THE CONCRETE BRIDGE MAGAZINE

SPRING 2016

ASPIRE is a quarterly magazine published by PCI in cooperation with the associations of the National Concrete Bridge Council. The editorial content focuses on the latest technology and key issues in the Concrete Bridge Industry.

Issue link: http://www.aspiremagazinebyengineers.com/i/657823

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S TAT E 38 | ASPIRE Spring 2016 N o r t h C a r o l i n a ' s b a c k l o g o f s t r u c t u r a l l y d e f i c i e n t b r i d g e s h a s b e e n t a r g e t e d b y t h e s t a t e 's l e g i s l a t u r e for both fiscal years 2016 and 2017. With $ 1 5 0 m i l l i o n a d d e d t o t h e b u d g e t o v e r t h e t w o - y e a r p e r i o d , t h e N o r t h C a r o l i n a D e p a r t m e n t o f Tr a n s p o r t a t i o n ( N C D O T ) is using a variety of techniques, including bridge prioritization, design-build deliver y m e t h o d s , a n d b u n d l i n g o f p r o j e c t s t o m a x i m i z e t h e e f f e c t i v e n e s s o f t h i s mandate. The addition of an ex tra $50 million in 2016 and $100 million in 2017 to address d e f i c i e n t b r i d g e s w a s p r o v i d e d w i t h t h e dir ectiv e to addr ess the state's cor e needs b y u s i n g o b j e c t i v e c r i t e r i a r a t h e r t h a n r e a c t i n g t o p o l i t i c a l p r e s s u r e s . T h i s f u n d i n g w i l l s i g n i f i c a n t l y r e d u c e t h e 2167 str ucturally deficient bridges (out of 13,400) in the state. NCDOT is for tunate to have legislators in Nor th Carolina who see the gr owing pr oblem and understand the need to act now. A s with many states, Nor th Carolina saw a boom in post-war highway constr uction, a n d m a n y o f t h o s e b r i d g e s h a v e r e a c h e d t h e e n d o f t h e i r u s e f u l l i v e s . O v e r t h e y e a r s , t h a t t o t a l c o n t i n u e s t o g r o w a n d r e q u i r e s r e p l a c e m e n t s t h a t p r o v i d e f e w disr uptions to the traveling public. To d e t e r m i n e h o w b e s t t o o p t i m i z e t h e f u n d i n g , N C D O T h a s r a n k e d t h e b r i d g e s u s i n g i t s P r i o r i t y R e p l a c e m e n t I n d e x ( P R I ) . T h i s i n d e x a s s i g n s v a l u e s t o a number of bridge measures (for example, average daily traffic, load rating, str ucture c o n d i t i o n r a t i n g , a n d d e t o u r l e n g t h ) a n d d e t e r m i n e s r e p l a c e m e n t p r i o r i t i e s . I n a d d i t i o n t o t h a t a p p r o a c h , N C D O T initiated a low-impact bridge replacement p r o g r a m , w h i c h f o c u s e s o n r e p l a c i n g r ural, low-v olume bridges in kind rather t h a n p r o v i d i n g s u b s t a n t i a l u p g r a d e s . This ensures project s can be completed as quickly as possible and spreads the money to more bridges needing replacement. Design-Build Method Growing N C D O T a l s o m a k e s u s e o f t h e d e s i g n - b u i l d d e l i v e r y m e t h o d t o e n c o u r a g e i n n o v a t i o n a n d c u s t o m e f f i c i e n c i e s b y e a c h b i d d e r. D e s i g n - b u i l d h a s b e c o m e a n i m p o r t a n t t o o l a s i t s p e e d s u p t h e c o n s t r u c t i o n p r o c e s s b y a l l o w i n g s i t e work to begin as designs ar e completed. O n e o f t h e s t a t e ' s f i r s t s u c c e s s e s w i t h d e s i g n - b u i l d p r o j e c t s w a s t h e U S R o u t e 1 7 Wa s h i n g t o n B y p a s s p r o j e c t i n B e a u f o r t C o u n t y. T h e p r e c a s t c o n c r e t e b r i d g e c o n s i s t s o f 1 4 0 s p a n s ( 1 1 6 s p a n s p l u s t w o p a r a l l e l s t r u c t u r e s o f 1 2 s p a n s ) t h a t a r e e a c h a b o u t 1 2 1 f t l o n g . B i d d e r s w e r e s c o r e d o n t h e i r c r e a t i v i t y a n d e s t i m a t e d c o s t . A d j u s t m e n t s w e r e m a d e t o t h e p r o p o s a l t o l o w e r c o s t s b a s e d o n feedback. Larger projects often use the design- build process. Larger projects often use the design-build process, such as the ongoing replacement of the Herbert C. Bonner Bridge, an existing 2.5-mile-long structure in Dare County on the Outer Banks that serves as the only road access from the mainland to Hatteras Island. The 2.8-mile-long r eplacement str uctur e, which will parallel the existing bridge, will use a segmental box-girder design for the major spans and pr ecast concr ete gir ders for the appr oach str uctur es. Constr uction w i l l b e g i n t h i s s p r i n g . T h i s r e p r e s e n t s a major milestone, as the bridge has needed replacement for years but was held up due to legal actions. The work also includes an interim bridge o n N C 1 2 n e a r P e a I s l a n d t h a t r e p l a c e s t h e e x i s t i n g t e m p o r a r y b r i d g e t h a t w a s c o n s t r u c t e d o v e r a n i n l e t c r e a t e d d u r i n g Hurricane Irene in 2011. The interim bridge will be constructed with enough durability to last until a permanent solution is determined that is compatible with stakeholder interests. It will feature 47 spans of 50-ft-long cored- slab units, with vir tually the entire bridge composed of precast concrete elements. This construction, let under a separate design-bid- build project, has begun. NORTH CAROLINA The state's department of transportation uses weighting factors, bundling to gain most bang from legislature's extra funding in next 2 years g g g g by Tom Koch and Todd Garrison, North Carolina Department of Transportation The new Herbert C. Bonner Bridge in Dare County, N.C., which begins construction this spring, features a 2.8-mile-long structure composed of precast concrete segmental box girders and prestressed girder spans. The new bridge will parallel the existing one, the only access to Hatteras Island. Photo: HDR Inc.

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