l t i p l e t i m e ss i n c e i t s o r i g i n a l c o n s t r u c t i o n i n 1 9 2 9 , a s s h o w n i nF i g u r e C - 6 6 . T h e c o m b i n a t i o n o f t h e a p p r o a c h r o a d w a ya n d n a r r o w s t r u c t u r e r o u t i n e l y l e f t a p i l e o f s i d e m i r r o r s ,a w n i n g s , a n d o t h e r c a r p a r t s i n t h e U m p q u a r i v e r b e l o w .O D O T h a s p l a c e d s e v e r a l “ n a r r o w b r i d g e ” s i g n s b e f o r ee a c h f i n a l a p p r o a c h t o t h e b r i d g e t o w a r n d r i v e r s . O n t h eo p p o s i t e s i d e o f t h e m a i n c o l l i s i o n , t h e y e v e n w r a p p e d at i m b e r b e a m t o t h e c o m p r e s s i o n m e m b e r t o p r o t e c t i tf r o m f u t u r e c r a s h e s . U n f o r t u n a t e l y , d u r i n g t h i s c o l l i s i o n ,t h a t w a s n o t t h e c r a s h l o c a t i o n .C.16.2.1 Crowdsourcing and Information GatheringT h e O r e g o n D O T u s e s a F l a s h A l e r t s y s t e m t h a ta u t o m a t i c a l l y n o t i f i e s t h e D O T w h e n t h e r e i s a c o l l i s i o n ,o r a 9 1 1 c a l l r e l a t e d t o a b r i d g e . T h i s w a s h o w t h e y w e r en o t i f i e d i n t h e c a s e o f t h i s c o l l i s i o n . T h e d i s t r i c tm a i n t e n a n c e s t a f f r e c e i v e t h e a l e r t f r o m t h e s y s t e m a n da r e t h e f i r s t o n s c e n e f r o m t h e D O T t o i n v e s t i g a t e . T h e n ,i f t h e i r i n i t i a l a s s e s s m e n t s w a r r a n t f u r t h e r e x p l o r a t i o n ,t h e y c a n c a l l i n f o r e n g i n e e r s t o c o m e o u t a n d p e r f o r mt h e i r a s s e s s m e n t . T h i s i s t h e p r o c e s s t h a t o c c u r r e d f o r t h eS c o t t s b u r g b r i d g e . F i g u r e C - 6 7 s h o w s s o m e o f t h ed a m a g e a f t e r t h e t r u c k w a s r e m o v e d f r o m t h e t r u s s .C.16.3 AssessmentA f t e r t h e w r e c k w a s r e m o v e d f r o m t h e b r i d g e , t h ef o c u s o f t h e i n s p e c t i o n w a s t h e d a m a g e d c o m p r e s s i o nm e m b e r . A v i s u a l i n s p e c t i o n i n d i c a t e d t h i s s t e e l t r u s se l e m e n t w a s s e v e r e l y d e f o r m e d , i n c l u d i n g a c h a n g e i ns e c t i o n t h i c k n e s s , d e f l e c t i o n , p a i n t d e l a m i n a t i o n , l o c a lf l a n g e b u c k l i n g , a n d h i g h s t r e s s p o i n t s , a s s h o w n i nF i g u r e C - 6 8 . M e a s u r e m e n t s w e r e t a k e n o f t h e d e f o r m e ds e c t i o n , a n d p a i n t w a s r e m o v e d t o b e t t e r v i e w t h e m e t a l .M T t e s t i n g w a s p e r f o r m e d o n s e v e r a l a r e a s t o s h o wc r a c k p r o p a g a t i o n , w h i c h w a s n e a r t h e w e b a n d f l a n g ei n t e r f a c e . C r a c k s n e a r s o m e o f t h e m e m b e r ’ s r i v e t s a n di n a n a n g l e p i e c e o f t h e n e a r b y f l o o r b e a m w e r e a l s on o t e d ( D o b s o n 2 0 1 7 ) .P r i o r t o t h e 2 0 1 7 c r a s h , t h e b r i d g e w a s p a r t o f a n O r e g o n D O T 3 D m o b i l e s c a n n i n g p r o j e c t , w h i c hg a t h e r e d 3 D p o i n t c l o u d d a t a . A f t e r t h e c r a s h , t h e r e w e r e s t i l l s i g n s o f d i s t r e s s a f t e r t h e v i s u a l i n s p e c t i o na n d M T t e s t i n g . O r e g o n D O T ’ s g e o m e t r o n i c s u n i t w a s c a l l e d t o s c a n t h e b r i d g e a g a i n t o h e l p s p o t t h er e g i o n s o f d a m a g e . T h e d a t a c o l l e c t e d w a s c o m p a r e d t o t h e p r e v i o u s s c a n s w h i c h i n d i c a t e d o n e o f t h e t r u s sl i n e s h a d d e f l e c t e d d o w n b y a p p r o x i m a t e l y 2 i n . T h e b r i d g e ’ s t r u s s f e a t u r e s a c o n t i n u o u s s p a n o v e r a l l t h ei n t e r m e d i a t e b e n t s , w h i c h c a u s e d c o n c e r n w i t h t h e 2 i n d e f l e c t i o n . T h i s m e a n t t h e s t r u c t u r e ’ s l o a d p a t h h a db e e n d i s r u p t e d a n d r e d i s t r i b u t e d t o m e m b e r s n o t d e s i g n e d t o c a r r y t h a t l o a d . A l o a d r a t i n g w a s t h e nFigure C-67. Side View of Member Distortion (Dobson 2017)Figure C-68. Compression Member Buckling (Dobson 2017)Figure C-66. Original Construction (Oregon DOT 1929)

18 5p e r f o r m e d o n t h e s t r u c t u r e a n d f o u n d t h a t t h e p r e v i o u s r a t i n g n e e d e d t o b e u p d a t e d , a s t h e i n t e r i o r b e n t sw e r e n o w c a r r y i n g s i g n i f i c a n t l y m o r e l o a d i n s o m e c a s e s ( K i n n e y 2 0 1 7 ) .C.16.4 Rapid RestorationC.16.4.1 ContractingT h e O r e g o n D O T h i r e d t w o c o n t r a c t o r s f o r t h e b r i d g e u s i n g e m e r g e n c y c o n t r a c t s . T h e f i r s t c o n t r a c t o rw a s r e s p o n s i b l e f o r t h e t e m p o r a r y r e p a i r s a n d t h e s e c o n d w a s f o r t h e p e r m a n e n t s o l u t i o n .C.16.4.2 Temporary StructureH e a t s t r a i g h t e n i n g w a s p e r f o r m e d o n t h e d a m a g e d m e m b e r . T h e c r e w s h a d t o c o m p l e t e m u l t i p l e c y c l e sf o r t h e s t e e l t r u s s t o s h i f t b a c k i n t o p l a c e . H o w e v e r , s i n c e t h e b r i d g e h a d b e e n h i t i n t h i s l o c a t i o n b e f o r e ,a n d h a d u n d e r g o n e h e a t s t r e n g t h e n i n g , i t w a s d e t e r m i n e d t h a t a m o r e p e r m a n e n t r e p a i r n e e d e d t o t a k e p l a c ef o r i n c r e a s e d s t r e n g t h .C.16.4.3 Permanent StructureF o r t h e p e r m a n e n t s t r e n g t h e n i n g r e p a i r , a d d i t i o n a l p l a t e s w e r ea d d e d t o t h e d a m a g e d e l e m e n t t o r e i n f o r c e t h e m e m b e r . T h i sr e p a i r w a s c o m p l e t e d 9 d a y s a f t e r t h e c o l l i s i o n , a n d t h e b r i d g e w a sa b l e t o f u l l y r e o p e n a f t e r t h i s s u c c e s s .C.16.5 ChallengesE v e n a f t e r t h e v i s u a l a s s e s s m e n t w a s c o m p l e t e , t h e e n g i n e e r sa n d i n s p e c t o r s o n s i t e w e r e p u z z l e d , a s w a t e r w a s p o o l i n g o n t h ed e c k n e a r w h e r e t h e d a m a g e d m e m b e r w a s l o c a t e d , e v e n a f t e r t h eh e a t s t r a i g h t e n i n g . T h i s i n d i c a t e d t h e r e w e r e a d d i t i o n a ld e f l e c t i o n s c a u s e d b y t h e a c c i d e n t , b u t c r e w s c o u l d n o t d e t e r m i n ew h e r e . A t t h i s p o i n t , t h e g e o m e t r o n i c s g r o u p w a s c a l l e d o n s c e n et o p e r f o r m t h e s c a n s a n d h e l p i d e n t i f y t h e a r e a s o f f u r t h e r d a m a g e( F i g u r e C - 6 9 ) ( K i n n e y 2 0 1 7 ) .T h e 1 0 0 + m i l e d e t o u r p u t a n a d d e d p r e s s u r e o n t h e p r o j e c t .M o r e o v e r , d o z e n s o f l o c a l c h i l d r e n w e r e u n a b l e t o g e t t o s c h o o l ,a n d b u s s e s h a d t o a d d a n e x t r a 1 . 5 h o u r s t o t h e i r r o u t e s e a c h d a yb e c a u s e o f t h e d e t o u r . C r e w s w o r k e d u p w a r d s o f 1 8 h o u r s a d a yt o c o m p l e t e t h e h e a t s t r e n g t h e n i n g r e p a i r o v e r t h e w e e k e n df o l l o w i n g t h e c o l l i s i o n . F u r t h e r m o r e , t h e l o c a l s c h o o l d i s t r i c t sa l s o w o r k e d o u t c o n t i n g e n c y p l a n s w i t h t h e O r e g o n D O T f o ra l t e r n a t i v e r o u t e s f o r t h e k i d s t o g e t t o s c h o o l s h o u l d t h e r e p a i rt a k e l o n g e r t h a n t h e w e e k e n d . L u c k i l y , o n e l a n e o f t r a f f i c w a s a b l et o o p e n t h e f o l l o w i n g S u n d a y ( K P I C 2 0 1 7 a ) . Figure C-69. Floorbeam Buckling (Dobson 2017)

186 C.16.6 Innovations and Lessons LearnedC.16.6.1 Lidar ScansHaving pre-collision lidar scan data of the bridge prior to the collision proved to be an asset. Thisprovided the baseline conditions that future scans could be compared to, and helped locate additional areas of damage that were undetectable with visual inspections alone. This data also made it easier to perform the load rating analysis, as the change in load path could easily be identified and current conditions of truss elements could be modeled with higher accuracy.

18 7C.17 Skagit River Bridge 2013 [Collision]Table C-17. Skagit RiverCase Study Name/ Date Collapse of I-5 Skagit River Bridge (2013)L ocation Washington, USAEvent Type CollisionBridge Name Skagit River Bridge Scope/ Costs All six lanes of a single span (Northbound and Southbound) of Interstate 5 collapsed, total cost about $ 18 millionPlanning Techniques/ Tools 911 calls to gather information Event Response Multi-jurisdictional, detour routes, and freight alerts to inform truck trafficAssessment Techniques/ Tools Photos, eyewitnesses, measurements, collapse video, and CAD drawingsRapid Restoration Type Temporary modular bridge; lateral bridge slide – ABC techniqueInnovations • Modular truss bridge as a temporary structure to reopeninterstate quickly while construction took place alongside• Reusing undamaged components customizing new spancharacteristics to match the existing bridge.C.17.1 IntroductionO n M a y 2 3 r d , 2 0 1 3 , a n o v e r h e i g h t t r u c kc r a s h e d i n t o t h e t o p p o r t a l o n S p a n 8 o f t h eS k a g i t R i v e r B r i d g e o n I n t e r s t a t e 5 , n e a r M t .V e r n o n , W a s h i n g t o n . T h i s c o l l i s i o n c a u s e d t h es p a n t o c o l l a p s e , f a l l i n g i n t o t h e S k a g i t R i v e r ,a l o n g w i t h s e v e r a l c a r s o n t h e b r i d g e , a s s h o w ni n F i g u r e C - 7 0 . ( N a t i o n a l T r a n s p o r t a t i o nS a f e t y B o a r d 2 0 1 4 ) . N o o n e w a s s e r i o u s l y h u r t ,b u t t h e b r i d g e d i d l e a v e I n t e r s t a t e 5 c l o s e d f o r2 7 d a y s u n t i l c r e w s c o u l d i n s t a l l a t e m p o r a r ys t r u c t u r e . U s i n g A c c e l e r a t e d B r i d g eC o n s t r u c t i o n ( A B C ) , a n e w s p a n w a s b u i l tp a r a l l e l t o t h e t e m p o r a r y b r i d g e . W h e n i t w a sn e a r l y a s s e m b l e d , t h e n e w s p a n w a s s l i d i n t op l a c e a n d f i n a l a s s e m b l y w a s c o m p l e t e d , o n l yf o u r m o n t h s a f t e r t h e i n c i d e n t . C r e w s a l s o r a i s e d t h e e l e v a t i o n o f t h e a r c h e d p o r t a l s o n t h e r e s t o f t h e b r i d g et o a h e i g h t o f 1 8 f e e t t o p r e v e n t f u t u r e c o l l i s i o n s . T h i s w a s a c c o m p l i s h e d b y p a r t i a l l y d i s m a n t l i n g t h e p o r t a l sa n d r e a s s e m b l i n g t h e m i n a d i f f e r e n t a r r a n g e m e n t ( W a s h i n g t o n S t a t e D O T 2 0 1 4 ) . T h e t e m p o r a r y s t r u c t u r ea n d s u b s e q u e n t r e p l a c e m e n t c o s t $ 1 8 m i l l i o n , a n d a l l b u t $ 1 m i l l i o n w a s f u n d e d b y t h e U S D O T ( A s s o c i a t e dP r e s s 2 0 1 3 ) . O v e r a l l , t h i s p r o j e c t s e r v e s a s a n e x c e l l e n t e x a m p l e o f r a p i d r e s t o r a t i o n , s t e m m i n g f r o m t h ee m e r g e n c y r e s p o n s e a n d i n s t a l l a t i o n o f a t e m p o r a r y s t r u c t u r e t o c o m p l e t i n g t h e n e w s p a n s a n d r e s t o r i n g t h ee n t i r e b r i d g e .Figure C-70. Collapse of Skagit River Bridge (Washington State DOT 2014)

18 8C.17.1.1 Event ResponseT r a f f i c e n g i n e e r s h a d t o r e - r o u t e I - 5 t r a f f i c t h r o u g h t h e c i t i e s o f M t . V e r n o n a n d B u r l i n g t o n t o d i v e r ti n t e r s t a t e t r a f f i c a r o u n d t h e c o l l a p s e d b r i d g e . A b o u t 7 1 , 0 0 0 v e h i c l e s w e r e i m p a c t e d d a i l y d u r i n g t h i s t i m e .A l e r t s w e r e c a s t o u t t o t r u c k t r a f f i c v i a F r e i g h t A l e r t s .C.17.2 Emergency PlanningA s s o o n a s t h e c o l l a p s e o c c u r r e d , t h e r e w a s a n i m m e d i a t e r e s p o n s e f r o m l a n d , a i r , a n d w a t e r . T h e S k a g i tC o u n t y S h e r i f f ’ s O f f i c e , M t . V e r n o n / B u r l i n g t o n P o l i c e a n d F i r e , a n d t h e W a s h i n g t o n D e p a r t m e n t o fT r a n s p o r t a t i o n ( W S D O T ) q u i c k l y r e s p o n d e d o n t h e g r o u n d . T h e n e a r b y W h i d b e y I s l a n d A i r S t a t i o n ( N a v y )s e n t a i r s u p p o r t , a n d t h e U S C o a s t g u a r d s e n t i n r e s c u e r s f r o m t h e r i v e r ( A l i p o u r 2 0 1 6 ) .C.17.2.1 Information GatheringS h o r t l y a f t e r t h e c o l l i s i o n a n d s u b s e q u e n t c o l l a p s e , t h e S k a g i t C o u n t y E m e r g e n c y C o m m u n i c a t i o n sC e n t e r r e c e i v e d 9 1 1 c a l l s . O p e r a t o r s w e r e t o l d t h e b r i d g e h a d c o l l a p s e d . T h i s i n f o r m a t i o n w a s v e r i f i e d b yt h e r e s p o n d e r s f i r s t o n s c e n e , a b o u t 3 m i n u t e s a f t e r t h e f i r s t 9 1 1 c a l l s ( N a t i o n a l T r a n s p o r t a t i o n S a f e t y B o a r d2 0 1 4 ) .C.17.3 AssessmentT h e N a t i o n a l T r a n s p o r t a t i o n S a f e t y B o a r d ( N T S B ) i n t e r v i e w e d s e v e r a l d r i v e r s w h o e i t h e r p a s s e d t h eo v e r h e i g h t v e h i c l e o r w h o w e r e o n t h e b r i d g e a t t h e s a m e t i m e . T h e s e c i t i z e n s p r o v i d e d e y e - w i t n e s st e s t i m o n y a n d i d e n t i f i e d w h e r e t h e s t r i k e o c c u r r e d . T h e s e c u r i t y c a m e r a o f a n e a r b y c a r d e a l e r s h i p c a p t u r e dt h e c o l l a p s e o n v i d e o , a n d t h i s v i d e o w a s u s e d t o i d e n t i f y t h e c a u s e o f t h e c o l l a p s e . P h o t o s a n d c o m p o n e n tm e a s u r e m e n t s w e r e a l s o u s e d t o d e t e r m i n e t h e f a i l u r e m e c h a n i s m ( N a t i o n a l T r a n s p o r t a t i o n S a f e t y B o a r d2 0 1 4 ) .C.17.4 Rapid RestorationC.17.4.1 ContractingP r i o r t o t h e c o l l i s i o n , W S D O T h a d a ne m e r g e n c y c o n t r a c t w i t h a l o c a l c o n s t r u c t i o nf i r m t o c o m p l e t e r e p a i r s o n a n a d h o c b a s i s . T og e t t h e p r o j e c t i m p l e m e n t e d r a p i d l y , a n A + BB i d d i n g P r o c e s s w a s i m p l e m e n t e d , a n di n c l u d e d t h e u s e o f i n c e n t i v e s f o r e a r l ym i l e s t o n e c o m p l e t i o n s . T h e y a l s o l e f t t h e e x a c tt y p e o f b r i d g e ( p r e s t r e s s e d v s . s t e e l ) u p t o t h ew i n n i n g f i r m . T h i s e n c o u r a g e d f a s t e rc o n s t r u c t i o n w h i l e s t i l l m a k i n g s u r e t h e p r o j e c tw a s c o m p l e t e d a t a r e a s o n a b l e p r i c e( W a s h i n g t o n S t a t e D O T 2 0 1 6 ) .C.17.4.2 Temporary StructureT h e t e m p o r a r y s t r u c t u r e u s e d w a s a s i d e - b y - s i d e d u a l l a n e m o d u l a r t r u s s A C R O W b r i d g e . T h i s s t r u c t u r eh a d t o m a i n t a i n t h e s a m e r i v e r h e i g h t c l e a r a n c e a s b e f o r e ( o r c o u l d b e h i g h e r ) a n d e n s u r e t h e i n s t a l l a t i o nFigure C-71. Temporary modular bridge (Washington State DOT 2014)

18 9w a s q u i c k t o r e d u c e t r a f f i c d i s r u p t i o n , a n d n o t i n c r e a s e s e i s m i c l o a d s o n t h e s t r u c t u r e i n c a s e o f a ne a r t h q u a k e ( W a s h i n g t o n S t a t e D O T 2 0 1 4 ) . T h i s s y s t e m i s s h o w n i n F i g u r e C - 7 1 . T h e t e m p o r a r y s t r u c t u r ew a s a s s e m b e l d a n d i n s t a l l e d b y t h e e m e r g e n c y c o n t r a c t o r a l r e a d y e s t a b l i s e h d b y W S D O T p r i o r t o t h ec o l l i s i o n .C.17.4.3 Permanent StructureT h e r e p l a c e m e n t s p a n w a s c o n s t r u c t e d o u t o fp r e s t r e s s e d g i r d e r s w i t h e x t r a w i d e f l a n g e s a n d h i g h -s t r e n g t h c o n c r e t e c l o s u r e p o u r s , a s s h o w n i n F i g u r e C -7 2 . T h i s d e s i g n w a s c h o s e n t o m i n i m i z e t h e a m o u n t o fc u r i n g t i m e f o r t h e d e c k o n c e a l l t h e g i r d e r s w e r e s e ti n t o p l a c e . T h e g i r d e r s u s e d l i g h t - w e i g h t c o n c r e t e t om a t c h t h e w e i g h t o f t h e o l d t r u s s – t h i s a l l o w e d t h eo r i g i n a l b e n t s t o b e u s e d , s a v i n g t i m e a n d m o n e y( W a s h i n g t o n S t a t e D O T 2 0 1 6 ) . O t h e r d e s i g n sc o n s i d e r e d f o r t h e r e p l a c e m e n t i n c l u d e d a s t e e l t h r o u g h -t r u s s ( t o m a t c h t h e r e m a i n i n g s p a n s ) , w h i c h w a sd e e m e d t o o t i m e - i n t e n s i v e , o r s t e e l p l a t e g i r d e r s w i t h ac o n c r e t e d e c k . U l t i m a t e l y , t h e w i n n i n g f i r m c h o s e t h ep r e s t r e s s e d c o n c r e t e d e s i g n .T h e r e p l a c e m e n t s p a n w a s c o n s t r u c t e d a l o n g s i d e t h eb r i d g e , a n d t h e n s l i d i n t o i t s f i n a l p o s i t i o n ; t h i s k e p tt r a f f i c f l o w i n g d u r i n g t h e c o n s t r u c t i o n a n d o n l yr e q u i r e d a f u l l c l o s u r e f o r o n e d a y t o p l a c e t h ep e r m a n e n t s p a n ( W a s h i n g t o n S t a t e D O T 2 0 1 3 ) . T h es l i d e u s e d v e r t i c a l a n d h o r i z t o n t a l j a c k i n g s y s t e m a l o n gw i t h a r a i l s y s t e m o n t o p o f t e m p o a r y b e n t s t o s h i f t t h es t r u c t u r e . ( W a s h i n g t o n S t a t e D O T 2 0 1 4 ) .C.17.5 ChallengesT h e d e c i s i o n t o u s e l i g h t w e i g h t c o n c r e t e f o r t h eg i r d e r s c r e a t e d s o m e c h a l l e n g e s , a s i t w a s d i f f i c u l t t om a i n t a i n t h e c o r r e c t a g g r e g a t e w e i g h t a n d m o i s t u r ec o n t e n t s , s o e x t r a a t t e n t i o n w a s p a i d t o t h e m i x d e s i g ni n t h e s e i n s t a n c e s . A l s o , t h e c l o s u r e p o u r d e s i g n h a d n o ty e t b e e n t h o r o u g h l y t e s t e d f o r d u r a b i l i t y , a s t h i s i s ar e l a t i v e l y n e w c o n s t r u c t i o n m e t h o d , a n d l a b o r a t o r y t e s t sh a v e n o t y e t b e e n c o n d u c t e d t o v e r i f y i t s l o n g e v i t y . T h i sd e s i g n i s s h o w n i n F i g u r e C - 7 3 . W S D O T m a y f i n d t h a tt h i s t e c h n i q u e d o e s n o t h a v e t h e l o n g e v i t y p r o m i s e d , b u tt i m e w i l l d e t e r m i n e i t s v i a b i l i t y a s a f u t u r e a l t e r n a t i v ed e s i g n ( W a s h i n g t o n S t a t e D O T 2 0 1 6 ) .Figure C-72. Prestressed Girders Lifting into Place (Washington State DOT 2014)Figure C-73. Closure Pours Connecting the Girders (Washington State DOT 2016)

