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SR 520 - Floating Bridge and Landings Project

The design-build team will continue to design many elements of this project even as construction gets under way.
The New SR 520 Bridge and Approaches will be built between Seattle and Medina.

Project Photos


May 2016


Decommissioning of the old bridge begins as early as Monday, April 25. Learn more about the process and what to expect on the What’s Happening Now page.

Want to bike or walk across SR 520?
Please visit the new SR 520 Bicycle and Pedestrian Connections page for information about your options to pedal or walk along the SR 520 corridor.

What's happening now?

    The SR 520 Floating Bridge and Landings project replaces the existing floating bridge and approaches from the future west approach structure east of Foster Island in Seattle to Evergreen Point Road in Medina.

    Why is WSDOT replacing the SR 520 floating bridge and landings?

    After over a half century of use, the existing floating bridge is showing its age. The bridge's pontoons have become vulnerable to windstorms and its support columns are vulnerable to earthquakes.

    Additionally, the existing bridge only has two lanes in each direction, no shoulders and no HOV lanes. Adding transit/HOV lanes, shoulders and a bicycle/pedestrian path will provide greater reliability and more options to accommodate growth in the region.

    The bicycle/pedstrian path on the new bridge will also connect to regional trails on either side of Lake Washington creating additional recreation opportunities.

    The End Result

    • A safer structure that is resistant to windstorms up to 89 mph.
    • Two general-purpose lanes and one transit/HOV lane in each direction.
    • Wider, safer shoulders that will allow vehicles to pull over in the case of a breakdown.
    • A 14-foot-wide bicycle and pedestrian path on the north side of the bridge.
    • Ability to accommodate future light rail if the region chooses to fund it in the future.

    Project Benefits

    • Except for occasional short-term closures, SR 520 will remain open through construction of the new floating bridge.
    • The new floating bridge will improve transit reliability and travel times.
    • Building components of the bridge in Grays Harbor, Tacoma and Kenmore provides hundreds of jobs throughout Western Washington.

    What is the project timeline?

    • Late 2011 - Began pontoon construction in Tacoma.
    • Early 2012 - Began anchor construction in Kenmore.
    • Spring 2012 - Began bridge construction on eastern shore of Lake Washington.
    • Spring 2016 - Anticipated date to open new floating bridge to drivers.
    • Late 2016 - Anticipated date for removal of the existing floating bridge.

    Financial Information

    This project is funded by a variety of state and federal sources, including SR 520 tolling that began in December 2011.

    Visit the SR 520 Budget and Performance page for additional information. 

    This project had a construction change order of more than $500,000. View all change orders.

    How can I get more information?


    Construction Hotline: 425-576-7098

    Infoline: 1-888-520-NEWS (6397)

    Twitter: @WSDOT_520

    Mail: I-5 to Medina: Bridge Replacement and HOV Project
    SR 520 Bridge Replacement and HOV Program
    999 3rd Avenue, Suite 2200
    Seattle, WA 98104

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