The SR 520 Evergreen Point Floating Bridge is a 2,652m long project crossing Lake Washington near Seattle, in the USA, combining both floating and fixed base bridge segments.
A unique design
The unique construction consists of a 5,135ft (1,566m) long low-rise structure of precast segments supported at a typical 9m 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 2.5ft (0.76m) with a total deck width of 113’-4” (34.6m) carrying 6 lanes of traffic and a pedestrian walkway.
SYSTRA is responsible for technical oversight and construction engineering for the cast-in-place segmental twin box-girder long span at the east side of the project, which has a total length of 192m and a main span of 98m. Both structures are pre-designed to be expandable for two additional mass transit lanes in the future.
The SR 520 Evergreen Point Floating Bridge has received the following honors:
- 2017 American Council of Engineering Companies
- Grand Conceptor Award
- 2016 Design-Build Institute of America
- National Award of Merit
- Excellence in Design
Project Key figures
- Total length: 1,566m
- Width: 34,6m
- Thickness: 0,76m
- 6 traffic lanes and a pedestrian walkway
- 77 concrete pontoons
- 58 anchors
- 74,000 vehicles per day