190C.17.6 Innovations and Lessons LearnedC.17.6.1 A+B BiddingT h e d e c i s i o n t o u s e A + B B i d d i n g i n c o m b i n a t i o n w i t he a r l y m i l e s t o n e c o m p l e t i o n m i n i m i z e d t h e c o n s t r u c t i o nt i m e a n d p r o j e c t d e l a y s .C.17.6.2 Temporary Modular BridgeE r e c t i n g a t e m p o r a r y m o d u l a r b r i d g e , a s s h o w n i nF i g u r e C - 7 4 , r e d u c e d t h e n e e d f o r t r a f f i c d e t o u r s a r o u n dt h e c o l l a p s e d s t r u c t u r e . T h e n e a r b y b r i d g e s i n t h e t o w n s o fB u r l i n g t o n a n d M t . V e r n o n d i d n o t h a v e a d e q u a t e c a p a c i t i e s t o c a r r y i n t e r s t a t e t r a f f i c l e v e l s , s o t h e t e m p o r a r ys t r u c t u r e a l s o r e d u c e d t h e i m p a c t o n t h e s e c o m m u n i t i e sa n d e n s u r e d c o m m e r c e c o u l d p r o c e e d a s n o r m a l .C.17.6.3 Prefabricated Bridge Elements and Systems (PEBS)U s i n g P E B S i n t a n d e m w i t h c o n s t r u c t i n g t h e b r i d g e a d j a c e n t t o t h e t e m p o r a r y s t r u c t u r e m i n i m i z e d t r a f f i cd i s r u p t i o n a n d r e d u c e d t h e o v e r a l l l e n g t h o f c o n s t r u c t i o n t i m e . Figure C-74. Traffic Flow with Temporary Structures (Washington State DOT 2016)

191C.18 Pennsylvania Department of Transportation P3 2012[Procurement]Table C-18. Pennslyvania Department of Transportation P3Case Study Name/ Date Pennsylvania Department of Transportation P3 (2012)L ocation Pennsylvania, USAEvent Type Procurement Bridge Name Did not select one bridge for this Case Study/ NumerousScope/ Costs Repairs to 558 BridgesPlanning Techniques/ Tools ROW and permitting pre-approvalsEvent Response Formation of a Public-Private PartnershipAssessment Techniques/ Tools Criteria matrixRapid Restoration Type ABC using standardized drawings and prefabricated componentsInnovations • Public-Private Partnership• 28 -year build and maintenance contractC.18.1 IntroductionT o a d d r e s s t h e g r o w i n g i s s u e o f t h e C o m m o n w e a l t ho f P e n n s y l v a n i a ’ s 4 , 5 0 0 + p o o r l y r a t e d b r i d g e s , t h eP e n n s y l v a n i a D e p a r t m e n t o f T r a n s p o r t a t i o n( P e n n D O T ) f o r m e d a P u b l i c - P r i v a t e P a r t n e r s h i p ( P 3 )w i t h t h e P l e n a r y W a l s h K e y s t o n e P a r t n e r s ( P W K P )g r o u p . T h i s i n i t i a t i v e r e p l a c e d 5 5 8 b r i d g e s t h r o u g h o u tP e n n s y l v a n i a o v e r t h e c o u r s e o f t h r e e y e a r s . O n c e t h eb r i d g e s w e r e b u i l t , P W K P w i l l m a i n t a i n t h e b r i d g e s f o rt h e f o l l o w i n g 2 5 y e a r s , a n d t h e n a t t h e e n d o f t h e 2 8 -y e a r c o n t r a c t , w i l l h a n d t h e b r i d g e s b a c k o v e r t oP e n n D O T . M o s t o f t h e b r i d g e s i n v o l v e d i n t h e p r o j e c t a r e s m a l l r u r a l o r m e d i u m - s i z e d s t a t e - o w n e d b r i d g e s ,a n d n o t l a r g e i n t e r s t a t e s t r u c t u r e s . T h e r e p a i r s m o s t l y c o n s i s t e d o f A c c e l e r a t e d B r i d g e C o n s t r u c t i o n ( A B C )t o m e e t t h e t h r e e - y e a r d e a d l i n e . T h i s i n n o v a t i v e s o l u t i o n p a v e d t h e w a y f o r s i m i l a r c o n t r a c t s w i t h o t h e rD O T s l o o k i n g a t u n i q u e s o l u t i o n s t o h e l p r e p a i r t h e i r a g i n g i n f r a s t r u c t u r e ( P l e n a r y W a l s h K e y s t o n e P a r t n e r s2 0 1 9 ) . A f i n i s h e d b r i d g e t h r o u g h t h e p r o j e c t i s s h o w n i n F i g u r e C - 7 5 .C.18.2 Emergency PlanningC.18.2.1 Crowdsourcing and Information GatheringC l e a r c o m m u n i c a t i o n f r o m t h e s t a r t w a s u s e d t o k e e p g o o d r e l a t i o n s w i t h t h e p u b l i c . I t w a s d e c i d e d t h a ta w e b s i t e w o u l d b e c r e a t e d t o p r o v i d e r e g u l a r u p d a t e s o n c l o s u r e s o r d e t o u r r e - r o u t e s t o h e l p k e e p t r a f f i cf l o w i n g a n d r e d u c e d i s r u p t i o n t o c o m m e r c e . F u r t h e r m o r e , t h e d e s i g n l i v e s o f t h e b r i d g e s w e r e a l l 1 0 0 y e a r s ;t h i s l i f e s p a n w a s c h o s e n t o r e d u c e f u t u r e t r a f f i c i m p a c t s . ( P l e n a r y W a l s h K e y s t o n e P a r t n e r s 2 0 1 9 ) .Figure C-75. A Bridge Built part of the P3 Project (Plenary Walsh Keystone Partners2019)

192C.18.3 AssessmentT o d e t e r m i n e w h i c h b r i d g e s q u a l i f i e d f o r t h e p r o j e c t , P e n n D O T i n v e s t i g a t e d o v e r 2 , 0 0 0 o f i t s p o o r l yr a t e d b r i d g e s . B r i d g e a g e , t y p e , s i z e , a v e r a g e d a i l y t r a f f i c , a n d e n v i r o n m e n t a l i m p a c t s w e r e k e y f a c t o r s i nt h e d e c i s i o n . T h e s t a n d a r d i z e d A B C a p p r o a c h p a i r e d b e s t w i t h s m a l l e r , s i n g l e , o r d o u b l e s p a n b r i d g e s , s ot h i s d e s c r i p t i o n h e l p e d n a r r o w d o w n t h e s e l e c t i o n o f t h e f i n a l 5 5 8 ( P l e n a r y W a l s h K e y s t o n e P a r t n e r s 2 0 1 9 ) .C.18.4 Rapid RestorationC.18.4.1 ContractingT h e P 3 m o d e l w a s m a d e p o s s i b l e b y G o v e r n o r T o m C o r b e t t i n 2 0 1 2 , w h e n h e s i g n e d t h e P A G e n e r a lA s s e m b l y i n t o e f f e c t , w h i c h a i m s t o r a p i d l y i m p r o v e P e n n s y l v a n i a ’ s a g i n g i n f r a s t r u c t u r e , a n d t o s a v e t h et a x p a y e r s m o n e y . I t i s m o r e i n e x p e n s i v e t o g r o u p t h e 5 0 0 + b r i d g e s i n t o o n e g i a n t c o n t r a c t , r a t h e r t h a nc o m p l e t i n g i n d i v i d u a l o n e s . F u r t h e r m o r e , t h e c o o k i e - c u t t e r a p p r o a c h m a y c o s t m o r e u p f r o n t , b u ts i g n i f i c a n t l y r e d u c e s p e n d i n g l a t e r i n t h e p r o j e c t ( P l e n a r y W a l s h K e y s t o n e P a r t n e r s 2 0 1 9 ) . A n e x a m p l e o fa c o m p l e t e d b r i d g e i s s h o w n i n F i g u r e C - 7 6 .P W K P g r o u p i s m a d e u p o f t h e f o l l o w i n g c o m p a n i e s :• H D R , I n c – l e a d d e s i g n f i r m• W a l s h I n f r a s t r u c t u r e M a n a g e m e n t – m a i n t e n a n c e c r e w f o r e n t i r e c o n t r a c t• W a l s h / G r a n i t e J V – l e a d c o n t r a c t o r• P l e n a r y G r o u p U S A L t d . + W a l s h I n v e s t o r s , L L C – f i n a n c e g r o u p sT h r o u g h o u t t h e c o n t r a c t , t h e P e n n s y l v a n i aD e p a r t m e n t o f T r a n s p o r t a t i o n r e m a i n e d o w n e r s o f t h eb r i d g e s ( P l e n a r y W a l s h K e y s t o n e P a r t n e r s 2 0 1 9 ) .T o e n c o u r a g e m o r e i n v o l v e m e n t f r o m o t h e rc o m p a n i e s , o u t r e a c h o p p o r t u n i t i e s t o t h e d i s a d v a n t a g e db u s i n e s s e n t e r p r i s e ( D B E ) c o m m u n i t y w e r e o r g a n i z e d .T h e s e m e e t i n g s p r o v i d e d i n f o r m a t i o n a s t o h o w t h e s es m a l l e r s u b c o n t r a c t o r s c o u l d b e c o m e i n v o l v e d i n t h ep r o j e c t ( P l e n a r y W a l s h K e y s t o n e P a r t n e r s 2 0 1 9 ) .T o f i n a n c e t h e c o n s o r t i u m , p e r f o r m a n c e - b a s e dp a y m e n t s w e r e m a d e p e r i o d i c a l l y t h r o u g h o u t t h ec o n t r a c t . M o r e m o n e y w a s p a i d u p f r o n t d u r i n g t h e b u l ko f t h e c o n s t r u c t i o n , a n d t h e n t a p e r e d a s t h e r e s p o n s i b i l i t y s h i f t e d t o w a r d m a i n t e n a n c e ( P l e n a r yW a l s h K e y s t o n e P a r t n e r s 2 0 1 9 ) .C.18.4.2 Permanent StructureT o s p e e d u p t h e r e p a i r p r o c e s s , R i g h t o f W a y ( R O W ) a n d o t h e r p e r m i t s w e r e a t t a i n e d p r i o r t oc o n s t r u c t i o n . B r i d g e s w e r e s c r e e n e d i n b a t c h e s t o e x p e d i t e t h e p r o c e s s f u r t h e r ( P l e n a r y W a l s h K e y s t o n eP a r t n e r s 2 0 1 9 ) .T o b e a b l e t o r a p i d l y r e p a i r 5 5 8 b r i d g e s , t h e g r o u p d e v e l o p e d s t a n d a r d i z e d d e s i g n s w h i c h u s e d m a n yp r e f a b r i c a t e d c o m p o n e n t s t h a t w e r e c r e a t e d o f f - s i t e . T h e s e p r e f a b r i c a t e d u n i t s w e r e t r u c k e d t o t h e s i t e s a n dq u i c k l y i n s t a l l e d u s i n g A B C t e c h n o l o g i e s ( P l e n a r y W a l s h K e y s t o n e P a r t n e r s 2 0 1 9 ) .Figure C-76. A Bridge Built part of the P3 Project (Plenary Walsh Keystone Partners2019)

193C.18.5 ChallengesO n e c h a l l e n g e w i t h t h i s p r o j e c t w a s t o p r e v e n t t h e a p p e a r a n c e o f t h e f o r m a t i o n o f a m o n o p o l y o nP e n n s y l v a n i a b r i d g e r e p a i r s . T h e c o n s o r t i u m g a i n e d t h e “ r i g h t s ” t o r e p a i r h u n d r e d s o f b r i d g e s , l e a v i n g o t h e rc o n s t r u c t i o n a n d d e s i g n f i r m s o u t o f l u c k . H o w e v e r , t h e d e c i s i o n t o e x p a n d t h e p r o g r a m t o i n c l u d e D B Ec o m p a n i e s o p e n e d t h e d o o r f o r o t h e r s t o t a k e p a r t , s p r e a d i n g t h e w e a l t h a n d p r e v e n t i n g t h e f o r m a t i o n o f am o n o p o l y .A d d i t i o n a l l y , t h e d e v e l o p m e n t o f s t a n d a r d p l a n s t h a t w o u l d w o r k f o r m u l t i p l e b r i d g e s w a s a l s oc h a l l e n g i n g . B y g r o u p i n g s i m i l a r b r i d g e s t o g e t h e r , t h e y c o n s o r t i u m a s a b l e t o d e t e r m i n e t h e n u m b e r o f p l a ns e t s r e q u i r e d , a n d t o a l s o s p e e d u p t h e w o r k .C.18.6 Innovations and Lessons LearnedC.18.6.1 Application of P3 ModelM o s t o f t h e l e s s o n s l e a r n e d w i t h t h i s p r o j e c t w e r ef r o m t h e p r o c u r e m e n t a n d a s s e t s e l e c t i o n s t a g e s .A c q u i r i n g m a t e r i a l s c a n b e c h a l l e n g i n g , e s p e c i a l l yw h e n m a s s q u a n t i t i e s a r e r e q u i r e d f o r s t a n d a r dc o m p o n e n t s . M o r e o v e r , l e a r n i n g h o w t o m a n a g e am u l t i - c o m p a n y p r o j e c t , s u c h a s d e t e r m i n i n g w h oo v e r s e e s w h a t , a n d w h i c h c o m p a n y ( i e s ) a r e r e s p o n s i b l ef o r w h i c h p o r t i o n s c a n b e c h a l l e n g i n g . T h e g o a l o f t h i sp r o j e c t w a s t o n o t o n l y r e p a i r h u n d r e d s o f p o o r l y r a t e db r i d g e s , b u t t o a l s o l e a r n h o w t o i m p l e m e n t t h e P u b l i c -P r i v a t e P a r t n e r s h i p . T h e P 3 m o d e l c o u l d b e e x p a n d e dt o o t h e r p r o j e c t s o r s t a t e s , s o P e n n D O T r e a l l y f o c u s e d o n l e a r n i n g t h e l o g i s t i c a l s i d e o f t h e p r o j e c t a n du n d e r s t a n d i n g w h a t w o r k e d a n d w h a t d i d n o t ( P e n n D O T P 3 P a r t n e r s h i p s 2 0 1 9 ) . F i g u r e C - 7 7 s h o w s a ne x a m p l e o f a b r i d g e f i n i s h e d t h r o u g h t h e p r o j e c t .Figure C-77. A Bridge Built part of the P3 Project (Plenary Walsh Keystone Partners2019)

194C.19 I-35W Mississippi River Bridge Collapse 2007 [Man-made]Table C-19. I-35W Missippi River Bridge Collapse Case Study Name/ Date I-35W Mississippi River Bridge Collapse (2007 )L ocation Minnesota, USAEvent Type Man-madeBridge Name I-35W Mississippi River BridgeScope/ Costs 456’ of main span deck truss + surrounding spans collapsed into Mississippi River, impacting all 8 lanesPlanning Techniques/ Tools 911 CallsEvent Response Unified Command System ImplementedAssessment Techniques/ Tools Collapse video, photos, eyewitness testimonyRapid Restoration Type Precast segmental bridge constructionInnovations • Structural health monitoring of the replacement bridge• Connection inspectionsC.19.1 IntroductionT h e o r i g i n a l f o u r t e e n s p a n I - 3 5 W M i s s i s s i p p i R i v e rB r i d g e w a s o p e n e d i n 1 9 6 7 b y T h e M i n n e s o t aD e p a r t m e n t o f T r a n s p o r t a t i o n ( M n D O T ) , a s s h o w n i nF i g u r e C - 7 8 . T h e s t r u c t u r e c a r r i e d b o t h n o r t h b o u n d a n ds o u t h b o u n d t r a f f i c . U n k n o w n a t t h e t i m e , t h e c e n t e rd e c k t r u s s p o r t i o n w a s c o n n e c t e d b y u n d e r - d e s i g n e dg u s s e t p l a t e s . F u r t h e r m o r e , t h e b r i d g e h a d b e e n d e e m e ds t r u c t u r a l l y d e f i c i e n t s i n c e 1 9 9 1 ( N a t i o n a lT r a n s p o r t a t i o n S a f e t y B o a r d 2 0 0 7 ) .O n A u g u s t 1 s t , 2 0 0 7 , t h e I - 3 5 W B r i d g e c o l l a p s e d d u et o a g u s s e t p l a t e f a i l u r e o n t h e m a i n s p a n , a s s h o w n i nF i g u r e C - 7 9 . 1 1 1 v e h i c l e s w e r e i n v o l v e d , 1 3 p e o p l ed i e d , a n d 1 4 5 w e r e i n j u r e d . T h e N T S B r u l e d t h ec o l l a p s e w a s d u e t o d e s i g n e r e r r o r a n d l a c k o f q u a l i t yc o n t r o l o f t h e g u s s e t p l a t e , w h i c h f a i l e d d u e t o i n c r e a s e dl o a d i n g f r o m c o n s t r u c t i o n e q u i p m e n t / s u p p l i e s i nc o m b i n a t i o n w i t h p r e v i o u s b r i d g e m o d i f i c a t i o n s a n d a ni n s u f f i c i e n t d e s i g n c a p a c i t y . I n t o t a l , a b o u t 1 0 0 0 ’ o f t h eb r i d g e c o l l a p s e d i n t o t h e M i s s i s s i p p i R i v e r .A r e p l a c e m e n t b r i d g e w a s b u i l t s h o r t l y a f t e r t h ec o l l a p s e , a n d r e m o t e s e n s i n g t e c h n o l o g y w a si m p l e m e n t e d t o m o n i t o r t h e h e a l t h o f t h e s t r u c t u r e a n da l e r t o f f i c i a l o f p o s s i b l e c h a n g e s t o t h e s u b s t r u c t u r ec o n d i t i o n s ( C o l l i n s e t a l . 2 0 1 4 ) .C.19.1.1 Event ResponseF i r s t r e s p o n d e r s r e q u e s t e d a l l a v a i l a b l e p e r s o n n e l t o a i d i n r e s c u e e f f o r t s . A b o u t 1 0 0 c i t i z e n s h e l p e d f i r s tr e s p o n d e r s r e s c u e t h o s e i n v o l v e d i n t h e c o l l a p s e . L o c a l h o s p i t a l s w e r e n o t i f i e d s h o r t l y t h e r e a f t e r , a n d t h i sFigure C-78. I-35W Bridge Prior to Collapse(National Transportation Safety Board 2007) Figure C-79. Aerial View After the Collapse (National Transportation Safety Board 2007)

