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/297009
R e p l a c e m e n t o f t h e C r a i g C re e k Bridge carrying State Highway 99, near Red Bluff, Calif., began in the fall of 2011 as the California Department of Transportation (Caltrans) undertook its third official accelerated bridge construction (ABC) project under the Federal Highway Administration's (FHWA's) Every Day Counts initiative. This initiative is designed to identify and deploy innovation aimed at shortening project delivery, enhancing the safety of our roadways, and protecting the environment. T h e C a l t r a n s p r o j e c t i n c l u d e d replacement of an aging, scour-critical, three-span bridge with a single-span structure. Bids were opened on April 20, 2010, with the intent of replacing the old bridge between July 15 and October 15 in two phases, keeping one-lane traffic on each half of the bridge. As bid, this would require temporary shoring for the roadway and temporary bents to support the old bridge while carrying traffic as the other half gets demolished; thereby, allowing the first stage of the new bridge to be constructed. Traffic would be handled with a combination of temporary traffic signals and flaggers. One-lane traffic would then be shifted to the first stage of the new bridge while the remaining old bridge would be removed and replaced. In order to complete the bridge as planned in two stages within the short construction window permitted by the regulatory agencies. ABC technology using prefabricated bridge elements and systems (PBES) components, was selected over conventional construction methods. The bridge design comprised 11 adjacent 3.5-ft-deep by 4-ft-wide precast, prestressed concrete box beam units; a 5-in.-thick, cast-in-place concrete deck; precast concrete abutments and wingwalls; and twelve 2-ft-diameter, cast- in-steel-shell (CISS) concrete piles. The designer chose a 4 ksi site-cast concrete deck to provide composite action, in part due to concerns of differential live load deflections between adjacent box beam sections affecting long-term deck durability. After girders were set in place, five 1 3 / 8 -in. high-strength tie rods were installed, with one at each end diaphragm and the ¼ span points, and the girders were snugged together by stressing the rods to 20% of the total post-tensioning force. After girders were snug, the 18-in.-deep longitudinal keyways were grouted with nonshrink grout and the grout was allowed to reach 5 ksi strength before bringing each rod to the final post- tensioning force of 130 kips. Tie rod ducts were then grouted and exterior bearing plate blockouts were filled with structural concrete and finished to match the rest of the girder. profile CRAIG CREEk BRIDGE / RED BLuFF, CALIFORNIA BRIDGE DESIGN ENGINEER: California Department of Transportation, Sacramento, Calif. BRIDGE CoNSTRuCTIoN ENGINEER: California Department of Transportation, Chico, Calif. GENERAl CoNTRACToR: Blaisdell Construction Inc., Anderson, Calif. PRECASTER: Con-Fab, Lathrop, Calif., a PCI-certified producer READy-MIx CoNCRETE SuPPlIER: A&A Concrete, Chico, Calif. PoST-TENSIoNING CoNTRACToR: Schwager Davis Inc., San Jose, Calif. The new 108-ft-long, Craig Creek Bridge, built in 2011 with a crack-free deck and a three-day cure. All Photos: Caltrans. by Sonny Fereira, Caltrans Every day counts in improving mobility Accelerated Bridge Construction over Craig Creek 26 | ASPIRE , Fall 2013 P R O J E C T Book_Fall13ASPIRE.indb 26 9/6/13 12:05 PM