{"id":6834,"date":"2017-01-01T12:04:30","date_gmt":"2017-01-01T12:04:30","guid":{"rendered":"https:\/\/www.systra.com\/ibt\/?post_type=projects&p=6834"},"modified":"2026-04-17T22:07:31","modified_gmt":"2026-04-17T22:07:31","slug":"sr-520-evergreen-point-floating-bridge-seattle-washington","status":"publish","type":"projects","link":"https:\/\/www.systra.com\/ibt\/project\/sr-520-evergreen-point-floating-bridge-seattle-washington\/","title":{"rendered":"SR 520 Evergreen Point Floating Bridge – Seattle, Washington"},"content":{"rendered":"\n
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Technical details<\/div>\n \t
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Customer<\/div>\n\t
Washington State Department of Transportation<\/div>\n\t <\/div>\n
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Dates<\/div>\n

Construction Completed: 2017<\/p>\n<\/div>\n <\/div>\n

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Localisation<\/div>\n
Seattle, Washington<\/div>\n <\/div>\n
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Partners<\/div>\n
Design\/Build Contractor: Kiewit-General-Manson JV, Prime Consultant: KPFF Consulting Engineers<\/div>\n <\/div>\n
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Activity<\/div>\n
SYSTRA IBT's Role: Bridge Design Consultant, conceptual design, detailed design, and construction engineering.<\/div>\n <\/div>\n \n \n <\/div>\n\n\n\n
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DESIGN-BUILD<\/h2>\n\n\n\n

Total Bridge Length: <\/strong>5,135 ft (1,565 m)
Width: <\/strong>113 ft (34.5 m) (six traffic lanes, shoulders, pedestrian walkway).<\/p>\n<\/div><\/div>\n<\/div>\n\n\n\n

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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.<\/strong> <\/p>\n\n\n\n

SYSTRA IBT developed a 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 ft-4 in (34.6 m).<\/p>\n\n\n\n

SYSTRA IBT also provided 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. <\/p>\n\n\n\n

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The SR 520 Evergreen Point Floating Bridge was the recipient of the 2017 \u201cGrand Conceptor\u201d Award signifying the year\u2019s Most Outstanding Engineering Achievement in ACEC’s 50th Anniversary of the Engineering Excellence Awards<\/strong>.<\/p>\n<\/div><\/div>\n\n\n\n

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Additional Awards:<\/h2>\n\n\n\n