195w a s o r g a n i z e d b y t h e H e n n e p i n C o u n t y M e d i c a l c e n t e r . O n l y 5 m i n u t e s a f t e r t h e f i r s t c a l l , t h e H e n n e p i nC o u n t y S h e r i f f ’ s O f f i c e h a d e s t a b l i s h e d a U n i f i e d C o m m a n d P o s t i n t h e p a r k i n g l o t o f t h e n e a r b y R e d C r o s sf a c i l i t y , a n d t h e y a l s o s e t u p a R i v e r I n c i d e n t C o m m a n d ( N a t i o n a l T r a n s p o r t a t i o n S a f e t y B o a r d 2 0 0 7 ) .T h e d a y a f t e r t h e i n c i d e n t , t h e U S C o a s t G u a r d e s t a b l i s h e d a s e c u r i t y z o n e f o r t h e M i s s i s s i p p i R i v e r , a n do n l y e m e r g e n c y v e s s e l s w e r e p e r m i t t e d t o e n t e r . I n i t i a l w o r r i e s w e r e o f a t e r r o r i s t a t t a c k , s o i t w a s r u l e d ac r i m e s c e n e b y t h e M i n n e a p o l i s P o l i c e D e p a r t m e n t . T h e U n i f i e d C o m m a n d S y s t e m i m p l e m e n t e d , p e r t h er u l e s o f t h e c i t y o f M i n n e a p o l i s , w e r e d e e m e d a p p r o p r i a t e b y t h e N T S B d u r i n g a n a l y s i s . R e c o v e r y e f f o r t sc o n t i n u e d i n t h e w a t e r u n t i l A u g u s t 6 t h w h e n t h e l a s t v i c t i m w a s f o u n d . R i v e r t r a f f i c d i d n o t r e t u r n t o n o r m a lu n t i l O c t o b e r 6 t h ( N a t i o n a l T r a n s p o r t a t i o n S a f e t y B o a r d 2 0 0 7 ) .C.19.2 Emergency PlanningC.19.2.1 Crowdsourcing and Information GatheringT h e M i n n e a p o l i s F i r e a n d P o l i c e D e p a r t m e n t s w e r ed i s p a t c h e d a f t e r a 9 1 1 c a l l w a s r e c e i v e d . T h e c o l l a p s ew a s c o n f i r m e d b y M n D O T f r e e w a y c a m e r a s .E y e w i t n e s s t e s t i m o n y , a s e c u r i t y c a m e r a c a p t u r e dc o l l a p s e v i d e o , a n d a p h o t o g r a p h f r o m a c o m m e r c i a la i r l i n e p a s s e n g e r , a s s h o w n i n F i g u r e C - 8 0 , w e r eg a t h e r e d a f t e r t h e i n c i d e n t t o p a i n t t h e p i c t u r e o f t h ec o l l a p s e .C.19.3 AssessmentT h e c o l l a p s e w a s c a p t u r e d o n a s e c u r i t y c a m e r a f r o m t h e L o w e r S t . A n t h o n y F a l l s L o c k a d j a c e n t t o t h eb r i d g e . T h i s v i d e o s h o w e d t h e s o u t h e n d o f s p a n 7 ( t h e m i d d l e s p a n ) s h o w i n g s i g n s o f f a i l u r e f i r s t , i n d i c a t i n gt h i s r e g i o n w a s t h e c a u s e o f t h e c o l l a p s e . B e c a u s e o f t h i s i n f o r m a t i o n , r e c o v e r y e f f o r t s f o c u s e d o n t h a t a r e af o r c l o s e r i n s p e c t i o n .T h e t r u s s p o r t i o n s w e r e r e m o v e d f r o m t h e r i v e r a n d l a t e r a n a l y z e d f o r d e f e c t s o r a n y o t h e r s i g n s t h a tc o u l d p i n p o i n t t h e l o c a t i o n o f f a i l u r e . T h e d a m a g e i n d i c a t e d t h e g u s s e t p l a t e s w e r e t h e i n i t i a l l o c a t i o n o fc o l l a p s e .A p a s s e n g e r i n a c o m m e r c i a l f l i g h t c a p t u r e d a p i c t u r e o f t h e b r i d g e a f e w h o u r s b e f o r e t h e c o l l a p s e . T h i sp h o t o s h o w e d w h e r e c o n s t r u c t i o n c r e w s a n d s t a g i n g m a t e r i a l s w e r e l o c a t e d o n t h e b r i d g e . T h i s i nc o m b i n a t i o n w i t h e y e w i t n e s s t e s t i m o n y w a s u s e d t o d e t e r m i n e t h e e x a c t l o c a t i o n o f t h e s e m a t e r i a l s , a s t h ee x t r a w e i g h t w a s l a t e r s u s p e c t e d a s p a r t o f t h e c a u s e o f c o l l a p s e .A n a n a l y s i s w a s p e r f o r m e d o n t h e s u s p e c t e d g u s s e t p l a t e s a f t e r t h e c o l l a p s e . S t r e s s t e s t s w e r e c o n d u c t e du s i n g t h e s a m e d e m a n d s t h a t w o u l d h a v e b e e n i m p o s e d o n t h e b r i d g e a t t h e t i m e o f f a i l u r e . I t w a sd e t e r m i n e d t h a t s e v e r a l o f t h e p l a t e s h a d a c a p a c i t y l e s s t h a n t h e d e m a n d , s o m e o n t h e o r d e r o f 2 x l e s s i nt h e c a s e s o f s h e a r . T h e s e d e f i c i e n c i e s w e r e n o t c a u s e d b y a n i n c r e a s e d l o a d o n t h e b r i d g e b u t w e r e d e f i c i e n tf o r e v e n t h e o r i g i n a l d e s i g n b r i d g e l o a d s ( N a t i o n a l T r a n s p o r t a t i o n S a f e t y B o a r d 2 0 0 7 ) .Figure C-80. Aerial View a Few Hours Before the Crash (National Transportation Safety Board 2007)

196C.19.4 Rapid RestorationC.19.4.1 ContractingA f t e r t h e c o l l a p s e o f t h e I - 3 5 B r i d g e , t h e s t e p s t a k e n r e q u i r e di m m e d i a t e a c t i o n t o r e b u i l d t h e b r i d g e q u i c k l y . T h e f i r s t s t e p i nr e c o n s t r u c t i o n w a s a c q u i r i n g t h e l a n d n e c e s s a r y t o b u i l d . T o e x p e d i t et h i s p r o c e s s , t h e M i n n e s o t a D O T u s e d a “ t w o - s t e p r i g h t - o f - w a ya c q u i s i t i o n . ” T h i s a l l o w e d t h e D O T i m m e d i a t e a c c e s s t o t h ec o n s t r u c t i o n s i t e a s w e l l a s a g u a r a n t e e d t i m e l i n e f o r f i n a n c i a l c l o s u r eo n e a c h p i e c e o f l a n d . T o c o m p l e t e t h i s p r o j e c t r a p i d l y a n d t o m i n i m i z ea n y d e l a y s c a u s e d b y p e r m i t c o n s t r a i n t s , a w e l l - d e f i n e d s c o p e w a sn e e d e d . D u r i n g t h e b i d d i n g p r o c e s s t o s e l e c t a D e s i g n - B u i l d e r , t h eM n D O T w a s h i g h l y i n t e r a c t i v e a n d c o n d u c t e d m u l t i p l e o n e - o n - o n em e e t i n g s w i t h e a c h c o m p e t i t o r t o k e e p i d e a s a n d d e s i g n s c o n f i d e n t i a l .T h e M n D O T a l s o c r e a t e d a t r a n s p a r e n t e v a l u a t i o n p l a n w i t h i n c e n t i v e sf o r t i m e l y c o m p l e t i o n a n d s u c c e s s . T h e n e w I - 3 5 W b r i d g e w a sc o m p l e t e d 3 3 9 d a y s a f t e r c o n s t r u c t i o n b e g a n , a l m o s t t h r e e m o n t h sa h e a d o f s c h e d u l e . T h e b i d d i n g t i m e l i n e i s s h o w n i n F i g u r e C - 8 1 .C.19.4.2 DesignT h e n e w r e p l a c e m e n t s t r u c t u r e , c a l l e d t h e S t . A n t h o n y F a l l s B r i d g e ,w a s d e s i g n e d t o m a x i m i z e s a f e t y a n d q u a l i t y w i t h i n p u t f r o m t h e l o c a lc o m m u n i t i e s v i a a d a y l o n g d e s i g n c h a r r e t t e . T h e d e s i g n t e a m l i s t e n e d t o t h e i n p u t f r o m e i g h t y - e i g h t c i t i z e n sa n d g o v e r n m e n t o f f i c i a l w h o h e l p e d d e c i d e o n e s s e n t i a l a e s t h e t i c s f e a t u r e s i n c l u d i n g t h e c u r v e d s h a p e dp i e r s a n d a s i g n a t u r e l i g h t i n g s c h e m e f o r t h e b r i d g e . T h e n e w b r i d g e d e s i g n p l a c e d a s t r o n g e m p h a s i s o nr e d u c i n g l o n g - t e r m m a i n t e n a n c e c o s t s a n d i n c l u d e d s e v e r a l l e v e l s o f s t r u c t u r a l r e d u n d a n c y a n d l o n g - t e r ms t r u c t u r a l h e a l t h m o n i t o r i n g . S e n s o r s w e r e b u i l t i n t o t h e b r i d g e t o b r o a d c a s t r e a l t i m e i n f o r m a t i o n a b o u t t h eb r i d g e p e r f o r m a n c e a n d p r o v i d e d a t a d u r i n g c o n s t r u c t i o n . T h e c o n s t r u c t i o n o f t h i s b r i d g e t o o k a d v a n t a g eo f l o c a l l a b o r , l o c a l m a t e r i a l s , a n d u s e d p r e c a s t i n g t e c h n i q u e s t o m i n i m i z e c o s t a n d r e d u c e e n v i r o n m e n t a li m p a c t s . C o n s t r u c t i n g m o s t o f t h e b r i d g e o n l a n d r e d u c e d t h e a m o u n t o f c o n s t r u c t i o n w a s t e t h a t e n t e r e d t h er i v e r ( C h i g l o & F i g g 2 0 0 8 , F i g g & P h i p p s 2 0 0 8 ) .C.19.4.3 Permanent StructureT h e n e w S t . A n t h o n y F a l l s b r i d g e c o n s i s t s o f t w i n c o n c r e t e s t r u c t u r e s t h a t a r e 1 , 2 2 3 f e e t i n l e n g t h a n du t i l i z e d t w o b o x g i r d e r s i n e a c h s t r u c t u r e . T h e 5 0 4 - f o o t - l o n g m a i n s p a n s u s e d p r e c a s t s e g m e n t a lc o n s t r u c t i o n t e c h n i q u e s a n d t h e s i d e s p a n s w e r e c a s t - i n - p l a c e . E a c h c o n c r e t e s t r u c t u r e i s a p p r o x i m a t e l yn i n e t y f e e t i n w i d t h a n d s u p p o r t s f i v e l a n e s i n e a c h d i r e c t i o n . T h e 1 2 0 p r e c a s t s u p e r s t r u c t u r e s e g m e n t sv a r i e d i n b o t h l e n g t h ( t h i r t e e n a n d a h a l f f e e t t o t w e n t y - f i v e f e e t ) a n d d e p t h ( e l e v e n f e e t a t m i d s p a n a n dt w e n t y - f i v e f e e t a t p i e r s ) . E i g h t l o n g l i n e c a s t i n g b e d s w e r e c o n s t r u c t e d o n t h e e x i s t i n g I - 3 5 W r o a d w a y t of a b r i c a t e t h e p r e c a s t s u p e r s t r u c t u r e . T h e p r o x i m i t y o f t h e c a s t i n g y a r d s t r e a m l i n e d t r a n s p o r t a t i o n o f t h ep r e c a s t e l e m e n t a n d s i m p l i f i e d t h e c o o r d i n a t i o n b e t w e e n t h e c o n s t r u c t i o n c r e w a n d t h e e n g i n e e r i n g t e a m( F i g g & P h i p p s 2 0 0 8 ) .T h e b r i d g e f o u n d a t i o n i s c o m p o s e d o f a t o t a l o f 1 0 9 d r i l l e d s h a f t s . T h e d i a m e t e r o f t h e s h a f t s r a n g e d f r o mf o u r t o e i g h t f e e t i n d i a m e t e r a n d w e r e u p t o n i n e t y - f i v e f e e t d e e p . T h i s f o u n d a t i o n t y p e w a s c h o s e n t or e d u c e t h e n u m b e r o f o p e r a t i o n s a n d r e d u c e c o n s t r u c t i o n t i m e . F o u r d r i l l r i g s o p e r a t e d s i m u l t a n e o u s l y t oc o m p l e t e t h e f o u n d a t i o n a s r a p i d l y a s p o s s i b l e . S e l f - c o n s o l i d a t i n g c o n c r e t e w i t h a d e s i g n s t r e n g t h o f 5 0 0 0p s i w a s u s e d f o r t h e s h a f t s t o s p e e d p l a c e m e n t a n d e n s u r e q u a l i t y ( F i g g & P h i p p s 2 0 0 8 ) .Figure C-81. Bidding Timeline (Hieptas 2008)

197T h e f o u r m a i n p i e r f o o t i n g s s p a n n e d p o r t i o n s o f t h e p r e v i o u s b r i d g e ’ s f o u n d a t i o n , d r a i n a g e t u n n e l s , a n de x i s t i n g u t i l i t i e s . T h e c u r i n g o f t h e s e m a s s c o n c r e t e f o o t i n g s w a s c o n t r o l l e d u s i n g e m b e d d e d c o o l i n g p i p e sa n d a c u s t o m c o n c r e t e m i x . E a c h f o o t i n g s u p p o r t e d t w o 7 0 - f o o t c o n c r e t e p i e r s a n d t w o b o x g i r d e r s . T h ec u r v e d s h a p e o f t h e p i e r s m a t c h e d t h e t a p e r o f t h e v a r i a b l e d e p t h b o x g i r d e r s ( F i g g & P h i p p s 2 0 0 8 ) .T h e b o x g i r d e r s u p e r s t r u c t u r e i n c l u d e d c a s t - i n - p l a c es i d e s p a n s a n d a p r e c a s t s e g m e n t a l m a i n s p a n t h a tc r o s s e d t h e r i v e r . C o n s t r u c t i o n o p e r a t i o n s o f t h e s i d es p a n s a n d p r e c a s t m a i n s p a n s e g m e n t s o c c u r r e ds i m u l t a n e o u s l y t o r e d u c e t h e o v e r a l l c o n s t r u c t i o n t i m e .I n a d d i t i o n , t h e e i g h t l o n g - l i n e c a s t i n g b e d s w e r eo p e r a t e d s i m u l t a n e o u s l y . O n c e t h e p r e c a s t s e g m e n t sw e r e c o n s t r u c t e d , t h e y w e r e t r a n s p o r t e d a n d s t o r e da d j a c e n t t o t h e r i v e r u n t i l i t w a s t i m e t o i n s t a l l t h e m .S e g m e n t s w e r e t h e n d e l i v e r e d t o t h e s i t e b y b a r g e a n dl i f t e d w i t h a b a r g e - m o u n t e d c r a n e a s s h o w n i n F i g u r eC - 8 2 . T h e 1 2 0 p r e c a s t s e g m e n t s w e r e e r e c t e d i n f o r t y -s e v e n d a y s . M i d s p a n c l o s u r e p o u r s c o n n e c t t h ec a n t i l e v e r s p a n s f r o m o p p o s i t e s i d e s o f t h e r i v e r . E a c hp a i r o f a d j a c e n t p r e c a s t s e g m e n t s w e r e c o n n e c t e d w i t ha l o n g i t u d i n a l c l o s u r e p o u r . T h e e n t i r e b r i d g e d e c k w a s t r a n s v e r s e l y p o s t - t e n s i o n e d t o a d d d u r a b i l i t y t o t h er i d i n g s u r f a c e ( F i g g & P h i p p s 2 0 0 8 ) .C.19.5 ChallengesM n D O T w a n t e d t o k e e p t h e s c o p e o f t h e b r i d g e s m a l l a n d d e f i n e d t o s t a y w i t h i n s p e c i f i c p e r m i t t i n g l i m i t st h r o u g h “ C a t e g o r i c a l E x c l u s i o n . ” T h i s k i n d o f p e r m i t a l l o w e d t h e D O T t o c o m p l e t e s m a l l t a s k s w i t h o u t a ne n v i r o n m e n t a l i m p a c t a s s e s s m e n t . I f M n D O T v i o l a t e dt h i s p e r m i t , i t w o u l d h a v e r e s u l t e d i n a n i n c r e a s e dp r o j e c t d u r a t i o n . ( G r a n s b e r g & L o u l a k i s 2 0 1 2 ) .C.19.6 Innovations and Lessons LearnedC.19.6.1 Inspection GuidelinesD u r i n g r o u t i n e l o a d r a t i n g s , c o n n e c t i o n s s u c h a sg u s s e t p l a t e s s h o u l d b e e v a l u a t e d , e v e n t h o u g h t h e y a r en o t p a r t o f t h e A A S H T O s t a n d a r d p r o c e d u r e . A l s o , n e wb r i d g e s s h o u l d b e l o a d r a t e d , d e s p i t e t h e l a c k o fr e q u i r e m e n t b y A A S H T O a s w e l l . T h e i m p l e m e n t a t i o no f h e s e t w o s u g g e s t i o n s c o u l d h a v e p r e v e n t e d t h ed i s a s t e r a l t o g e t h e r . M o r e o v e r , t h e r e i s n o c l e a r n a t i o n a l g u i d a n c e o n c o n s t r u c t i o n l o a d s , w h i c h s h o u l d b ec o n s i d e r e d b e f o r e a n y a l t e r a t i o n s o r e q u i p m e n t i s p l a c e d o n a s t r u c t u r e , a n d c o n t r a c t o r s a r e e x p e c t e d t oh a v e d u e d i l i g e n c e b e f o r e s t a r t i n g w o r k ( N a t i o n a l T r a n s p o r t a t i o n S a f e t y B o a r d 2 0 0 7 ) .Figure C-83. Computer Rendering of Replacement Bridge (Collins et al. 2014)Figure C-82. Placement of Main Span Precast Segments (Figg & Phipps 2008)

198C.19.6.2 Structural Health MonitoringR e m o t e s e n s i n g t e c h n o l o g i e s w e r e i n c l u d e d w i t h t h ec o n s t r u c t i o n o f t h e n e w b r i d g e t o e n a b l e b e t t e r s t r u c t u r a lm o n i t o r i n g a n d p r e p a r a t i o n f o r a n o t h e r d i s a s t e r ,w h e t h e r i t b e a c o l l i s i o n o r e x t r e m e w e a t h e r e v e n t .D u r i n g c o n s t r u c t i o n t h e r m a l m o n i t o r i n g w a s u s e d t om o n i t o r t h e c u r i n g o f t h e m a s s c o n c r e t e e l e m e n t s ( i . e . ,d r i l l e d s h a f t s a n d p i e r f o o t i n g s ) . T h e s e d e v i c e s w e r ep l a c e d o n t h e r e i n f o r c e m e n t p r i o r t o p o u r i n g c o n c r e t e ,a s s h o w n i n F i g u r e C - 8 3 a n d F i g u r e C - 8 4 . C o n s t r u c t i o nl o a d m o n i t o r i n g w a s a l s o u s e d i n t h e b r i d g e d u r i n ge r e c t i o n , w h i c h i n c l u d e d s t r a i n g a u g e s a t t a c h e d t o t h er e i n f o r c e m e n t s . L a s t l y , l o n g - t e r m m o n i t o r i n g a f t e r t h es t r u c t u r e c o m p l e t i o n w a s i m p l e m e n t e d , i n c l u d i n g l i v el o a d t r u c k t e s t s , d e c k c o r r o s i o n , b o x g i r d e r v i b r a t i o n a n ds t r a i n m o n i t o r i n g . T h e r e s u l t s f r o m t h e s e n s o r s h a v es h o w n t h e a b i l i t y t o d e t e c t m i n u t e c h a n g e s w i t h i n t h es t r u c t u r e , w h i c h c a n b e u s e d t o p r e v e n t a m a j o r e m e r g e n c y e v e n t s u c h a s a n o t h e r c o l l a p s e ( C o l l i n s e t a l .2 0 1 4 ) .Figure C-84. in Gauges on the Reinforcement of Replacement Bridge (Collins et al. 2014)

199C.20 Rapid Repair of Sava River Bridge at Brcko 1996 [Man-made]Table C-20. Rapid Repair of Sava River Bridge at BrckoCase Study Name/ Date Sava River Bridge at Brcko (1996)L ocation Brcko, BosniaEvent Type Man-made (explosion)Bridge Name Sava River Bridge at BrckoScope/ Costs Three 20m spans and one 35m span; total cost N/ APlanning Techniques/ Tools Military L oad Class RatingEvent Response N/ AAssessment Techniques/ Tools V isual Inspections, Hammer sounding, and measurementsRapid Restoration Type Portable modular prefabricated panel truss (i.e., Bailey Bridge) Innovations • Use of panel trusses that rest on top of existing bridgesubstructures• Military L oad Class Rating due to lack of bridge plansC.20.1 IntroductionT h e h i s t o r i c S a v a R i v e r B r i d g e a t B r c k o w a s b u i l t i n 1 8 9 4 . T h e b r i d g e w a s 8 0 0 m l o n g a n d o r i g i n a l l ys e r v e d a s a r a i l r o a d b r i d g e u n t i l i t w a s c o n v e r t e d t o v e h i c u l a r t r a f f i c i n 1 9 8 5 . T h e o r i g i n a l b r i d g e s e r v e d a sa m a j o r s u p p l y r o u t e , a n d i t w a s d e s t r o y e d f r o m w a r f a r e i n t h e 1 9 9 0 s b y e x p l o s i v e s , a s s h o w n i n F i g u r e C -8 5 . I n 1 9 9 6 , a n i n t e r n a t i o n a l t e a m o f U S m i l i t a r y e n g i n e e r s a n d c i v i l i a n c o n t r a c t o r s w e r e s e n t t o r e s t o r e t h ep a r t i a l l y c o l l a p s e d b r i d g e . T h e c o n s t r u c t i o n n e e d e d t o b e c o m p l e t e d b e f o r e w i n t e r w e a t h e r a r r i v e d a n d t h ea n n u a l s p r i n g f l o o d s b e g a n . A m o d u l a r b r i d g e s y s t e m w a s u s e d t o r e s t o r e t h e b r i d g e t o t e m p o r a r y , o n e - w a yt r a f f i c . T h e r a p i d r e p a i r c o n s t r u c t i o n t o o k p l a c e i n 2 0 d a y s .C.20.2 Emergency PlanningC.20.2.1 Crowdsourcing and Information GatheringB r i d g e p l a n s w e r e n o t a v a i l a b l e , s o m i l i t a r y e n g i n e e r s h a d t o r e l y o n t h e l o c a l c o m m u n i t y t o u n d e r s t a n dh o w t h e b r i d g e f u n c t i o n e d p r i o r t o d a m a g e , s u c h a s i f t h e b r i d g e e x p e r i e n c e a n y s e v e r e s h a k i n g o r m a d en o i s e d u r i n g r o u t i n e u s e . T h e u s e o f p u b l i c f e e d b a c k o n t h e b r i d g e ’ s p e r f o r m a n c e a f t e r t h e c o n s t r u c t i o n w a sc r u c i a l t o e n s u r e t h e b r i d g e w a s r e p a i r e d p r o p e r l y .Figure C-85. Elevation of Save River Bridge at Brcko (with permission from ASCE, Mlakar & Ray 1997)

