SR 520 EVERGREEN POINT FLOATING BRIDGE
The SR 520 Evergreen Point Floating Bridge is an 8,700 ft long project crossing Lake Washington near Seattle, Washington, combining both floating and fixed base bridge components. SYSTRA IBT developed the unique design for the 5,135 ft (1,566 m) long low-rise structure consisting of precast segments supported at a typical 30 ft spacing on top of the floating bridge. This innovative two-way post-tensioned structure is designed to be low profile, with a maximum thickness of 2.5 ft (0.76 m) while carrying 6 lanes of traffic plus a pedestrian walkway for a total deck width of 113’-4"(34.6 m). SYSTRA IBT also provided for technical oversight and construction engineering services for the cast-in-place segmental twin box-girder long span at the east side of the project, which has a total length of 629 ft and a main span of 320 ft. Both structures are pre-designed to be expandable for two additional mass transit lanes in the future. Design-build project.
SR 520 Floating Bridge has won the 2017 “Grand Conceptor” Award signifying the year’s most outstanding engineering achievement in the 50th Anniversary Engineering Excellence Awards (EEA).