Washington: Eastbound, State Route 18 Over State Route 516, King County

Federal Highway Administration2000PDFBriefUnited States. Federal Highway AdministrationTurner-Fairbank Highway Research CenterUnited States. Federal Highway AdministrationWashingtonHighway bridgesHigh performance concreteBridge designBridgesCompressive strengthDesignPrestressed concrete bridgesPrestressed concreteHigh-Performance Concrete programFHWA-RD-00-124The high-performance concrete bridge carrying eastbound State Route 18 traffic over State Route 516 in King County, Washington is a three-span continuous structure, with a center span of 42 m (137 ft) and side spans of 24 m (80 ft). Pretensioned concrete Washington State Department of Transportation W74G girders were used. The bridge deck is 11.6 m (38 ft) wide, carrying two 3.7-m (12-ft) lanes and 1.2-m (4-ft) and 3.0-m (10-ft) shoulders. The bridge is designed for earthquake zone "C" (acceleration coefficient = 0.25 g). The design used the new AASHTO Load and Resistance Factor Design (LRFD) bridge specifications. Using high-strength HPC in conjunction with the 15.2-mm (0.6-in.) strands, two fewer girders per span were required than if conventional concrete and strands had been used. The structure's life will be enhanced because of the durability benefits associated with HPC.119