200C.20.3 AssessmentI n i t i a l i n s p e c t i o n s r e v e a l e d s e v e r a l c o l l a p s e d s p a n s , b u t t h e f u l l e x t e n t o f t h e d a m a g e s w a s u n k n o w n w i t ha s i m p l e v i s u a l i n s p e c t i o n . T h e b r i d g e w a s l o a d r a t e d u s i n g t h e M i l i t a r y L o a d C l a s s ( M L C ) p r o c e d u r e ,w h i c h f o u n d t h a t t h e b r i d g e ’ s c a p a c i t y w a s l i m i t e d b y t h e 3 5 m d e c k s p a n s a c r o s s t h e m a i n r i v e r c h a n n e l ,w h i c h p e r m i t t e d t h e u s e o f M L C 6 0 , o r a 6 0 - t o n v e h i c l e w i t h a s i n g l e - w a y c r o s s i n g . S u b s e q u e n t f i n d i n g so f t h e 1 9 8 5 b r i d g e c o n v e r s i o n f r o m r a i l t o r o a d w a y v e r i f i e d t h i s l o a d r a t i n g .A s t h e b r i d g e w a s r e p a i r e d , w o r k e r s c o m p l e t e d a m o r e t h o r o u g h v i s u a l i n s p e c t i o n , a n d u s e d h a n d t o o l st o i n v e s t i g a t e a n y a b n o r m a l i t i e s . U s i n g t h i s m e t h o d , c r e w s f o u n d a d d i t i o n a l m i n o r d e l a m i n a t i o n d a m a g e ,b u t n o t h i n g t o r e q u i r e a c h a n g e t o t h e i n i t i a l b r i d g ea s s e s s m e n t .C.20.4 Rapid RestorationC.20.4.1 Temporary StructureU s i n g a m o d u l a r p a n e l t r u s s b r i d g e s y s t e m , a p o n yt r u s s w a s b u i l t t o c r o s s t h e c o l l a p s e d r i v e r s p a n a n dt h r e e f l o o d p l a i n s p a n s . T h e r i v e r s p a n w a s a s i m p l ys u p p o r t e d d e c k t r u s s , a n d t h e f l o o d p l a i n s p a n s w e r ec o n t i n u o u s s p a n s w i t h i n t e r m e d i a t e b e n t s .B a i l e y B r i d g e - l i k e P a n e l T r u s s e s w e r e t h e s p e c i f i ct y p e o f t r u s s e s s e l e c t e d , a s s h o w n i n F i g u r e C - 8 6 .T h e s e w e r e m o d u l a r u n i t s t h a t c o u l d c a r r y u p t o M L C1 0 0 r a t i n g s f o r l e n g t h s u p t o 6 1 m . A d o u b l e w i d e m o d e lw a s c h o s e n w i t h a s i n g l e u n i t h e i g h t , a n d t h e c h o s e nM L C w a s a l i t t l e b i t g r e a t e r t h a n t h e M L C 6 0 r a t i n g . T ou s e t h i s s y s t e m , t w o i n t e r m e d i a t e p i e r s o n t h ef l o o d p l a i n n e e d e d t o b e r e p a i r e d , a s t h e y w e r e d a m a g e df r o m t h e e x p l o s i v e s . S e e F i g u r e C - 8 7 f o r t h e d e s i g nd e t a i l s . F u r t h e r m o r e , t h e y w e r e t o o l o w t o s u p p o r t t h et r u s s e s , s o t h e y h a d t o b e r a i s e d i n e l e v a t i o n . S t e e l w a sa d d e d f o r r e i n f o r c e m e n t a n d t h e c o n c r e t e m i x w a sc a t e r e d t o t h e h a r s h f r e e z e - t h a w c l i m a t e f o r d u r a b i l i t y .H i g h e a r l y s t r e n g t h w a s a r e q u i r e m e n t f o r t h ea c c e l e r a t e d c o n s t r u c t i o n . P r o p e r d e t a i l i n g w a s n e e d e dt o e n s u r e t h e r e w a s c o n t i n u i t y b e t w e e n t h e o l d s t o n ep i e r s a n d t h e n e w c o n c r e t e a d d i t i o n s .A t t h e s t a r t o f c o n s t r u c t i o n , t h e d a m a g e d s e c t i o n sw e r e c a r e f u l l y d i s m a n t l e d a s w o r k e r s w e r e s t i l l m i n d f u lo f t h e p o t e n t i a l f o r h i d d e n m i n e s . C o n c r e t e a n d s t e e lh a d t o b e r e m o v e d f r o m t h e e x i s t i n g i n t e r m e d i a t e p i e r s ,a n d t h i s w a s a c c o m p l i s h e d b y u s i n g c o n t r o l l e de x p l o s i v e s . U S m i l i t a r y e n g i n e e r s l e d t h e d e m o l i t i o n .O n c e t h e d a m a g e d s e c t i o n s w e r e r e m o v e d , c i v i l i a nc o n t r a c t o r s r e p a i r e d a n d r a i s e d t h e i n t e r m e d i a t e b e n t s o n t h e f l o o d p l a i n . T h e d a m a g e d m a s o n r y f r o m t h es t o n e w o r k w a s c h i p p e d o f f a n d r e i n f o r c e m e n t w a s a d d e d a n d g r o u t e d t o e n s u r e c o n t i n u i t y b e t w e e n t h e n e wa n d o l d s e c t i o n s . S i n c e c o n s t r u c t i o n t o o k p l a c e i n t h e w i n t e r , h e a t - i n s u l a t e d t e n t s w e r e u s e d t o p r o v i d es t a b l e c u r i n g c o n d i t i o n s . Q u a l i t y c o n t r o l w a s m e a s u r e d w i t h s l u m p t e s t s , N D E h a m m e r t e s t i n g , a n d c o n t r o lc u b e s .Figure C-86. Panel Truss System (with permission from ASCE, Mlakar & Ray 1997)Figure C-87. Pier Drawings (with permission from ASCE, Mlakar & Ray 1997)

201W h e n t h e c o n c r e t e r e a c h e d t h e m i n i m u m s t r e n g t h t h r e s h o l d , t h e p a n e l t r u s s e s w e r e s e t . T h i s t a s k w a sc o m p l e t e d b y U S a n d H u n g a r i a n m i l i t a r y e n g i n e e r s . A r e p r e s e n t a t i v e f r o m t h e p a n e l t r u s s m a n u f a c t u r e r l e dt h e i n s t a l l a t i o n a n d p r o v i d e d g u i d a n c e . T h e t r u s s e s w e r e a s s e m b l e d o n t h e r o a d , t h e n l a u n c h e d i n t o p l a c eu s i n g a r o l l e r s y s t e m , c r a n e , a n d f o r k l i f t . U s i n g j a c k s , t h e p a n e l s w e r e s e c u r e d t o t h e i r b e a r i n g s . T h i s p r o c e s st o o k a b o u t 1 0 d a y s t o c o m p l e t e , a n d t h e p r o g r e s s i o n o f w o r k i s s h o w n i n F i g u r e C - 8 8A l o a d t e s t w a s c o n d u c t e d o n c e t h e p a n e l s w e r e s e t . A n M L C 6 0 r a t e d v e h i c l e w a s d r i v e n a c r o s s t h eb r i d g e s l o w l y , a n d m i l i t a r y e n g i n e e r s v i s u a l l y i n s p e c t e d t h e b r i d g e a s i t t r a v e l e d a c r o s s . T h e y n o t e dl o c a t i o n s o f d e f l e c t i o n a n d o t h e r s i g n s o f d i s t r e s s . T h e s e r e s u l t s w e r e c o m p a r e d t o l o c a l s , w h o s a i d t h eb r i d g e p e r f o r m e d r o u g h l y t h e s a m e a s i t d i d b e f o r e t h e w a r d a m a g e .T h e b r i d g e w a s o p e n e d t o s u p p l y r o u t e s a s s o o n a s i t p a s s e d t h e l o a d t e s t i n g . P r o p e r s i g n a g e d e n o t e d t h eo n e - w a y t r a f f i c a n d s p e e d w a s m o n i t o r e d . W e e k l y v i s u a l i n s p e c t i o n s t o o k p l a c e t o e n s u r e t h e b r i d g e w a sp e r f o r m i n g a s i t s h o u l d .T h e p a n e l t r u s s d e s i g n e d w a s n o t d e s i g n e d t o l a s t f o r e v e r . O n c e w a r f a r e h a l t e d , t h e p a n e l s c o u l d b er e m o v e d a n d r e p l a c e d w i t h p e r m a n e n t t r u s s e s t h a t s u p p o r t t w o - w a y t r a f f i c .C.20.5 ChallengesW h e n U S c r e w s a r r i v e d t o r e p a i r t h e b r i d g e , i t w a s u n k n o w n i f t h e r e w e r e s t i l l m i n e s p r e s e n t a t t h e b r i d g e .T r o o p s h a d t o i n s p e c t t h e a r e a f o r e x p l o s i v e s , b u t t h i s w a s c h a l l e n g i n g a s t h e r e w a s a c o u p l e f e e t o f s n o wo n t h e g r o u n d a t t h e t i m e . W o r k e r s h a d t o b e e x t r e m e l y c a r e f u l a t t h e s i t e f o r t h e e n t i r e d u r a t i o n , a s t h e r ew a s a c o n s t a n t t h r e a t o f a t t a c k .S i n c e t h e b r i d g e w a s i n a n a c t i v e w a r s i t e , t h e o r i g i n a l b r i d g e p l a n s w e r e n o t a v a i l a b l e . M e a s u r e m e n t sh a d t o b e t a k e n i n t h e f i e l d , a n d a p r e l i m i n a r y e s t i m a t e o f t h e b r i d g e ’ s o r i g i n a l c a p a c i t y w a s m a d e f o l l o w i n gt h e m i l i t a r y c l a s s i f i c a t i o n p r o c e d u r e . T h i s p r o c e s s m i r r o r s t y p i c a l l o a d r a t i n g t e c h n i q u e s , b u t i t w a s g r e a t l yFigure C-88. Implementation Plan (with permission from ASCE, Mlakar & Ray 1997)

202 simplified for use by combat engineers. Allowable stress design was followed, but only the crews investigated the limiting elements on each bridge rather than analyzing the entire system. The final “result” was a standard military load class (MLC) that gave allowable weights based on tracked or wheeled vehicles. Another challenge was the panel truss load path. These bridges were not designed to sit on the superstructures of an existing bridge. Combat engineers had to make special calculations to ensure the proper load distribution and verify this decision would not decrease the bridge’s capacity. The design of the panel trusses included an indeterminate “X” frame, so computer modeling was used to analyze the various maximum live load cases. Load patterns were considered using allowable stress design and mimicked both military and civilian uses. The computer models confirmed the design would carry the MLC 60 that could be supported by the existing bridge structure. As a precautionary procedure to maintain the structural integrity of the bridge, traffic was restricted to alternating one-way flow, and regulated by military police and with a lower speed limit was set. C.20.6 Innovations and Lessons LearnedC.20.6.1 Implementation of Temporary Bailey BridgeThe use of portable modular prefabricated panel truss bridges that rest on the top of an existing bridgesuperstructure was not widespread before Sava River Bridge project. This paved the way for use of these systems in a simar manner and highlighted the need for further research in this area. Panel truss systems are a viable option for quick repairs, and should be considered for other situations, especially in war-time scenarios. C.20.6.2 Military Load Class RatingUsing the MLC when bridge plans are unknown is an alternative method to determining the capacity ofthe bridge, even in its damaged state. This procedure could be applied after natural disasters, as it is simpler than the traditional load-rating processes. C.20.6.3 Military Load Class RatingUsing the MLC when bridge plans are unknown is an alternative method to determining the capacity ofthe bridge, even in its damaged state. This procedure could be applied after natural disasters, as it is simpler than the traditional load-rating processes.

203 C.21 West Seattle Bridge 2020 [Immediate Action Inspection]Table C-21. West Seattle Bridge Case Study Name/Date West Seattle Bridge (2020) Location Washington, USA Event Type Immediate Action Inspection Bridge Name West Seattle High-Rise Bridge Scope/Costs Full Bridge Closure for 9+ months; $225 Million Planning Techniques/Tools Continued long-term monitoring, worst case scenario planning Event Response Immediate Structure Closure, detours Assessment Techniques/Tools Long term monitoring, visual inspection Rapid Restoration Type Temporary shoring, Carbon Fiber wrapping, bearing replacement, epoxy-crack injection Innovations • Long term monitoring• Non-Destructive Testing• Simultaneous temporary and permanent repair designC.21.1 IntroductionThe West Seattle High-Rise Bridge was Seattle’s busiest bridge, with over 100,000 vehicles travelingacross daily (Seattle Department of Transportation 2020). Built in 1984, The 2600ft bridge crosses the Duwamish River and connects West Seattle to Harbor Island (Newcomb 2020). The bridge had been closely monitored since 2013, when shear cracks were first noticed during a routine inspection on the post-tensioned box girders. However, subsequent inspections found the cracks to be rapidly growing. On March 23rd, 2020, there was a sudden growth in cracks, prompting an immediate structure closure. Extensive detours were put in place to reroute traffic, including restricting modes of transportation on the adjacent Spokane Street Low Bridge for commercial and public transportation use, and rerouting commuters to other nearby bridges. The decision on whether the bridge should be repaired or replaced was evaluated while emergency repairs were underway. The City of Seattle decided to repair the bridge and postpone replacement a few months after the structure was closed (Seattle Department of Transportation 2020). C.21.1.1 Event ResponseExtensive detours were established once the bridge was closed. The Seattle Department of Transportation(SDOT) coordinated with King County Metro to redesign public transportation routes and maintain the flow of commerce and travel. Local first responders such as the Seattle Police Department and Fire Department were also coordinated with to ensure that the closure did not have adverse effects on response times in the area (Seattle Department of Transportation 2020). As part of the detours, several local road improvements were also completed to help maintain traffic flow through the area. Remote adjustable traffic signals were installed at one intersection, which can be adjusted to accommodate changes in the detour routes or levels of traffic without having to send personnel on site. New bus lanes, pedestrian crossings, and modified travel lanes were also included in the project (Davis 2020c). The adjacent Spokane Street Low Bridge also underwent several improvements to ensure it would be able to handle the increase loading from heavy commercial vehicles and public transportation (Bergerson 2020b).

204 A task force was created, by utilizing pre-established unified response plans, which included the City of Seattle, the US Coast Guard, SDOT, and other local agencies. C.21.2 Emergency PlanningIn 2013, the first signs of distress were found on the West Seattle Bridge. Routine inspections scheduledfor every two years were increased to annually after the 2013 inspection. In 2019 the inspection frequency was increased to 4 a year, as the cracks first discovered were worsening at alarming rates. Then in 2020, the bridge was inspected each month until the closure (SDOT Blog 2020b). The structure was originally built for 6 lanes in total and was later retrofitted to include 7. Furthermore, an estimated 80% of the structure’s weight was attributed to dead load. These factors, compounded with increase vehicular weights over the years, caused the worsening of the cracks (Newcomb 2020). In 2014, the Seattle DOT installed long term remote monitoring equipment on the affected beams and girders of the West Seattle Bridge to keep track of the width of the existing cracks first noted in 2013. The long-term monitoring showed that the cracks began to rapidly grow over the later part of 2019 and into 2020, leading to the closure order. To aid in the structural assessment of the structure, SDOT hired a consultant to investigate the cracks. In February of 2020, the consultant recommended traffic be restricted on the bridge to only two lanes in each direction by the end of the calendar year. However, as the consultant refined their original analysis, they informed SDOT that the cracks were worse than first believed. From March 20-23rd, the bridge was visited daily, and on March 23rd, new cracks were found in areas previously denoted as “crack free”. The ever-increasing cracks led to the immediate closure (SDOT Blog 2020g). As more information was discovered about the worsening condition of the bridge, the task force began planning for a possible structure collapse. The growing shear cracks were of great concern, so three scenarios were planned: 1. Immediate Evacuation – indicates collapse is possible in a few days or hours2. One to Five Day Notice – for anticipated failure as opposed to immediate failure3. Controlled Demolitions – to maintain the safety of all parties involved, a date could be selected for thedemolitionAlong with the three scenarios described above, a “Fall Zone” was also outlined, and businesses and residences impacted by this region were notified of this possible danger. The designed “Fall Zone” included a buffer as well. Furthermore, in the event of a collapse by any of the three scenarios, access to Harbor Island could be cutoff altogether, so residences were told to prepare accordingly (Seattle Department of Transportation 2020). C.21.2.1 Crowdsourcing and Information GatheringSDOT used multiple communication platforms including AlertSeattle (push notifications), WirelessEmergency Alerts (texts), US Coast Guard Alerts (sirens from vessels and broadcasts to nearby ships), and Social Media Platforms to notify the public of event updates (such as Twitter, Facebook, and the City’s Website) (Seattle Department of Transportation 2020). C.21.3 AssessmentAfter the bridge was closed, further structural assessment was conducted. From these inspections, it wasfound that the bearing on Pier 18 were compressed and bulging. This indicated the bearing was restrained, which prevented the bridge from moving with changes in load. This in turn directs pressure on regions of the bridge that were not designed for such loads (Davis 2020a). New long-term monitoring equipment was installed on the bridge in July. This new system was installed to improve the monitoring of the cracks and included a camera system to provide real time visual

205 observation of the cracks. This new equipment found that the cracks did slow in growth once traffic was removed from the bridge, but still grew, although at reduced rates. The monitoring was vital to verify that the shoring and emergency repairs slowed the cracking, and provided more accurate indicators of further damage that may lead to a possible collapse. The sensors included with this equipment were movement sensors, which measure displacement in the horizontal and vertical direction, and crack monitors, which measure the width and slip of cracks. Cameras capture the growth of the cracks. Nondestructive testing of several post-tensioned cables was also conducted to determine if these elements were damaged as well. Over 100 non-destructive tests were conducted over the course of the project, including Ground Penetrating Radar (GPR) to identify areas of corrosion in the post-tension tendons (SDOT Blog 2020f) Impact Echo (IE), and Ultrasonic Pulse Velocity (UPV) to investigate the tendons and depth. The results from the GRP found corrosion was not a concern of the tendons (SDOT Blog 2020a). C.21.4 Rapid RestorationC.21.4.1 ContractingOnce the required repairs were decided upon, SDOT sent out a Request for Information (RFI) to procurea contractor. In this process, SDOT also waived typical competitive bid procedures to expedite the process. The contractors who submitted proposals for the project were evaluated based on their work with the city on previous projects and their proposal contents. (Davis 2020f). C.21.4.2 DesignAt the beginning of the project, it was unclear if the structure needed to be repaired or replaced. Whilethe more information was gathered on the bridge’s structural integrity, emergency repairs were scheduled and completed. It was determined the emergency repairs would center on releasing the compressed Pier 18 bearings. Shoring was designed to strengthen the structure and prevent the development of other cracks until these repairs could be made, (Davis 2020a). Meanwhile, a Technical Advisory Panel (TAP) was formed to determine the long-term repair or replacement of the structure. The panel consisted of experts in bridge engineering and construction, as well as those in geotechnical engineering and maritime industries. A community task force was also formed, as public input was also considered with the decision (Davis 2020d). As the decision was being made, a consultant was hired to design the replacement, as it was assumed the bridge would eventually be replaced, whether it was deemed the immediate solution or not. Other considerations for the solution included a tunnel instead of a bridge replacement (Bergerson 2020a). To help make the final decision, a cost-benefit analysis was used. This process looked at the benefits and drawbacks to either a total replacement or repair option. The criteria were heavily focused on the bridge’s current structural assessment, user impact, and cost (Davis 2020b). Ultimately, the Mayor of Seattle announced in November of 2020 that SDOT decided to progress the repair option as the long-term solution of the bridge’s condition. The structure would eventually be replaced, so replacement designs continued (SDOT Blog 2020d). C.21.4.3 Interim Repairs and MonitoringTo complete the stabilization of the structure with the Pier 18 bearing release, moveable platforms hadto be installed below the bridge to provide a space for work crews. These platforms used the original holes that were patched during construction. These holes were used to hold the “form travelers” used to build the

206 structure. The voids were reopened with core drills and other hydro demolition technical. All debris were captured in a vacuum system to prevent them from falling in the river below. Next, the severely cracked portions boxed girders of the bridge were wrapped in Carbon Fiber, and then external posttensioning was added to the box girders, stabilizing structure, and making it safer for workers to then shift repairs to the damaged bearings. The post tensioning was placed inside the box girders, so only the anchor points were visible from the underside of the bridge. After the first stages of stabilization was completed, crews were able to remove the damaged bearings. New rebar was added around the bearings, and new concrete joints were cast. Epoxy-injected cracks filled the array of cracks along the girders. Structural monitoring will continue until the permanent replacement is complete (SDOT Blog 2020d). C.21.4.4 Permanent StructureWhen the temporary repairs are completed, the focus of the project will shift to finalizing the permanentreplacement of the West Seattle Bridge. The necessary funding needs to be obtained. The design process will include public input and environmental review. C.21.5 ChallengesFunding was a major challenge for the project. SDOT considered federal, state, and local funding options,including grants, loans, and funding from the Washington State Legislature. Local funding sources were not popular (such as tolling), as the COVID-19 pandemic had already affected many local businesses and taxpayers. The ability to secure funding was a large motivator on the decision to repair versus replacing the structure in the near term. Repairs will allow more time to determine the best founding sources but may also increase the overall cost with higher future prices (Bergerson 2020c). The entire repair and replacement were estimated to be around $225 million. Ultimately, SDOT was able to secure an interfund loan to cover the initial emergency repairs costs, and then establish a Capital Improvement Program for the long-term solution (Davis 2020e). C.21.6 Innovations and Lessons LearnedC.21.6.1 Long-Term MonitoringThe West Seattle Bridge project heavily relied on long-term monitoring equipment to gather real-timeinformation on the bridge’s structural integrity. Crack detection, movement sensors, and cameras all played a vital role in determining if the bridge should be repaired or replaced. This equipment also increases safety of the workers making the emergency repairs, and the surrounding public. The long-term monitoring equipment and frequent inspections were the reason the structure was flagged for closure, likely preventing a collapse while in service. C.21.6.2 Detour Route ImprovementsAs the city of Seattle’s busiest bridge, it was important SDOT developed a thoughtful detour plan. Byworking with regional public transportation groups, the city was able to limit the disruption to the public while still maintaining a high-level of safety. Restricting traffic on the Spokane Street Low Bridge helped maintain a short route for first responders and commerce in the area, and relieved some of the added congestion from nearby roads. Intersection reconfiguration and lane improvements across the region also helped keep traffic flowing. Smart technologies traffic signals that can be update remotely gave SDOT the

207 ability to change traffic patterns as needed without having to send someone on site. All these improvements helped reduce the consequences of keeping the West Seattle Bridge closed for several months. C.21.6.3 Cost-Benefit Analysis to Determine Course of ActionBy using a cost-benefit analysis, the city was able to confidently make the decision to repair the bridgenow and delay a total replacement off to the future. Gathering information from the 100+ non-destructive tests, long-term monitoring results, and technical experts, the bridge’s structural integrity was then evaluated. Impacts to users and overall costs were also analyzed before the final decision was met. Completing this analysis while temporary repairs were being made helped save time, and provided the opportunity for a continued bridge investigation, as engineers discovered more information on the bridge’s capacity while making repairs. For the safety of the surrounding area itself, the temporary repairs had to take place, and it was logical to do so during the discussion on the bridge’s future. C.21.6.4 Communication with Key StakeholdersThe establishment of several task forces and the inclusion of community involvement early in the processhelped unite the city during this event. Since the West Seattle Bridge crosses the Duwamish Waterway, early involvement with the US Coast Guard was vital at understanding the unique requirements for ship traffic. Furthermore, updates through social media, push alerts systems such as AlertSeattle, and wireless emergency alerts were vital to keep the public informed of the constantly evolving event. Details about detour routes and areas impacted by the potential “Fall Zone” all helped keep the public informed, and to make it easier for people to plan accordingly, reducing overall disruption.

208 C.22 Franklin Ave 2015 [Other]Table C-22. Franklin Ave Case Study Name/Date Franklin Ave (2015) Location Minnesota, USA Event Type Other Bridge Name Franklin Avenue Bridge Scope/Costs Complete Bridge rehabilitation with new deck, cap beams, abutments, piers, arch ribs, and railings; total cost of $43.1 million Planning Techniques/Tools Erection sequencing, pre-Acceleration Bridge Construction (ABC) site set up, partial bridge closure to remove the railing Event Response N/A Assessment Techniques/Tools Visual Inspection Rapid Restoration Type ABC to replace the deck, pier caps, ornamental railings, and restore other concrete components using precast concrete. Innovations • Using precast to replicate ornamental historic features• Prioritizing multi-modal useC.22.1 IntroductionThe historic Franklin Ave Bridge located in Minneapolis, MN was in disrepair and needed to berehabilitated. A popular route for multi-modal traffic, the rehabilitation not only replaced deteriorated structural elements, but updated the structure for multi-modal use. Only closed sixteen weeks, the rehabilitation used ABC, as the arch design complicated staged construction, and temporary supports would dramatically increase costs and extend the project to two construction seasons. The bridge did have to close completely, but it was the best procedure to stay within schedule limits (Sivakumar 2017). C.22.2 Emergency PlanningC.22.2.1 Crowdsourcing and Information GatheringPublic input was included in the rehabilitation design phase. The community wanted multi-modaltransportation to be included with the design to accommodate pedestrians, bikes, and vehicles. The design team led open discusses with the community to ensure their desires were heard and needs addressed. The design ultimately settled on two thru lanes with a median separated bike and pedestrian paths (Sivakumar and Konda 2017). Furthermore, a previous 1970 rehabilitation removed many of the historic components of the bridge. The public wanted to restore the historic details in the new rehabilitation, which included the railing, lights, columns, and pier overlooks (Sivakumar and Konda 2017). When scheduling the construction timeline for the bridge, the public wanted a limited closure period so residents could enjoy the bridge for part of the summer months. Using ABC made this dream a reality, as the bridge was only closed for sixteen weeks (Sivakumar and Konda 2017).

209 C.22.3 AssessmentThe Franklin Avenue Bridge went under a deep comprehensive investigation to examine theperformance, durability, and historical importance in 2007. This test was recommended by the National Park Service Preservation Brief which implies that an inspection should be done to examine the durability of the concrete. This comprehensive exam included detailed surveys, delamination surveys, reinforcing bar cover surveys with the use of ground-penetrating radar, corrosion potential, concrete resistivity, and many other tests. After all these tests were conducted, it was determined that the bridge had widespread concrete deterioration it its abutments, piers, and arch ribs. The main cause of the deterioration was due to chloride corrosion. The concrete was exposed to a chloride-laden water that occurred due to deicing salts leaking through the expansion joints (Johnston 2017). The Franklin Avenue Bridge was built in 1923 and was the world’s longest arch bridge of its time. It was listed on the National Register in 1978 of historic bridges and voted a Minneapolis landmark in 1985. The bridge’s design consisted of a 5-span open spandrel concrete arch bridge. The arch ribs were reinforced with steel Melan trusses (Sivakumar and Konda 2017). Visual inspections revealed severe concrete deterioration, leaking expansion joints, and exposed reinforcement (Sivakumar and Konda 2017). C.22.4 Rapid RestorationC.22.4.1 Permanent StructureTo prepare for the ABC process, the deck panels, cap beams, and ornamental railings were all precastand brought to the site via barge. The proposed designed decreased the number of expansion joints from 15 to 6 to reduce the chances of deterioration. The deck panels were fabricated at the KNA Bohemian Flats yard, making 4-5 panels a day for a total of 350 panels. The panels were cured with steam and then pressure washed before transport. The panel production started a year before the actual ABC work due to the large quantity of panels. The 43 cap beams were manufactured in Elk River, MN, and all 163 ornamental railing panels were built in New Ulm, MN (Sivakumar and Konda 2017). Before construction began, the utility rack and falsework were installed to prepare for the rehabilitation. Then, with a partial bridge closure, the 1970 railing was cut and removed from the bridge. Then, ABC was ready to begin (Sivakumar and Konda 2017). The bridge was cut in the transverse direction using a saw, and pieces were removed and placed on a barge. The pier walls were removed, and then the new pier overhang was cast in place due to its curved geometry. With the overhangs curing, the cap beams were removed and then replaced, lowering them to the bridge with cranes. Grout was used to connect the cap beams to the columns. By day 19 of construction, the deck panels were ready to be set. These were slid into place using polytetrafluoroethylene (PTFE) and connected using Ultra High-Performance Concrete (UHPC) joints (Sivakumar and Konda 2017). A polyester polymer overlay was laid on top of the joints for added protection (Sivakumar 2017). Next, the ornamental railing was placed, then pilasters were formed between each railing section after they were secured to the bridge. To cover the deck, pre-mixed polymer concrete (PPC) was spread. Once cured, the bridge was then opened to traffic (Sivakumar and Konda 2017). C.22.5 ChallengesThe UHPC joints did not fit together perfectly, as there were rebar conflicts with the closures. Thiscommon problem with UHPC joints stems from a lack of established project tolerances. Having a comprehensive QAQC plan to spot errors with congested joints, streamlines the installation process (Sivakumar and Konda 2017).

210 Around the same time of the concrete manufacturing of the numerous precast components, the Vikings Football stadium in Minneapolis was also under construction. This led to a concrete shortage and significantly higher concrete prices. To try and reduce costs, most of the precast components were shipped to the site via barge, and some were even fabricated close to the site to reduce transportation costs. Furthermore, some of the remnant piers were salvaged, reusing concrete (Johnson et al. 2017). C.22.6 Innovations and Lessons LearnedC.22.6.1 Importance of Pre-ABC PlanningThe team learned how valuable pre-ABC planning was to finish the project on time. Setting up thenecessary equipment, making site preparations, and modeling construction sequencing are all ways the team can be prepared for construction and to reduce the likelihood of issues during construction (Sivakumar and Konda 2017). C.22.6.2 Awareness of Historic Bridge Properties and ComponentsDuring the restoration, it was imperative that the construction team was familiar with the historicconstruction. Since historic concrete does not sound nor feel the same has new concrete, this increases the likelihood for structural damage as well as increase repair costs (Accelerated Bridge Construction University Transportation Center, n.d.b.).

211 C.23 I-84 Bridges 2013 [Other]Table C-23. I-84 Bridges Case Study Name/Date I-84 Bridges (2013)Location New York, USA Event Type Other Bridge Name I-84 Bridges over Dingle Ridge RoadScope/Costs Total Replacement of 2 I-84 Bridges over 2 weekends and total cost $7.83 million Planning Techniques/Tools Permitting attainment and building temporary shoring for new structure to be built Event Response Maintaining NYSDOT website to keep the public informed Assessment Techniques/Tools Inspection Reports and visual inspection for existing structure, SRTT and OBSI for new structure Rapid Restoration Type ABC using hydraulic jacks to slide new bridges constructed alongside the existing bridges into place Innovations • Sliding bridges into place with Push Grippers• Using approach slabs as temporary spans before fill couldbe placed• Building new abutment around existing one to limit trafficdisruption.C.23.1 IntroductionThe twin I-84 Bridges over Dingle Ridge Road had deteriorated and needed to be replaced. Located insoutheast New York, these bridges had an ADT of 75,000, and served a vital role for commerce in the area. The state of New York decided to use Accelerated Bridge Construction (ABC) for the project to reduce traffic disruption, impact to the surrounding watershed, and to reduce construction costs. By using this technique, they were able to save approximately $2.7 million. These savings accounted for more than 20% of the original cost of the bridge without Accelerated Bridge Construction (Bhajandas et al. 2014). The new bridges used a Northeast Extreme Tee (NEXT) beams with precast approach slabs and an Ultra High-Performance Concrete (UHPC) closure pour on top of new bents. New York was satisfied with the result and began investigating what other bridges it could replace using this method (Sivakumar 2017). C.23.1.1 Event ResponseClear communication to the public was key throughout the process. Notice of closures and delays helpedreduce the traffic during the time of the closure by about 40%. Updates were issued from the NYSDOT website. A detailed timeline was initially released and included updated photos and current traffic conditions (Bhajandas et al. 2014). C.23.2 Emergency PlanningC.23.2.1 Crowdsourcing and Information GatheringThe state of New York knew it needed to replace the twin I-84 bridges, but it did not know the bestmethod of the replacement. As decisions regarding the construction procedure were underway, the team

212i n v e s t i g a t e d t h e p e r m i t s a n d o t h e r r e q u i r e m e n t s f o r t h e p r o j e c t . D u e t o i t s l o c a t i o n i n t h e N e w Y o r k C i t yw a t e r s h e d , e x t r a p r e c a u t i o n s w e r e m a n d a t e d . M o r e o v e r , a s i t e s u r v e y r e v e a l e d t h e b r i d g e s h a d a n e l e v a t i o nd i f f e r e n c e o f 1 5 ’ b e t w e e n t h e m , c o m p l i c a t i n g t h e p r o p o s e d t e m p o r a r y b r i d g e m e t h o d t o c a r r y t h e t r a f f i c o fo n e b r i d g e d u r i n g c o n s t r u c t i o n . T h e u s e o f t r a d i t i o n a l c o n s t r u c t i o n m e t h o d s w i t h i t s t e m p o r a r y s t r u c t u r ea n d c r o s s o v e r s y s t e m w o u l d c o s t a b o u t $ 2 m i l l i o n m o r e o n t o p o f t h e p r i c e f o r t h e n e w b r i d g e s a n d t a k et w o y e a r s . H o w e v e r , w i t h A B C , t h e p r o j e c t w o u l d o n l y a f f e c t t r a f f i c f o r t w o w e e k e n d s u s i n g a s l i d e - i na p p r o a c h , a n d g r e a t l y r e d u c e t h e i m p a c t o n t h e w a t e r s h e d . T h u s , t h e t e a m d e c i d e d t o u s e A B C f o r t h i sp r o j e c t ( B h a j a n d a s e t a l . 2 0 1 4 ) .C.23.3 AssessmentT h e o r i g i n a l t w i n b r i d g e s w e r e b u i l t i n 1 9 6 7 a n d w e r e1 4 0 f e e t l o n g l e n g t h a n d 3 3 . 3 f e e t w i d e . T h e e a s t b o u n db r i d g e h a d a s u f f i c i e n c y r a t i n g o f 6 2 . 0 ; t h e w e s t b o u n db r i d g e h a d a r a t i n g o f 6 0 . 2 . I n a d d i t i o n , t h e b r i d g e s h a do t h e r s t r u c t u r a l d e f i c i e n c i e s t h a t n e e d e d t o b ea d d r e s s e d , a s r e v e a l e d b y i n s p e c t i o n r e p o r t s .T e m p o r a r y s t e e l s u p p o r t s w e r e p u t i n p l a c e o n b o t hb r i d g e s t o p r e v e n t w e b c r i p p l i n g . L e a k i n g j o i n t ss e v e r e l y d a m a g e d t h e b r i d g e , a n d t h e d e c k w e a r i n gs u r f a c e h a d w o r n a s p h a l t . L a s t l y , a p p r o x i m a t e l y 2 5 % o ft h e s t e e l g i r d e r s w e r e s i g n i f i c a n t l y r u s t e d , a s n o t e d b y av i s u a l i n s p e c t i o n ( B h a j a n d a s e t a l . 2 0 1 4 ) . A n i m a g e f r o m d e m o l i t i o n i s s h o w n i n F i g u r e C - 8 9 .O n c e t h e c o n s t r u c t i o n o f t h e n e w b r i d g e s w a s c o m p l e t e , t h e y w e r e r e - e v a l u a t e d . T h e r o a d w a y q u a l i t yw a s t e s t e d u s i n g t h e o n b o a r d s o u n d i n t e n s i t y ( O B S I ) t e c h n i q u e p r e s c r i b e d i n A A S H T O . T h e t e s t c o n d u c t e dw a s a s t a n d a r d r e f e r e n c e t e s t t i r e ( S R T T ) . T o t e s t f o r r o a d w a y s m o o t h n e s s , a h i g h - s p e e d i n e r t i a l p r o f i l e rw a s u s e d . T h e n e w b r i d g e s u r f a c e s w e r e d e e m e d a n i m p r o v e m e n t f r o m t h e e x i s t i n g b r i d g e s ( B h a j a n d a s e ta l . 2 0 1 4 ) .C.23.4 Rapid RestorationC.23.4.1 Permanent StructureT h e f i r s t s t a g e o f t h e p r o j e c t w a s t h e P r e - A B C p e r i o d .D u r i n g t h i s s t a g e , t h e n e w a b u t m e n t s w e r e b u i l t o n t h ed r i l l e d s h a f t s , c o n c u r r e n t l y w i t h t h e s u p e r s t r u c t u r e b u i l ta d j a c e n t t o t h e b r i d g e o n t e m p o r a r y p i l e s . T h e s e c o n ds t a g e w a s t h e A B C p e r i o d , w h e r e o n e d i r e c t i o n o f t r a f f i cw a s c l o s e d t o d e m o l i s h t h e e x i s t i n g b r i d g e a n d t o s l i d et h e n e w s p a n s i n t o p l a c e . T h e l a s t s t a g e w a s t h e p o s t -A B C p e r i o d , w h e r e f l o w a b l e f i l l w a s a d d e d u n d e r t h ea p p r o a c h s l a b s , t h e t e m p o r a r y s u p p o r t s w e r e r e m o v e d ,t h e w i n g w a l l s w e r e a d d e d , a n d t h e f i n a l a p p r o a c h e sw e r e c o m p l e t e d ( B h a j a n d a s e t a l . 2 0 1 4 ) .Figure C-90. Elevation of Abutment Design (Bhanjandas et al. 2014)Figure C-89. Bridge Demolition (Bhajandas et al. 2014)Figure C-91. Beam Installation (Bhajandas etal. 2014)

213W h i l e t h e o r i g i n a l s t r u c t u r e w a s s t i l l i n o p e r a t i o n , t h e p i l e s f o r t h e n e w b r i d g e w e r e d r i l l e d o n t h e o u t s i d eo f t h e e x i s t i n g f o o t p r i n t . T h i s m i n i m i z e d t r a f f i c i m p a c t a n d p r o v i d e d a s t a b l e f o u n d a t i o n t o p l a c e t h es u b s t r u c t u r e . A t o t a l o f e i g h t s h a f t s w e r e d r i l l e d , t w o o n e a c h a b u t m e n t . T h e c a s t i n g s w e r e 6 f e e t i n d i a m e t e r .T h e s u b s t r u c t u r e c o n s i s t e d o f a s a d d l e b e n t a b u t m e n t , w h i c h c o m p r i s e d o f a c a p b e a m s u p p o r t e d b y t h ed r i l l e d s h a f t s a n d s l i d i n g s h o e s u n d e r t h e d i a p h r a g m . F o r t h e n e w s p a n s ’ c o n s t r u c t i o n , t h e s e c o m p o n e n t sw e r e e r e c t e d o n s t e e l t e m p o r a r y p i l e s e q u i p p e d w i t h s l i d e t r a c k s , w h i c h w e r e l o c a t e d a t e a c h b e n t( B h a j a n d a s e t a l . 2 0 1 4 ) .T h e c a p b e a m h a d p o l y t e t r a f l u o r e t h y l e n e ( P T F E ) s l i d i n g b e a r i n g p a d s t o s u p p o r t t h e e n d d i a p h r a g m . T h ec a p b e a m w a s p l a c e d o n t o p o f t h e d r i l l e d s h a f t s f o l l o w e d b y t h e d i a p h r a g m , a s s h o w n i n F i g u r e C - 9 0 .T h e s e w e r e o r i g i n a l l y s e t o n t h e t e m p o r a r y b e n t s a n dw e r e l a t e r s l i d i n t o p l a c e . O n c e i n p l a c e , t h e N E X Tb e a m s w e r e l o w e r e d t o s i t o n t h e c a p b e a m s , a s s h o w ni n F i g u r e C - 9 1 . T h e d e c k r e i n f o r c e m e n t w a s e p o x yc o a t e d o n t h e b o t t o m a n d s t a i n l e s s s t e e l o n t h e t o p .U H P C w i t h s t e e l f i b e r s w a s u s e d t o c l o s e t h e j o i n t s , d u et o t h e “ B u y A m e r i c a ” c l a u s e i n t h e c o n t r a c t , w h i c hl i m i t e d t h e m a t e r i a l t h a t c o u l d b e p u r c h a s e d , a s s h o w ni n F i g u r e C - 9 2 ( B h a j a n d a s e t a l . 2 0 1 4 ) .W i t h t h e j o i n t s s e a l e d , t h e d e c k w a s b l a s t c l e a n e d t op r e p t h e s u r f a c e f o r t h e p r i m e r a n d r u b b e rw a t e r p r o o f i n g l a y e r s ( B h a j a n d a s e t a l . 2 0 1 4 ) . T h eb r i d g e w a s t h e n r e a d y f o r t h e l a t e r a l s l i d e , a s s h o w n i nF i g u r e C - 9 3 .F o r t h e A B C s t a g e o f t h e p r o j e c t , a p r e q u a l i f i e dc o n t r a c t o r m a n a g e d t h e o p e r a t i o n s . T h e c o n t r a c t o r su s e d t h e i r e x p e r t i s e t o s e l e c t t h e b e s t m e t h o d f o r m o v i n gt h e s t r u c t u r e , w h e t h e r i t i s w i t h S e l f P r o p e l l e d M o d u l a rT r a n s p o r t e r s ( S P M T s ) , r o l l e r s , o r j a c k s . I n t h i s i n s t a n c e ,t h e P u s h G r i p p e r w a s s e l e c t e d . O n e w a s p l a c e d a t e a c hd i a p h r a g m t o p u s h t h e b r i d g e i n t o p l a c e u s i n g h y d r a u l i c s . T h e b r i d g e s l i d a c r o s s P T F E b o n d e d t oe l a s t o m e r i c p a d s , w h i c h h a d a f r i c t i o n c o e f f i c i e n t o f o n l y a p p r o x i m a t e l y 8 % ( B h a j a n d a s e t a l . 2 0 1 4 ) .W h e n i t w a s t i m e t o s l i d e t h e w e s t b o u n d b r i d g e , t h e e x i s t i n g b r i d g e w a s d e m o l i s h e d a s s o o n a s t h e r o a dw a s c l o s e d . O v e r t w e n t y h o u r s , t h e b r i d g e w a s d e m o l i s h e d , d e b r i s r e m o v e d , a n d t h e n e w s t r u c t u r e w a s s l i di n t o p l a c e . F o r t h e e a s t b o u n d b r i d g e , t h i s p r o c e s s w a s a c c o m p l i s h e d i n s e v e n h o u r s , a s t h e c o n t r a c t o r w a sm o r e e x p e r i e n c e d w i t h t h e s e c o n d s l i d e ( D ' A m i c o 2 0 1 3 ) . T h e s l i d e m o v e d b o t h t h e b r i d g e a n d t h ea p p r o a c h e s t o r e d u c e c l o s u r e t i m e . W i t h t h i s d e s i g n , t h e a p p r o a c h e s a c t e d l i k e e n d s p a n s , a n d t h e n o n c e i np l a c e , f i l l w a s p o u r e d i n u n d e r n e a t h t h e m t o c r e a t e a s i n g l e s p a n d e s i g n . T h e a p p r o a c h e s w e r e d e s i g n e d t oc a r r y t r a f f i c l o a d s , a s t h e y w o u l d t e m p o r a r i l y d o s o u n t i l t h e f i l l w a s a b l e t o b e a d d e d ( B h a j a n d a s e t a l .2 0 1 4 ) .Figure C-92. UHPC Joint (Bhanjandas et al.2014) Figure C-93. Waterproofing Spray (Bhajandas et al. 2014)

214D u r i n g t h e w e s t b o u n d ( f i r s t ) s l i d e , o n e o f t h e P u s h G r i p p e r sa d v a n c e d q u i c k e r t h a n t h e o t h e r , c a u s i n g t h e b r i d g e t o f i s h t a i la n d b i n d . T h i s w a s a t t r i b u t e d t o h e a v y r a i n s a t t h e t i m e a n d p o o rc o m m u n i c a t i o n b e t w e e n w o r k e r s . T h i s e r r o r w a s l a t e r c o r r e c t e df o r t h e e a s t b o u n d s l i d e , w h i c h w a s a c c o m p l i s h e d w i t h o u ti n c i d e n t ( B h a j a n d a s e t a l . 2 0 1 4 ) . S e e F i g u r e C - 9 4 f o r a v i e w o ft h e P u s h G r i p p e r a n d F i g u r e C - 9 5 f o r a n i m a g e o f t h e s l i d e f r o mt h e g r o u n d .T h e n e w b r i d g e d e s i g n r a i s e d t h e u n d e r p a s s t w o f e e t f o r e x t r ac l e a r a n c e o f v e h i c l e s o n D i n g l e R i d g e R o a d . T o a c c o m m o d a t et h i s , t h e a p p r o a c h s l a b s d e s i g n i n c l u d e d a f a i r l y s t e e p a n g l e , b u tt h i s a l l o w e d f o r a s p h a l t p l a c e m e n t s i m u l t a n e o u s l y , s p e c i f i c a l l yi n t h e b u i l t - u p a r e a s b e f o r e t h e a p p r o a c h . W i t h t h e a s p h a l t l a i d ,t h e b r i d g e w a s s t r i p e d a n d t h e n w a s r e o p e n e d t o t r a f f i c( B h a j a n d a s e t a l . 2 0 1 4 ) .D i n g l e R i d g e R o a d c l o s e d r i g h t b e f o r e t h e s l i d e a n d r e m a i n e dc l o s e d f o r a f e w d a y s a f t e r e a c h b r i d g e m o v e ( B h a j a n d a s e t a l .2 0 1 4 ) .C.23.5 ChallengesT h e u n d e r p a s s r o a d , D i n g l e R i d g e R o a d , h a d a s t e e pg r a d e o f a b o u t 1 6 % . F u r t h e r m o r e , t h e e a s t b o u n d a n dw e s t b o u n d I - 8 4 l a n e s w e r e a t d i f f e r e n t h e i g h t s d u e t ot h e s t e e p t o p o g r a p h y . B e c a u s e o f t h i s , t w o p l a t f o r m s ,e a c h a t t h e i r o w n h e i g h t , h a d t o b e c o n s t r u c t e d t o h o l dt h e n e w s p a n s d u r i n g t h e A B C p h a s e ( D ' A m i c o 2 0 1 3 ) .A t o u g h p e r m i t t i n g p r o c e s s b e c a u s e o f t h e n e a r b yw a t e r s h e d w a s a l s o l e n g t h y , a n d o t h e r r e q u i r e m e n t ss u c h a s t h e “ B u y A m e r i c a ” c l a u s e i n t h e c o n t r a c tr e q u i r e d m a t e r i a l s t o b e A m e r i c a n m a d e . T h e s eo b s t a c l e s w e r e e a s i l y o v e r c o m e , b u t m o r e t i m e s h o u l db e s e t a s i d e b e f o r e t h e c o n s t r u c t i o n b e g i n s t o e n s u r e a l lt h e d e t a i l s a r e i r o n e d o u t t o p r e v e n t d e l a y s .C.23.6 Innovations and Lessons LearnedC.23.6.1 Keeping the Public Informed of ClosuresL o o k i n g b a c k a t t h e f i n i s h e d p r o j e c t , t h e N e w Y o r kD e p a r t m e n t o f T r a n s p o r t a t i o n f o u n d t h e t w o - w e e k e n d c l o s u r e sw e r e a n a d e q u a t e a m o u n t o f t i m e t o c o m p l e t e t h e l a t e r a l s l i d eo p e r a t i o n s a n d t h e p u b l i c w a s p r o v i d e d s u f f i c i e n t n o t i c e , s o t h e yd i d n o t o b s e r v e s i g n i f i c a n t t r a f f i c d i s r u p t i o n . P u b l i c o u t r e a c hw a s p a r t i a l l y t o t h a n k , a n d t h e f r e q u e n t u p d a t e s t o t h e w e b s i t ew a s a l s o a c c r e d i t e d ( B h a j a n d a s e t a l . 2 0 1 4 ) . F o r a n e a r l yc o m p l e t e d p r o j e c t i m a g e , s e e F i g u r e C - 9 6 .Figure C-94. Push Gripper Installation (Bhajandas et al. 2014) Figure C-95. Slide in of Bridge (Bhajandas et al. 2014) Figure C-96. Aerial View of Construction Site with Nearly Completed Bridges (Bhajandas et al.2014)

215C.23.6.2 Requiring Key Personnel to Remain On-SiteI t w a s f o u n d t h a t k e y d e c i s i o n m a k e r s , s u c h a s e n g i n e e r s a n d c o n t r a c t o r s s h o u l d b e p r e s e n t o n s i t e t oa d d r e s s a n y p r o b l e m s t h a t a r o s e ( B h a j a n d a s e t a l . 2 0 1 4 ) .C.23.6.3 Complete all Contracts Before ConstructionC o n t r a c t s s h o u l d b e t h o r o u g h a n d c o m p l e t e b e f o r ec o n s t r u c t i o n b e g i n s t o e n s u r e t h e j o b d e s c r i p t i o n i s d e t a i l e d a n da c c u r a t e . A n y d i s c r e p a n c i e s c a n t a k e v a l u a b l e t i m e t o s o r t o u t ,a n d a n y m i s s i n g i n f o r m a t i o n w i l l o n l y b e m a g n i f i e d d u e t o t h ec o m p r e s s e d t i m e l i n e ( B h a j a n d a s e t a l . 2 0 1 4 ) .C.23.6.4 Slide-In Placement ProceduresW h e n i t c a m e t o s l i d i n g t h e b r i d g e s i n t o p l a c e , a c o n s e r v a t i v ev a l u e f o r t h e c o e f f i c i e n t o f f r i c t i o n s h o u l d b e u s e d t o a c c o u n tf o r u n f o r e s e e a b l e e v e n t s , l i k e p o o r w e a t h e r c o n d i t i o n s , t h a t w i l li m p a c t t h e c o e f f i c i e n t ( B h a j a n d a s e t a l . 2 0 1 4 ) . S e e F i g u r e C - 9 7f o r a n i m a g e o f t h e s l i d e . I t i s e x t r e m e l y i m p o r t a n t t o m o n i t o r t h e s l i d e . S e v e r a lw o r k e r s s h o u l d b e o n l y a s s i g n e d t h e t a s k o f m o n i t o r i n g t h ep r e s s u r e r e a d i n g s a n d m e a s u r e m e n t s t o e n s u r e t h e b r i d g e i ss h i f t i n g u n i f o r m l y t o p r e v e n t b i n d i n g . N e g l i g e n c e c o u l d c a u s ed a m a g e t o t h e c o m p o n e n t s a n d d e c r e a s e t h e o v e r a l l s t r u c t u r a li n t e g r i t y ( B h a j a n d a s e t a l . 2 0 1 4 ) .Figure C-97. Sliding of Approach into Place (Bhajandas et al. 2014)

216C.24 Keg Creek Bridge Replacement 2011 [Other]Table C-24. Keg Creek Bridge Replacement Case Study Name/ Date Keg Creek Bridge Replacement (2011)L ocation Iowa, USAEvent Type OtherBridge Name Keg Creek BridgeScope/ Costs Demo and Repair of Bridge in 16 days (2 days late), total cost $ 2.67 millionPlanning Techniques/ Tools Built a fabrication yard adjacent to the bridge to manufacture precast components before demolition to reduce traffic impactEvent Response N/ AAssessment Techniques/ Tools Inspection ReportsRapid Restoration Type ABC with prefabricated componentsInnovations • Prefabricated rolled steel girders with concrete deck +railing• Fabrication lot on-site• Culverts to divert water and create a dry working area• Post-tensing and UHPC combination to prevent joints fromcrackingC.24.1 IntroductionT h i s s t u d y f o c u s e s o n t h e K e g C r e e k B r i d g eR e p l a c e m e n t p r o j e c t c o n d u c t e d b y t h e I o w a D O T . T h eo r i g i n a l K e g C r e e k B r i d g e w a s b u i l t i n 1 9 5 3 w i t h an a r r o w r o a d w a y o f o n l y 2 8 ’ . T h e c o n t i n u o u s c o n c r e t e3 - s p a n b r i d g e w a s c l a s s i f i e d a s s t r u c t u r a l l y d e f i c i e n t( E v a n s 2 0 1 7 ) .T h e I o w a D O T w e i g h e d t h e p r o s a n d c o n s o f u s i n gA c c e l e r a t e d B r i d g e C o n s t r u c t i o n ( A B C ) t o r e p l a c e t h ee x i s t i n g b r i d g e . U s i n g t r a d i t i o n a l c o n s t r u c t i o n m e t h o d s ,t h e p r o j e c t w a s e s t i m a t e d t o h a v e a 6 - m o n t h c l o s u r ew i t h a 1 4 - m i l e d e t o u r . H o w e v e r , w i t h t h e u s e o f A B C ,t h e p r o j e c t w o u l d o n l y t a k e a b o u t 1 4 d a y s – s i g n i f i c a n t l yr e d u c i n g t h e i m p a c t t o t h e p u b l i c .T h e I o w a D O T d e c i d e d t o p u r s u e t h e A B C p r o c e s sf o r t h i s 3 - s p a n b r i d g e w i t h j o i n t l e s s c o n s t r u c t i o n a n dp r e - d e c k e d s t e e l b e a m s . T h e p r o j e c t c o s t $ 2 . 6 7 m i l l i o na n d i n c l u d e d a $ 2 2 k / d a y i n c e n t i v e / d i s i n c e n t i v e w i t h t h e1 4 - d a y s c h e d u l e . T h e b r i d g e w a s c o m p l e t e d i n 1 6 d a y s u s i n g p r e f a b r i c a t e d c o m p o n e n t s b u i l t a d j a c e n t t ot h e b r i d g e , a n d t h e I o w a D O T w a s o v e r a l l s a t i s f i e d w i t h t h e o u t c o m e ( S i v a k u m a r 2 0 1 7 ) . S e e F i g u r e C - 9 8f o r a n i m a g e o f t h e e x i s t i n g s t r u c t u r e .Figure C-98. Existing Bridge (Used with permission © Iowa Department of Transportation, Evans 2017)

217 C.24.1.1 Event ResponseThe Keg Creek Bridge Replacement project received funds from Highways for Life (HFL) for $600,000and the Transportation Research Board’s Strategic Highway Research Program 2 (SHRP2) funds of $250,000 which greatly reduced the overall cost to the Iowa DOT (Sivakumar 2017). Keg Creek was chosen as a part of a study to investigate the viability of ABC, and more specifically, with a precast modular structure and precast approaches. Moreover, the 3-span system was chosen to better represent other bridges in the area, providing the opportunity for this bridge to serve as a demonstration for the state of Iowa. C.24.2 Emergency PlanningC.24.2.1 Crowdsourcing and Information GatheringPast Iowa bridge case studies were used as examples to determine the best options for the project. Theuse of ABC was relatively new to Iowa, but other rapid repair technologies were not. The agency decided to pick and choose rapid methods from other projects to serve as a model for this case. Typically, the Iowa DOT used concrete overlays with precast panel bridges. But for this project, an overlay would add weeks to the duration. The Iowa DOT had experience with Ultra High-Performance Concrete (UHPC) with other projects to create an impenetrable and stronger joint. However, they did not have experience using preassembled rolled steel girders but likened some characteristic to other projects with the more typical assembled on-site girders. This helped prepare the Iowa DOT for the Keg Creek Bridge replacement. This project was the first one that Iowa DOT conducted with the use of steel girder/concrete deck modules jointed on site with UHPC (Littleton & Mallela 2013). C.24.3 AssessmentThe original Keg Creek Bridge was built in 1953 with a narrow roadway of only 28’. The continuousconcrete 3-span bridge had a sufficiency rating of 33 (structurally deficient), so the Iowa DOT knew it was time to replace the structure (Evans 2017). C.24.4 Rapid RestorationC.24.4.1 ProcurementAll precast units for the bridge were cast at the on-site fabrication lot adjacent to the bridge, as shown inFigure C-100. This saved a significant amount of time and money for the project. High Performance Concrete (HPC) with a strength of 5,000 psi and mild epoxy coated reinforcement was used for the precast. The fabrication lot was divided up by the different bridge components, such as columns, approach slabs, deck, and abutments. However, due to convenience, the pier cap was cast in the dry stream channel before demolition. To fabricate the girders, the steel was first manufactured at a plant, then brought to the jobsite. Temporary wooden bents were constructed at the on-site fabrication lot, and the steel girders were set into place. Then, forms were used to create the composite steel/concrete girders. Similar to cast-in-place techniques, the concrete was supported by the girders during curing (Evans 2017).

218C.24.4.2 Permanent StructureB e f o r e t h e e x i s t i n g b r i d g e w a s d e m o l i s h e d , d r i l l e ds h a f t s f o r t h e n e w b r i d g e w e r e b o r e d a n d f i l l e d w i t hc o n c r e t e a n d r e i n f o r c e m e n t ( I o w a D e p a r t m e n t o fT r a n s p o r t a t i o n n . d . ) . C o n c u r r e n t l y , t h e n e c e s s a r y c u l v e r ti m p l e m e n t a t i o n f o r t h e s t r e a m d i v e r s i o n w a s b u i l t t oc r e a t e a d r y w o r k s p a c e f o r c r a n e s a n d o t h e r e q u i p m e n t ,a s s h o w n i n F i g u r e C - 9 9 ( E v a n s 2 0 1 7 ) .F r o m h e r e , t h e e x i s t i n g b r i d g e w a s c l o s e d t o t r a f f i c ,a n d t h e d e m o l i t i o n b e g a n . I t t o o k t w o h y d r a u l i cb r e a k e r s o n l y 1 d a y t o c o m p l e t e w i t h t h e h e l p o f aw r e c k i n g b a l l . T h e n e w l y b o r e d d r i l l e d s h a f t s a n d p i e rc a p s w e r e p r o t e c t e d t o e n s u r e t h e y w e r e n o t d a m a g e db y f a l l i n g d e b r i s ( E v a n s 2 0 1 7 ) . N e x t , t h e a b u t m e n t p i l e sw e r e d r i v e n a n d g r o u t e d , a l l o w i n g f o r t h e p l a c e m e n t o ft h e p r e c a s t a b u t m e n t c o m p o n e n t s . T h e i n t e r m e d i a t ep r e c a s t c o l u m n s a n d p i e r c a p s w e r e a l s o s e t a t t h i s t i m e ,a s s h o w n i n F i g u r e C - 1 0 1 . T h e c o l u m n s w e r e p l a c e d o na s p o n g e r u b b e r b e d t o h o l d t h e g r o u t i n p l a c e . T h ea b u t m e n t s u s e d a s e m i - i n t e g r a l d e s i g n w h i c h p r o v i d e dr o o m f o r e x p a n s i o n o r c o n t r a c t i o n o f t h e s u p e r s t r u c t u r e .I t a l s o w a s e a s y t o s e t t h e s u p e r s t r u c t u r e i n t o p l a c e , a n dt h u s w o r k e d s e a m l e s s l y f o r r a p i d c o n s t r u c t i o n Figure C-100. Aerial View of Fabrication Lot (Used with permission © Iowa Department of Transportation, Evans 2017)Figure C-99. Aerial View of Construction Site with Culverts (Used with permission © Iowa Department of Transportation, Evans 2017)Figure C-101. Pier Cap Placement (Used with permission © Iowa Department of Transportation, Evans 2017)

219t e c h n i q u e s ( I o w a D e p a r t m e n t o f T r a n s p o r t a t i o n a n d S i v a k u m a r 2 0 1 7 ) . S e l f - c o n s o l i d a t i n g c o n c r e t e w a su s e d i n t h e a b u t m e n t a s s e m b l y t o f i n i s h o f f t h e p i l e c a p s . A n c h o r s a n d b e a r i n g s w e r e i n s t a l l e d o n b o t h t h ea b u t m e n t s a n d t h e b e n t c a p s . F r o m h e r e , t h e p r e c a s t w i n g w a l l s w e r e i n s t a l l e d ( E v a n s 2 0 1 7 ) .W i t h t h e a b u t m e n t s i n p l a c e , t h e p r e c a s t g i r d e r s w e r e s e t w i t h t w o c r a n e s . U H P C w a s u s e d t o c l o s e t h et r a n s v e r s e d e c k j o i n t s b e t w e e n s p a n s , a s t h i s a l l o w e d f o r f u l l m o m e n t t r a n s f e r a n d d i d n o t r e q u i r e t r a n s v e r s ep o s t - t e n s i o n i n g . T h e c l o s u r e s w e r e o n l y 6 ” w i d e , c r e a t i n g l o w p e r m e a b i l i t y ( S i v a k u m a r 2 0 1 7 ) . F r o m h e r e ,t h e w i n g w a l l j o i n t s w e r e s e a l e d w i t h s e l f - c o n s o l i d a t i n g c o n c r e t e a n d U H P C w a s u s e d t o c l o s e t h el o n g i t u d i n a l j o i n t s b e t w e e n g i r d e r s ( E v a n s 2 0 1 7 ) .W i t h t h e b r i d g e c o m p l e t e d , t h e p r e c a s t a p p r o a c h p a n e l s w e r e s e t , a n d j o i n t s s e a l e d w i t h s e l f - c o n s o l i d a t i n gc o n c r e t e . T h e s u p e r s t r u c t u r e w a s t h e n p o s t - t e n s i o n e d , w i t h t e n d o n s p l a c e d t h r o u g h p r e - d r i l l e d h a n g e r s a n dh o l e s o n t h e e x t e r i o r o f t h e s t e e l g i r d e r s a b o v e t h e i n t e r m e d i a t e b e n t s . T h e d e c k a n d a p p r o a c h e s w e r e g r o u n dd o w n f o r a s m o o t h r i d i n g s u r f a c e , a n d t h e n t h e b r i d g e w a s o p e n e d t o t r a f f i c . R i p r a p a n d o t h e r s c o u rm e a s u r e s w e r e i n s t a l l e d a f t e r t h e b r i d g e w a s r e o p e n e d ( I o w a D e p a r t m e n t o f T r a n s p o r t a t i o n n . d . ) .C.24.5 ChallengesT h e u s e o f h a i r p i n j o i n t b a r s m a d e i t d i f f i c u l t t o a s s e m b l e t h ep r e c a s t p i e c e s , a s t h e c u r v e d b a r s w e r e h a r d t o a l i g n , a s s h o w ni n F i g u r e C - 1 0 2 . T h e c o n t r a c t o r r e c o m m e n d e d f u t u r e u s e o fs t r a i g h t b a r e n d s f o r U H P C b o n d i n g t o a v o i d f i t p r o b l e m s a n dm i s a l i g n m e n t s . F u r t h e r m o r e , t h e j o i n t s w e r e o f t e n c o n g e s t e d ,a n d a n y a d j u s t m e n t t o t h e h a i r p i n s t o a l l o w f o r a p r o p e r f i t r a nt h e r i s k o f d a m a g i n g t h e e p o x y o n t h e b a r s . T h e U H P C j o i n t sa r e c r i t i c a l , a s t h e y a r e w h a t h o l d t h e b r i d g e t o g e t h e r . A n yc r a c k s c a n l e a d t o f r e e z e - a n d - t h a w d a m a g e , s o i t i s i m p e r a t i v et h e r e i s c l e a r c o m m u n i c a t i o n b e t w e e n t h e m a n u f a c t u r e r a n dw o r k e r s . T h e U H P C j o i n t a t t h e a b u t m e n t w a s d i f f i c u l t t o f o r m ,s o t h e U H P C l e a k e d u n d e r t h e b a c k w a l l , w h i c h c r e a t e d a m e s s .F i g u r e C - 1 0 3 s h o w s t h e p o u r i n g o f a U H P C j o i n t .C.24.6 Innovations and Lessons LearnedC.24.6.1 Stream Channel AccessH a v i n g a c c e s s t o t h e s t r e a m c h a n n e l w a s o n e o f t h e b e s td e c i s i o n s m a d e f o r t h i s p r o j e c t . C u l v e r t s w e r e c o n s t r u c t e db e f o r e d e m o l i t i o n s t o a l l o w f o r e a s i e r a c c e s s . T h i s p e r m i t t e dt h e u s e o f t h e c h a n n e l f o r e q u i p m e n t , a s p o t f o r p r e c a s t i n g t h ep i e r c a p s , a n d a s s e m b l i n g t h e c o m p o n e n t s ( E v a n s 2 0 1 7 ) .C.24.6.2 On-Site Fabrication LotT h e f a b r i c a t i o n l o t n e x t t o t h e b r i d g e a l s o s t r e a m l i n e d t h ep r o c e s s a n d r e d u c e d o v e r a l l c o s t s . S p e c i a l p e r m i t s w e r e n o t n e e d e d f o r l a r g e p i e c e s , a s t h e r e w a s n o t r a v e lr e q u i r e d o n p u b l i c r o a d s . H o w e v e r , t h e c o n t r a c t o r w a s n o t a f a n o f t h e p r e c a s t a p p r o a c h e s , a s t h e s u b g r a d eh a d t o b e a t t h e p r o p e r e l e v a t i o n s f o r a s m o o t h f i n i s h . T h i s p r e c i s i o n t a k e s t i m e , a n d t h e y w o u l d r e c o m m e n du s i n g t y p i c a l c a s t - i n - p l a c e a p p r o a c h e s f o r f u t u r e A B C p r o j e c t s ( E v a n s 2 0 1 7 ) .Figure C-102. Hairpin Fitting Challenge (Used with permission © Iowa Department of Transportation, Evans 2017) Figure C-103. UHPC Poured into Place (Used with permission © Iowa Department of Transportation, Evans 2017)

220C.24.6.3 UHPC JointsT h e u s e o f U H P C o v e r a p i e r c a p h a d n o t y e t b e e ni n v e s t i g a t e d b e f o r e t h i s p r o j e c t . T h e h i g h l o a d s c o u l dc r e a t e c r a c k s a n d d e b o n d i n g f r o m t h e s t e e l , w h i c hc o u l d l a t e r t u r n i n t o l e a k i n g j o i n t s . T e s t s w e r ec o n d u c t e d t o d e t e r m i n e i f U H P C c o u l d b e u s e d i n t h i sc a p a c i t y . T h e r e s u l t s f o u n d t h a t a d d i n g p o s t - t e n s i o n i n gr o d s w o u l d l i m i t t h e l i k e l i h o o d o f t h e j o i n t f r o md e b o n d i n g a n d c r a c k i n g , s o t h i s w a s a d d e d t o t h ed e s i g n , a s s h o w n i n F i g u r e C - 1 0 4 . D u r i n g i n s t a l l a t i o n ,a l l t h e r o d s w e r e s t r e s s e d s i m u l t a n e o u s l y f o r a n e v e nl o a d d i s t r i b u t i o n ( E v a n s 2 0 1 7 ) .T h e a b u n d a n c e o f f o r m s s h o u l d b e c o n s i d e r e d d u r i n g t h e p r o c u r e m e n t p h a s e . M a s s p r o d u c t i o n o f t h ef o r m s f r o m a c a r p e n t e r s h o u l d b e p u r c h a s e d t o r e d u c e t h e t i m e r e q u i r e d f o r w o r k e r s t o a s s e m b l e f o r m s o ns i t e ( E v a n s 2 0 1 7 ) .C.24.6.4 InspectionI n s p e c t o r s s h o u l d b e f a m i l i a r w i t h A B C p r o c e s s , a n d i f n e e d e d , c o m p l e t e t r a i n i n g o n h o w t o i n s p e c t A B Cp r o j e c t s . T h e s i m u l t a n e o u s c o n s t r u c t i o n a n d r a p i d p r o g r e s s m a y b e o v e r w h e l m i n g a n d / o r a l t e r t h e t y p i c a ls t e p s o f w o r k , c o n f u s i n g t h e i n s p e c t o r . T h i s s h o u l d b e c o n s i d e r e d w i t h f u t u r e p r o j e c t s ( E v a n s 2 0 1 7 ) .T h e i n s p e c t o r s s h o u l d b e o n s i t e f o r m a n y p r o j e c t m i l e s t o n e s , i n c l u d i n g t h e c o l u m n p l a c e m e n t o n t h eb e d , a n d i t s s u b s e q u e n t g r o u t i n g . P o o r l y f o r m e d f o o t i n g s c o u l d l e a d t o s t r u c t u r e c o l l a p s e ( E v a n s 2 0 1 7 ) .C.24.6.5 Length of ConstructionT h e p r o j e c t t o o k 2 d a y s l o n g e r t h a n e x p e c t e d . W e a t h e r , f l o o d i n g , a n d a l i t a n y o f o t h e r f a c t o r s c o u l dc o n t r i b u t e m o r e t o s u c h d e l a y s i n t h e f u t u r e . I t w a s r e c o m m e n d e d t o a d d a “ g r a c e p e r i o d ” t o t h e c o n t r a c t t oa c c o u n t f o r t h e s e u n k n o w n s , e s p e c i a l l y w i t h s u c h a n a c c e l e r a t e d s c h e d u l e . T h i s w i l l r e d u c e t h e p r e s s u r e so f f t h e c o n t r a c t o r a n d p r o v i d e a b u i l t - i n b u f f e r ( E v a n s 2 0 1 7 ) .Figure C-104. Post-Tensioning over Pier Cap (Used with permission © Iowa Department of Transportation, Evans 2017)

221C.25 Salt Lake City Olympics ABC 2002 [Other]Table C-25. Salt Lake City Olympics ABCCase Study Name/ Date Salt L ake City Olympics ABC (2002)L ocation Utah, USAEvent Type OtherBridge Name One bridge is not selected for this report0Scope/ Costs Considered ABC for all Bridge Projects (hundreds of bridges)Planning Techniques/ Tools Pre-event workshops to develop ABC standards and detailsEvent Response N/ AAssessment Techniques/ Tools N/ ARapid Restoration Type Accelerated Bridge ConstructionInnovations • Precast components• Self-Propelled Modular Transporters (SPMT) specificationsto limit cracking and dynamic loading• Guidelines to regularly inform management• Though not directly related to a specific emergency event,the processes developed are relevant to large scale eventsthat require the use of ABC. Serves as a “ mock” scenario.C.25.1 IntroductionT o p r e p a r e f o r t h e 2 0 0 2 O l y m p i c s , U t a h D O T ( U D O T ) u s e dA c c e l e r a t e d B r i d g e C o n s t r u c t i o n ( A B C ) t o p r e p a r e i t si n f r a s t r u c t u r e f o r t h e i n f l u x o f v i s i t o r s a s w e l l a s t o s h o w c a s et h e s t a t e - o f - t h e - a r t t e c h n o l o g y a t t h a t t i m e . T h i s p u s h f o r A B Cw a s a s u c c e s s a n d b y 2 0 1 0 , A B C b e c a m e s t a n d a r d p r a c t i c e f o ra l l c a s e s w h e r e i t w a s d e e m e d p r a c t i c a l a n d c o s t e f f e c t i v e .E x a m p l e s o f A B C p r o j e c t s a r e s h o w n i n F i g u r e C - 1 0 5 a n dF i g u r e C - 1 0 6 .C.25.2 Emergency PlanningC.25.2.1 Crowdsourcing and Information GatheringT h e m a s s i m p l e m e n t a t i o n o f A B C w a s r e l a t i v e l y n e w f o r t h eU D O T s o a f t e r e a c h c o m p l e t e d p r o j e c t , t h e y d i s t r i b u t e dq u e s t i o n n a i r e s t o t h e p u b l i c f o r f e e d b a c k . I n m o s t c a s e s ,r e s p o n d e n t s w e r e n e a r l y e q u a l l y s p l i t b e t w e e n s a t i s f i e d , n o ts a t i s f i e d , a n d i n d i f f e r e n t . A n a l y s i s o f t h e s e r e s p o n s e sd e t e r m i n e d t h a t t h o s e r e s p o n d i n g n e g a t i v e l y w e r e n o t s a t i s f i e dw i t h t h e p r o j e c t o v e r a l l , n o t s p e c i f i c a l l y t h e u s e o f A B C .F o r o n e p r o j e c t , a L i k e r t 7 - p o i n t p o l l i n g s y s t e m w a s u s e d , a n dr e s u l t s w e r e c o m p a r e d t o a n o n - A B C p r o j e c t . O v e r 9 7 % s a w t h eA B C p r o j e c t a s a s u c c e s s a n d r a t e d i t 3 o r h i g h e r . U D O T u t i l i z e dFigure C-105. Installation of Precast Element (Culmo 2011)Figure C-106. Precast Slab Placement (Culmo 2011)

222t h e s e r e s u l t s d u r i n g U t a h ’ s l e g i s l a t i v e s e s s i o n t o s e c u r e m o r e f u n d s . A s a r e s u l t o f t h i s d e m o n s t r a t e d s u c c e s s ,U t a h h a s c o n t i n u e d t o s e e i n c r e a s e s i n t r a n s p o r t a t i o n f u n d i n g i n r e c e n t y e a r s d e s p i t e t i m e s o f f i s c a l r e s t r a i n t .C.25.3 AssessmentI n f o r m a t i o n o n s t r u c t u r a l a s s e s s m e n t w a s n o t f o u n d . I n m o s t c a s e s b r i d g e s t h a t w e r e r e p l a c e d w e r er e p l a c e d t o a d d c a p a c i t y r a t h e r t h a n d u e t o s t r u c t u r a l c o n s i d e r a t i o n s .C.25.4 Rapid RestorationC.25.4.1 DesignW i t h m a n y o f t h e A B C p r o j e c t s f o r U D O T , d e s i g ns t a n d a r d s , s p e c i f i c a t i o n s , a n d d e t a i l s w e r e a l li m p l e m e n t e d t o s p e e d u p t h e o v e r a l l p r o c e s s . P r i o r t o t h em a s s i m p l e m e n t a t i o n , U D O T h o s t e d s e v e r a l w o r k s h o p st o d e v e l o p t h e s e s t a n d a r d s . G r o u p s s u c h a s t h e U t a hA s s o c i a t i o n o f G e n e r a l C o n t r a c t o r s ( A G C ) , A m e r i c a nC o u n c i l o f E n g i n e e r i n g C o m p a n i e s ( A C E C ) , a n d P r e c a s tP r e s t r e s s e d C o n c r e t e I n s t i t u t e ( P C I ) w e r e p r e s e n t t os h a r e t h e i r i n p u t a n d t o c r e a t e a c o h e s i v e p l a n .C.25.4.2 Permanent StructureD e p e n d i n g o n t h e s i t e , U D O T u s e s l i g h t w e i g h tc o n c r e t e f o r i t s A B C p r o j e c t s , a s t h e s t a t e ’ s s o i l c o n t a i n ss i g n i f i c a n t d e p o s i t s o f B o n n e v i l l e c l a y , w h i c h p u t ss t r u c t u r e s a t a r i s k f o r s e t t l e m e n t . T h e l i g h t w e i g h tc o n c r e t e r e d u c e s t h i s r i s k , w h i c h h e l p s w i t h s e i s m i cd e s i g n b u t a l s o m a k e s i t e a s i e r t o u s e S e l f P r o p e l l e dM o d u l a r T r a n s p o r t e r s ( S P M T s ) , o r o t h e r s i m i l a rp r o c e s s e s ( F i g u r e C - 1 0 7 ) , t o s l i d e t h e b r i d g e c o m p o n e n t si n t o p l a c e . H o w e v e r , U t a h d o e s n o t h a v e a n yr e q u i r e m e n t s t o u s e o v e r l a y s o n l i g h t w e i g h t c o n c r e t e , s oi n o t h e r s t a t e s t h i s m a y a d d a d d i t i o n a l t i m e t o t h e o v e r a l lp r o j e c t .U t a h a l s o u s e s c a s t - i n - p l a c e c l o s u r e p o u r s , e s p e c i a l l ya r o u n d a b u t m e n t s . T h e s u p e r s t r u c t u r e c a n b e b u i l t o u t o fp r e c a s t g i r d e r s o r s l a b s , a n d U t a h h a s s e v e r a l p u b l i s h e ds t a n d a r d s f o r p r e c a s t d e c k p a n e l s t h a t a c t l i k e a o n e - w a ys l a b . T h e s e s l a b s a r e s u p p o r t e d b y b e a m s w i t hp r e s t r e s s i n g o r m i l d r e i n f o r c e m e n t . F o r b e n t s a n d i n t e r m e d i a t e s u p p o r t s , o p e n f r a m e b e n t s a r e p o p u l a r b u tc a n b e c h a l l e n g i n g t o e r e c t ( F i g u r e C - 1 0 8 ) .P r e f a b r i c a t i o n o f t h e s e c o m p o n e n t s o f f s i t e , a n d t h e n t r a n s p o r t i n g t h e m i n t o b e a s s e m b l e d o n s i t e s a v e s t i m ea n d m o n e y . T o m e e t s e i s m i c r e q u i r e m e n t s , U t a h i m p l e m e n t e d a g r o u t e d s p l i c e c o u p l e r t o a c h i e v e t h e s a m es e i s m i c b e n e f i t s a s a c a s t - i n - p l a c e c o n c r e t e . I n e s s e n c e , t h i s d e s i g n a l l o w s t h e b a r s p r o t r u d i n g f r o m o n ee l e m e n t t o “ p l u g i n ” t o t h e v o i d s i n a n o t h e r . T h e n t h e c o n n e c t i o n i s g r o u t e d w i t h h i g h s t r e n g t h g r o u t . T h i sFigure C-107. Bridge Slide-In Installation (Culmo 2011)Figure C-109. Open Frame Bent Design (Culmo 2011)Figure C-108. Integral Abutment Design (Culmo 2011)

223d e s i g n i s s i m i l a r t o a l a p p e d s p l i c e a n d c a n b e a p p l i e d i n t h e s a m e f a s h i o n t o o t h e r c o m p o n e n t s s u c h a sw i n g w a l l s , a b u t m e n t s , a n d f o o t i n g s .F o r a b u t m e n t s , U D O T d e v e l o p e d s t a n d a r d s f o r a n i n t e g r a l a b u t m e n t d e s i g n ( F i g u r e C - 1 0 9 ) . T h i s m e t h o du s e s v e r t i c a l s h e a r k e y s w i t h g r o u t , a n d w h e n c o m b i n e d w i t h t r a n s v e r s e r e i n f o r c e m e n t t o d i s t r i b u t e t h e l o a d ,t h e s y s t e m c a n w i t h s t a n d t h e i n t e r n a l p i l e a n d o t h e r g e o t e c h n i c a l f o r c e s .C.25.5 ChallengesT h e u s e o f p r e c a s t c o m p o n e n t s r e q u i r e s s e v e r a l j o i n t s a c r o s s t h e l e n g t h o f t h e b r i d g e , o f t e n r e s u l t i n g i nj o i n t s t h a t r e d u c e t h e r i d e q u a l i t y . D i a m o n d g r i n d i n g r e d u c e s t h e b u m p s b u t i s n o t a s s m o o t h a t y p i c a l c a s t -i n - p l a c e d e c k b e c a u s e i t r e m o v e s t h e f i n e a g g r e g a t e a n d e x p o s e s t h e c o a r s e a g g r e g a t e . I t a l s o r e n d e r s t h es u r f a c e m o r e p r o n e t o f r e e z e - a n d - t h a w .A n o t h e r i s s u e w i t h p r e f a b r i c a t e d c o m p o n e n t s o c c u r sw i t h t h e r a i l i n g . A n e x t e r i o r g i r d e r m a y e n d u p c a r r y i n ga g r e a t e r l o a d w i t h t h e a d d i t i o n o f t h e p r e c a s t p a r a p e tr a i l i n g t h a n i f i t w e r e c a s t - i n - p l a c e . T h i s e x t r a d e a d l o a dm u s t b e c o n s i d e r e d i n t h e o r i g i n a l d e s i g n . U n i f o r mt o r q u e s a p p l i e d t o a l l b o l t s a t t a c h i n g t h e r a i l i n g t o t h eg i r d e r s c a n a l s o h e l p d i s t r i b u t e t h e l o a d t o t h e i n t e r i o rg i r d e r s a s w e l l .W h e n u s i n g S P M T s t o m o v e s u p e r s t r u c t u r ec o m p o n e n t s i n t o p l a c e ( F i g u r e C - 1 1 0 ) , i n t e r n a l s t r e s s e s( o f t e n u n a c c o u n t e d f o r ) i n d u c e d b y t h e d y n a m i c m o t i o nm a y a d v e r s e l y i m p a c t t h e s t r u c t u r e . T o t e s t t h e i m p a c to f t h i s m o v e m e n t , U t a h S t a t e U n i v e r s i t y a t t a c h e d s t r a i ng a u g e s t o d i f f e r e n t s u p e r s t r u c t u r e s d u r i n g t h e S P M Tp r o c e s s a t t h e b e g i n n i n g o f t h e 2 0 0 2 A B C p u s h . T h e yc o n c l u d e d t h a t a n a d d i t i o n a l d y n a m i c l o a d a l l o w a n c e o fa p p r o x i m a t e l y 1 5 % o f t h e d e a d l o a d s h o u l d b e i n c l u d e dd u r i n g d e s i g n t o p r e v e n t a n y m a j o r i s s u e s . T h e y a l s of o u n d t h a t t h a t t o r s i o n a l e f f e c t s d u r i n g t r a n s p o r t w e r en e g l i g i b l e , b u t o n l y i f t h e b r i d g e w a s w r a p p e d p r o p e r l ya n d m o v e m e n t s w e r e m a i n t a i n e d w i t h i n s p e c i f i e dt o l e r a n c e s . F u r t h e r m o r e , t h e u s e o f S M P T s o f t e ne q u a t e s t o l a r g e o v e r h a n g s o f s p a n s d u r i n g t h e m o v e .U t a h f o u n d t h a t i t s o r i g i n a l r u l e o f s u p p o r t a t t h i r dp o i n t s l e d t o d a m a g e d p a r a p e t s a n d c r a c k s i n t h e d e c k .T o r e d u c e c r a c k i n g , o v e r h a n g s w e r e l i m i t e d t o o n l y2 0 % o f t h e o v e r a l l l e n g t h .O f t e n , h i g h s t r e n g t h c l o s u r e p o u r s a r e s p e c i f i e d f o rA B C . T h i s i s r e q u i r e d t o m e e t t h e e a r l y - s t r e n g t hr e q u i r e m e n t s f o r a s p e e d y c o n s t r u c t i o n , b u t t h e s e m i x e so f t e n l e a d t o c r a c k i n g d u e t o d r y i n g s h r i n k a g e ( F i g u r eC - 1 1 1 ) . S p e c i f y i n g l o w e r s t r e n g t h c o n c r e t e c a n h e l p s o l v e t h i s p r o b l e m a n d r e d u c e c r a c k i n g p o t e n t i a l .H o w e v e r , D O T s m u s t b e s u r e t o c h e c k t h e i r r e q u i r e m e n t s f o r c l o s u r e s b e c a u s e , f o r t r a d i t i o n a l c a s t - i n - p l a c ep r o j e c t s , t h e c o n c r e t e s t r e n g t h m a y b e s i g n i f i c a n t l y h i g h e r a n d o f t e n s p e c i f i c a t i o n s d o n o t c h a n g e b e t w e e nc a s t - i n - p l a c e a n d p r e c a s t .Figure C-111. Closure Pour Crack (Culmo 2011) Figure C-110. SMPT on I-80 Bridge Replacement (Culmo 2011)

224 C.25.6 Innovations and Lessons LearnedC.25.6.1 Organizing Management for ABCAs Utah gained experience and expertise with ABC, they developed a flow chart showing the steps takenthat led to their successes. UDOT found that regular communication with both upper management and politicians on ABC projects not only helped secure funds for further ABC expansion in the next legislative round, but also gain support from the public. Middle management should also be informed, and an open dialogue between the contractors, engineers, and management should always be implemented. The speed of construction often leads to more questions up front and during construction, thus delays can be prevented if the key players shift to an “on-call” role. Honest communication and explaining the successes and challenges provide the foundation for transparency. C.25.6.2 Stakeholder Buy-InThere are several advantages of ABC that are important to share with stakeholders. First, it greatlyreduces traffic impacts and delays and is safer for both workers and the public, as most construction takes places away from travel lanes. Furthermore, ABC may cost more up front, but in the long run, it generally saves a considerable amount of money. Lastly, higher quality bridges can be built, as the precast components can be manufactured in a controlled environment, away from harsh weather conditions and other uncontrollable factors.

225C.26 State Route 30 & Bessemer Ave 2015 [Other]Table C-26. State Route 30 & Bessemer Case Study Name/ Date State Route 30 & Bessemer (2015)L ocation Pennsylvania, USAEvent Type OtherBridge Name State Route 30 & Bessemer AveScope/ Costs $ 2.3 millionPlanning Techniques/ Tools Pro Team Meetings and Constructability Meetings, BIM to sequence construction events and check component fitEvent Response N/ AAssessment Techniques/ Tools L idar scan to generate as-builts since limited bridge knowledge was availableRapid Restoration Type ABC with precast steel composite slabs, new abutment cap, and precast approachesInnovations • L ightweight concrete to reduce component weights• Revit to sequence construction eventsC.26.1 IntroductionT h e S t a t e R o u t e 3 0 & B e s s e m e r A v e b r i d g e i n P e n n s y l v a n i a w a s a u n i q u e c h a l l e n g e t o e n g i n e e r s . T h eb r i d g e h a d l i m i t e d a s - b u i l t i n f o r m a t i o n , a n d t h e l a c k o f a v i a b l e d e t o u r r o u t e m e a n t t h e c o n s t r u c t i o n n e e d e dt o b e c o m p l e t e d r a p i d l y t o r e d u c e t r a f f i c i m p a c t . M o r e o v e r , t h e b r i d g e h a d b o t h a s k e w a n d a c u r v e da l i g n m e n t . T h e p r o j e c t u s e d A c c e l e r a t e d B r i d g e C o n s t r u c t i o n ( A B C ) t o r e m o v e a n d r e p l a c e p a r t o f t h ea b u t m e n t s a n d b u i l d a n e w a p p r o a c h s l a b t o i n c r e a s e t h e c l e a r a n c e u n d e r t h e b r i d g e b y t h r e e f e e t a n d f i v ei n c h e s . T h e e n t i r e p r o j e c t w a s p u t i n p l a c e i n j u s t 5 7 h o u r s , f o r a t o t a l c o s t o f $ 2 . 3 m i l l i o n ( P e n n s y l v a n i aD e p a r t m e n t o f T r a n s p o r t a t i o n 2 0 1 6 , S i v a k u m a r 2 0 1 7 ) .C.26.2 Emergency PlanningN o i n f o r m a t i o n r e g a r d i n g e v e n t p l a n n i n g w a s f o u n d .C.26.3 AssessmentT h e o r i g i n a l b r i d g e w a s b u i l t i n 1 9 3 0 a n d u s e d a T -B e a m S u p e r s t r u c t u r e d e s i g n . T h e b r i d g e h a d a l o wc l e a r a n c e o f 1 3 ’ - 9 ” w h i c h w a s d e e m e d t o o l o w f o rl a r g e r v e h i c l e s , a s s h o w n i n F i g u r e C - 1 1 2 . M o r e o v e r ,t h e s u p e r s t r u c t u r e w a s a c t i v e l y c r u m b l i n g , a n d d e b r i sw a s f a l l i n g t h r o u g h a h o l e i n t h e d e c k , m a k i n g a s p e e d yr e p a i r i m p e r a t i v e ( R u z z i e t a l . n . d . ) .Figure C-112. Original Bridge (Ruzzi et al. n.d.)

226S i n c e t h e r e w a s l i m i t e d i n f o r m a t i o n a v a i l a b l e a b o u t t h e b r i d g e , a l i d a r s u r v e y o f t h e e n t i r e s t r u c t u r e w a sc o m p l e t e d . T h i s g a v e e n g i n e e r s a b e t t e r u n d e r s t a n d i n go f h e e x i s t i n g s t r u c t u r e , b u t a l s o p r o v i d e d c r i t i c a li n f o r m a t i o n s u c h a s d i m e n s i o n s ( S i v a k u m a r 2 0 1 7 ) .T h e L i d a r s c a n s w e r e p r o c e s s e d t o d e v e l o p 3 D a s -b u i l t s f o r t h e b r i d g e , a n d w e r e u s e d t o d e s i g n t h e n e wa b u t m e n t c a p , s u p e r s t r u c t u r e , a n d a p p r o a c h e s ( R u z z ie t a l . n . d . ) . B u i l d i n g i n f o r m a t i o n m o d e l i n g ( B I M ) w a su s e d t o c o n v e r t t h e l i d a r d a t a i n t o a 3 D m o d e l a s s h o w ni n F i g u r e C - 1 1 3 .O n c e a d e s i g n w a s g e n e r a t e d , t h e b r i d g e w a sv i r t u a l l y a s s e m b l e d t o c h e c k f o r c o m p o n e n t f i t , a n do v e r a l l c o n s t r u c t i o n s e q u e n c e . T h e 3 D r e n d e r i n g s w e r eg i v e n t o t h e c o n t r a c t o r t o a s s i s t w i t h c o n s t r u c t i o n( R u z z i e t a l . n . d . ) .C.26.4 Rapid RestorationC.26.4.1 Permanent StructureT h e c o n s t r u c t i o n w a s s e t t o t a k e p l a c e o v e r aw e e k e n d t o m i n i m i z e t r a f f i c d i s r u p t i o n . A s s o o n a s t h eb r i d g e c l o s e d a t 9 p m o n F r i d a y , d e m o l i t i o n b e g a n . T h ea b u t m e n t w a s s a w - c u t a l o n g t h e b a c k s i d e t o r e m o v e t h ed e t e r i o r a t e d p o r t i o n s , a n d t h e n t h e s u p e r s t r u c t u r e w a sd e m o l i s h e d , i n c l u d i n g t h e a p p r o a c h e s . W i t h t h e d e b r i sc l e a r e d , t h e n e w ( a n d t a l l e r ) a b u t m e n t c a p s w e r e l i f t e di n t o p l a c e . T h e a b u t m e n t c a p s w e r e s e c u r e d w i t hd o w e l s , a n d s h i m s w e r e p l a c e d t o r e a c h t h e c o r r e c t s e a te l e v a t i o n s , a s s h o w n i n F i g u r e C - 1 1 4 . T h e g a p s c r e a t e d b y t h e s h i m s w e r e f i l l e d w i t h r a p i d s e t g r o u t v i ap o r t s . T h e n , c r a n e s w e r e u s e d t o l i f t t h e p r e c a s t m o d u l a rs l a b s i n t o p l a c e , a s s h o w n i n F i g u r e C - 1 1 5 . T h e s e s l a b sw e r e m a d e u p o f s t e e l g i r d e r s w i t h a c o m p o s i t el i g h t w e i g h t p r e c a s t c o n c r e t e d e c k s l a b . A t t h e s a m et i m e , t h e p r e c a s t a p p r o a c h s l a b s w e r e a l s o i n s t a l l e d .T h e s e s l a b s h a d a s t e e p e r a n g l e t h a n i n t h e o r i g i n a lb r i d g e t o a c c o m m o d a t e t h e h i g h e r b r i d g e s p a n .L i g h t w e i g h t c o n c r e t e w a s u s e d f o r t h e n e w b r i d g e t or e d u c e w e i g h t s r e q u i r e d b y t h e c r a n e s . U l t r a h i g h -p e r f o r m a n c e c o n c r e t e ( U H P C ) w a s u s e d f o r t h e c l o s u r ep o u r s a s s h o w n i n F i g u r e C - 1 1 6 . O n c e c u r e d , t h e b r i d g ew a s o p e n e d t o t r a f f i c ( R u z z i e t a l . n . d . ) .I n t h e d a y s t h a t f o l l o w e d t h e r e o p e n i n g , t h ea b u t m e n t s w e r e b a c k f i l l e d t o b e t t e r s u p p o r t t h e b r i d g el o a d s . R a p i d s e t L a t e x M o d i f i e d C o n c r e t e ( L M C ) w a sp l a c e d o v e r t h e s a w c u t g r o v e s , a n d e p o x y r e s i n w a sa d d e d t o t h e a b u t m e n t s u r f a c e s a s a p r o t e c t i v e c o a t i n g ,a s s h o w n i n F i g u r e C - 1 1 7 ( R u z z i e t a l . n . d . ) .Figure C-113. Lidar Scan (Ruzzi et al. n.d.)Figure C-114. Abutment Cap (Ruzzi et al. n.d.)Figure C-115. Installation of Precast Elements (Ruzzi et al. n.d.)

227C.26.5 ChallengesT h e b r i d g e w a s l o c a t e d i n a n u r b a n a r e a , w i t h ar e s i d e n t i a l h o m e a d j a c e n t t o t h e s t r u c t u r e . T h e l i m i t e dr i g h t o f w a y ( R O W ) r e s t r i c t e d t h e w o r k a r e a a r o u n d t h eb r i d g e , w h i c h i s o n e o f t h e r e a s o n s w h y A B C w a s s oa p p e a l i n g t o u s e i n t h e f i r s t p l a c e . F u r t h e r m o r e , t h ep r o x i m i t y o f o v e r h e a d p o w e r l i n e s l i m i t e d t h e s i z e a n dp l a c e m e n t o f c r a n e s f o r l i f t i n g e l e m e n t s i n t o p l a c e .S t r a t e g i c p l a n n i n g w a s c o n d u c t e d t o e n s u r e a l le q u i p m e n t w o u l d f i t o n s i t e . O n e a c h e l e m e n t , m a r k sw e r e p l a c e d t o i n d i c a t e w h e r e t h e p i e c e s h o u l d b e l i f t e d( R u z z i e t a l . n . d . ) .T h e b r i d g e ’ s g e o m e t r y c o n s i s t e d o f a c u r v e a n ds k e w , m a k i n g t h e d e s i g n c h a l l e n g i n g . T o a c c o m m o d a t et h e c u r v a t u r e , t h e c e n t e r s t e e l c o m p o s i t e b e a m s w e r e a l ls p a c e d a t c o n s i s t e n t s p a c i n g s , b u t t h e o v e r h a n g s v a r i e d ,a d j u s t i n g a s n e e d e d t o m a t c h t h e r o a d w a y g e o m e t r y( R u z z i e t a l . n . d . ) .I t w a s d i f f i c u l t t o s e t t h e p r e c a s t a b u t m e n t c a p s l e v e l ,e v e n w i t h s h i m s , s o i n v e s t i g a t i n g a n o t h e r m e t h o d f o rs e t t i n g t h e m i n p l a c e w o u l d h e l p f o r f u t u r e p r o j e c t s( R u z z i e t a l . n . d . ) .C.26.6 Innovations and Lessons LearnedC.26.6.1 3D Renderings of ConstructionSequencingT h e 3 D r e n d e r i n g s a n d c o n s t r u c t i o n s e q u e n c i n gc h e c k w i t h B I M w a s h e l p f u l f o r t h e p r o j e c t . E v e n i nc a s e s w h e r e h i g h q u a l i t y a s - b u i l t s a r e a v a i l a b l e , B I Ms h o u l d s t i l l b e e n c o u r a g e d t o p r o v i d e a b e t t e r v i s u a lu n d e r s t a n d i n g f o r t h e c o n t r a c t o r a n d t h e w o r k e r s , a ss h o w n i n F i g u r e C - 1 1 8 ( R u z z i e t a l . n . d . ) .Figure C-117. UHPC Pouring of Joint (Ruzzi et al. n.d.) Figure C-116. LMC Placement (Ruzzi et al. n.d.)Figure C-118. Building Information Model of Bridge (Ruzzi et al. n.d.)

228C.27 Washington ABC I-5/US 12 at Grand Mound 2011 [Other]Table C-27. Washington ABC I-5/US 12 at Grand MoundCase Study Name/ Date Washington ABC I-5/ US 12 at Grand Mound (2011)L ocation Washington, USAEvent Type OtherBridge Name I-5/ US 12 Bridge at Grand MoundScope/ Costs Total Bridge Replacement, total cost of $ 15.52 millionPlanning Techniques/ Tools Design-bid-buildEvent Response Diverted traffic to keep vehicles moving during demolition and repair Assessment Techniques/ Tools N/ ARapid Restoration Type Prefabricated bridge elements and systems Innovations • Precast columns, pier caps, and diaphragms• Integration of architectural details with precast columns andpier caps• Still met seismic requirements while using precastelementsC.27.1 IntroductionT h e I - 5 / U S 1 2 B r i d g e a t G r a n d M o u n d i nW a s h i n g t o n w a s d e t e r i o r a t e d a n d n e e d e d t o b er e p l a c e d . F o r t h e r e p l a c e m e n t o p t i o n , W S D O T d e c i d e dt o u s e A B C t o r e d u c e t r a f f i c i m p a c t s , i m p r o v e w o r kz o n e s a f e t y , a n d r e d u c e t h e o v e r a l l l i f e c y c l e c o s t . T h er e p l a c e m e n t s t r u c t u r e u s e d ( 1 5 ) 3 5 ” d e e p p r e s t r e s s e dd e c k b u l b t e e g i r d e r s w i t h a 5 ” c a s t - i n - p l a c e c o v e r i n g ,a s s h o w n i n F i g u r e C - 1 1 9 . T h i s w a s a d e m o n s t r a t i o np r o j e c t s p o n s o r e d b y t h e H i g h w a y s f o r L I F E p r o g r a m .T h e U n i v e r s i t y o f W a s h i n g t o n p e r f o r m e d s e v e r a l t e s t sa s a p r o o f o f c o n c e p t b e f o r e i m p l e m e n t a t i o n , s u c h a s t h ep r e c a s t c o l u m n - t o - f o o t i n g c o n n e c t i o n s . O t h e r p r e c a s tc o m p o n e n t s i n c l u d e d t h e c o l u m n s , p i e r c a p s , g i r d e r s ,a n d d i a p h r a g m s . O v e r a l l , t h e n e w b r i d g e u s e d p r e c a s tc o m p o n e n t s w i t h c a s t - i n - p l a c e c o n c r e t e j o i n t s t o c r e a t ea l a s t i n g s t r u c t u r e a n d d e m o n s t r a t e d t h e a b i l i t y t o u s eA B C t e c h n o l o g i e s o n a g r e a t e r s c a l e ( K h a l e g h i e t a l .2 0 1 2 ) .C.27.1.1 Event ResponseT r a f f i c w a s d i v e r t e d a r o u n d t h e w o r k z o n e t o k e e p v e h i c l e s m o v i n g a n d t o i n c r e a s e w o r k e r s s a f e t y b e f o r et h e p r o j e c t b e g a n .Figure C-119. Plan Drawings (Courtesy of PCI Journal, Khaleghi et al. 2012)

229C.27.2 Emergency PlanningC.27.2.1 Crowdsourcing and Information GatheringT h i s p r o j e c t s e r v e d a s a P i l o t P r o g r a m f o r W S D O T t o t e s t t h e f e a s i b i l i t y o f A B C I m p l e m e n t a t i o n , s ot h e r e w a s n o i n f o r m a t i o n c o l l e c t e d b y t h e p u b l i c a s p a r t o f i n f o r m a t i o n g a t h e r i n g .C.27.3 AssessmentT h e e x i s t i n g s t r u c t u r e w a s d e t e r i o r a t e d a n d n e e d e d r e p l a c e m e n t – t h e r e w a s n o e x t r e m e e m e r g e n c y e v e n t( i . e . , e a r t h q u a k e , c o l l i s i o n s , e t c . ) t h a t l e d t o t h i s d e c i s i o n . T h u s , i t i s a s s u m e d t r a d i t i o n a l a s s e s s m e n tt e c h n i q u e s a s p a r t o f r o u t i n e i n s p e c t i o n s w e r e u s e d t o m a k e t h i s d e t e r m i n a t i o n . C.27.4 Rapid RestorationC.27.4.1 ProcurementT h e p r e c a s t c o m p o n e n t s w e r e m a n u f a c t u r e d o f f s i t e a n d t r u c k e d t o t h ep r o j e c t . A s a t e s t , W S D O T w a n t e d t h e c o l u m n s t o b e c a s t i n s e g m e n t s t os e e h o w e a s i l y t h e y c o u l d b e l i n k e d t o g e t h e r . T h e c o l u m n s w e r e s h o r te n o u g h t o b e t r a n s p o r t e d i n c o m p l e t e s e c t i o n s , b u t t h i s m a y n o t b e t h ec a s e f o r l a r g e r s t r u c t u r e s . T h e b r i d g e c o m p o n e n t s w o u l d t h e n b ea s s e m b l e d i n a s o c k e t - s t y l e c o n n e c t i o n h i g h l i g h t e d i n F i g u r e C - 1 2 0( K h a l e g h i e t a l . 2 0 1 2 ) .C.27.4.2 Permanent StructureB e f o r e s e t t i n g t h e c o l u m n s , t h e r e g i o n a r o u n d t h e b e n t s w e r e e x c a v a t e d ,t h e f o o t i n g f o r m s w e r e s e t i n p l a c e , a n d t h e c o n c r e t e p o u r e d . T h e n , t h ec o l u m n s e g m e n t s , w h i c h w e r e m a n u f a c t u r e d o f f s i t e , w e r e l i f t e d i n t op l a c e a n d r e i n f o r c e m e n t b a r s w e r e a d d e d a n d g r o u t e d t o c r e a t e o n ec o h e s i v e u n i t . T h e r e m a i n i n g s e g m e n t o f t h e c o l u m n s w e r e s t r u n g o n t ot h e e x p o s e d r e i n f o r c e m e n t b a r s , i n t h e s a m e f a s h i o n a s s t r i n g i n g b e a d s o na n e c k l a c e , a s s h o w n i n F i g u r e C - 1 2 1 .F o r s e t t i n g t h e p i e r c a p b e a m , s h i m s a n d b r a c i n g w e r e s e t , a s s h o w n i nF i g u r e C - 1 2 2 . T h e n t h e p r e c a s t b e a m s e g m e n t s w e r e l i f t e d i n t o p l a c e a n dg r o u t w a s u s e d t o b o n d t h e c a p b e a m s , c o l u m n , a n d r e i n f o r c e m e n tt o g e t h e r . T h e c h a l l e n g e w a s t h e e n s u r e a p r o p e r m o m e n t t r a n s f e r f r o m t h ec a p b e a m t o t h e c o l u m n s , a s f u r t h e r d i s c u s s e d i n t h e f o l l o w i n g s e c t i o n s .O n c e t h e c a p b e a m w a s l o w e r e d , t h e n g i r d e r s w e r e s e t , a n d f i n a l l y t h e 5 ”t h i c k t o p p i n g w a s p o u r e d . T h e d i a p h r a g m s w e r e a d d e d a f t e r t h e t o p s l a bw a s c a s t . L a s t l y , t h e s i d e w a l k a n d t r a f f i c m e d i a n s w e r e c a s t - i n - p l a c e , a n dt h e b r i d g e w a s c o m p l e t e d ( K h a l e g h i e t a l . 2 0 1 2 ) .C.27.5 ChallengesT h e r e w a s a c o n s i d e r a b l e a m o u n t o f c o n g e s t i o n a t t h e c a p b e a m c l o s u r e . F o r t h i s p r o j e c t , t h e r e w a s e x t r aa t t e n t i o n t o d e t a i l i n g , s o t h i s w a s n o t a n i s s u e , b u t f o r f u t u r e p r o j e c t s , t h i s s h o u l d s t i l l b e k e p t i n m i n d t oFigure C-120. Integrated Footings and Bent Cap with Columns (Courtesy of PCI Journal, Khaleghi et al. 2012)Figure C-121. Setting of a Column Segment (Courtesy of PCI Journal, Khaleghi et al. 2012)

230e n s u r e a l l t h e b a r s l i n e u p w h e n t h e s e g m e n t s a r e l i n k e d i n t op l a c e . A n y m i s a l i g n m e n t w i t h d e t a i l i n g c o u l d p o s e m a j o rp r o b l e m s .F u r t h e r m o r e , a n o t h e r c h a l l e n g e f o c u s e d o n g r o u t i n g t h ec o l u m n s e g m e n t s a n d e n s u r i n g p r o p e r c l o s u r e o f t h e c a p b e a ms e g m e n t s . T h i s w a s f u r t h e r c o m p l i c a t e d b y t h e b r i d g e s k e w .M o r e p r a c t i c e w i t h t h e s e t y p e s o f d e t a i l s a n d c o n s t r u c t i o n , s u c ha s j o i n t s a n d f i n i s h e s , w o u l d b e n e e d e d b e f o r e m a s s p r o d u c t i o no f s i m i l a r - t y p e s t r u c t u r e s i n t h e f i e l d , a s w a r n e d b y t h ec o n t r a c t o r ( K h a l e g h i e t a l . 2 0 1 2 ) .A n o t h e r c h a l l e n g e w a s e n s u r i n g t h e r i g h t t o l e r a n c e s w e r eu s e d w h e n s e t t i n g c o m p o n e n t s . I f c l o s u r e s w e r e t o o t i g h t , t h ej o i n t s w e r e d i f f i c u l t t o g r o u t ( W S D O T 2 0 1 6 ) .L a s t l y , i t w a s o f t h e u t m o s t i m p o r t a n c e t h e b e a m c a p t oc o l u m n c o n n e c t i o n w a s f u l l y g r o u t e d . T h i s w o u l d e n s u r e t h e p r o p e r m o m e n t t r a n s f e r f r o m t h e g i r d e r s t ot h e g r o u n d . T h i s d e s i g n s i m u l a t e s a c o n t i n u o u s s p a n , b u t i m p r o p e r d e t a i l i n g w o u l d c r e a t e t w o s i m p l e s p a n s ,w h i c h w o u l d n o t t r a n s f e r m o m e n t , a n d d i s t r i b u t e t h e s t r u c t u r e l o a d s d i f f e r e n t l y t h a n d e s i g n e d .C.27.6 Innovations and Lessons LearnedC.27.6.1 Cast-In-Place vs. Precast ColumnsO n e a r e a o f t r o u b l e w a s t h e p r e c a s t c o l u m n s . T h e c o n t r a c t o rb e l i e v e d u s i n g a s i n g l e p r e c a s t c o l u m n i n s t e a d o f s e v e r a l ,s m a l l e r s e g m e n t s w o u l d b e e a s i e r t o i n s t a l l a n d s a v e t i m e . T h i sm a y n o t b e f e a s i b l e f o r l a r g e r p r o j e c t s , b u t f o r t y p i c a l b r i d g ec o l u m n h e i g h t s , a s i n g l e c o l u m n w o u l d b e m o r e e f f i c i e n t( K h a l e g h i e t a l . 2 0 1 2 ) . M o r e o v e r , t h e c o n t r a c t o r d i d i n d i c a t e t h ep r e f e r e n c e o f c a s t - i n - p l a c e c o l u m n s o v e r p r e c a s t b u t w o u l d b ew i l l i n g t o s w i t c h i f r e q u i r e d t o d o s o ( A c c e l e r a t e d B r i d g eC o n s t r u c t i o n U n i v e r s i t y T r a n s p o r t a t i o n C e n t e r n . d . a ) .F u r t h e r m o r e , i t w a s f o u n d t h a t g r o u t i n g a l l j o i n t s a t o n c e f o r t h ed e c k a n d s u p e r s t r u c t u r e w a s e a s i e s t , a s a h i g h - p r e s s u r e p u m pw o u l d e n s u r e a l l t h e d u c t s w e r e a d e q u a t e l y f i l l e d .C.27.6.2 Wider JointsW i d e r j o i n t s m a d e i t e a s i e r t o g r o u t d e c k j o i n t c o n n e c t i o n ,a n d u s i n g J h o o k s t i r r u p s i n s t e a d o f U h o o k s f o r t h e b e a m c a p sw o u l d a l s o h a v e m a d e i t e a s i e r f o r p l a c e m e n t , a s s h o w n i nF i g u r e C - 1 2 4 ( K h a l e g h i e t a l . 2 0 1 2 ) .C.27.6.3 Architectural DetailingA b e n e f i t t o u s i n g p r e c a s t o v e r c a s t - i n - p l a c e a n d o t h e rt r a d i t i o n a l m e t h o d s i s t h e c o n v e n i e n c e o f a d d i n g a r c h i t e c t u r a lf e a t u r e s t o t h e b r i d g e s , a s s h o w n i n F i g u r e C - 1 2 3 T h i s c a n b e d o n e b y t h e m a n u f a c t u r e r a t t h e p l a n t ,r e d u c i n g t h e f i e l d t i m e n e c e s s a r y f o r s u c h d e t a i l s w h i l e s t i l l m a k i n g t h e s t r u c t u r e a e s t h e t i c a l l y p l e a s i n g( W S D O T 2 0 1 6 ) .Figure C-122. Setting of a Pier Cap Segment (Courtesy of PCI Journal, Khaleghi et al. 2012)Figure C-124. Narrow Joints (Courtesy of PCI Journal, Khaleghi et al. 2012)Figure C-123. Architectural Column and Pier Cap Detailing (Courtesy of PCI Journal, Khaleghi et al. 2012)

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