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SR 520 - West Approach Bridge North Project

Project Status: Construction
Location map of West Approach Bridge North project
Location map of the West Approach Bridge North Project
 
Hollow columns on the existing west approach bridge

2006 photo of a damaged hollow column on the existing west approach bridge that has since been repaired. The columns for the West Approach Bridge North Project will be built to modern earthquake standards.


Rendering of the West Approach Bridge North transit/HOV lane

Renderings of the new West Approach Bridge North Project. Visit the design page for more.

Status

Last updated: December 2017

 

Stay up to date on West Approach Bridge North construction

 

  • SR 520 trail now open across Lake Washington
    SR 520's new bicycle and pedestrian path provides the first-ever non-motorized connection across Lake Washington alongside SR 520. Read our WSDOT blog article to learn more about this scenic, carbon-free travel option.
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      Overview 

      The West Approach Bridge North Project is the latest phase of construction of the SR 520 Bridge Replacement and HOV Program. The new approach bridge opened to traffic in summer 2017, extending SR 520’s three westbound lanes from the new floating bridge to the Montlake area in Seattle.

      Why is WSDOT building a new west approach bridge?

      The old west approach bridge, opened in 1963, is a fixed structure that now connects SR 520's eastbound lanes from Montlake to the new floating bridge. The hollow columns supporting the old approach bridge are vulnerable to a catastrophic earthquake. The seismically vulnerable structure needs to be replaced.
       
      While construction has not started on the south (eastbound) half of a new west approach bridge, the north (westbound) half opened to traffic in August 2017. If the old approach structure fails in a severe earthquake before a south-half replacement can be built, the new West Approach Bridge North has the width to support four lanes of traffic -- two lanes in each direction -- in an interim configuration. In fact, after the Montlake Phase of construction begins in late 2018, eastbound traffic between Montlake and the floating bridge will shift onto the West Approach Bridge North, with its three westbound lanes reduced to two lanes. This temporary configuration will allow crews to deconstruct the old west approach and build the West Approach Bridge South.   

      The End Result

      The new West Approach Bridge North carries westbound cars, trucks and buses from the new floating bridge to the Montlake area.
       
      Eastbound traffic will continue to use the old west approach structure until the Montlake Phase of construction begins in late 2018. Eastbound traffic ultimately will travel on a new West Approach Bridge South.
       
      Also, as a result of West Approach Bridge North construction, SR 520’s new bicycle and pedestrian path now extends from Montlake across Lake Washington to the Eastside, with connections to local and regional trails on both sides of the lake. The West Approach Bridge North project also made local street improvements in the Montlake area and created a wider bicycle/pedestrian path on 24th Avenue East in Montlake.

      Project Benefits

      The completed West Approach Bridge North project:

      • Built a new, seismically sound bridge structure designed to modern earthquake standards.
      • Connected Montlake and the Eastside with new transit/HOV lanes.
      • Completed the new, regional shared-use path's connection across Lake Washington to Montlake.
      • Provided for environmental improvements such as a new Arboretum trail, enhanced wetlands in the Union Bay Natural Area, and a new public park along Portage Bay.
      • Enhanced the Arboretum by removing the westbound Arboretum off-ramp and unused R.H. Thomson "ramps to nowhere."

      What is the project timeline?

      • Spring 2014: Advertise construction contract 
      • Summer 2014: Select contractor
      • Fall 2014: Begin construction 
      • Summer 2017: New bridge opened to traffic
      • Late fall 2017: SR 520 Trail opened between Montlake and new floating bridge 

      Financial Information

      The West Approach Bridge North Project is fully funded by state and federal sources.

      WSDOT awarded a $199.5 million contract to Flatiron West, Inc. to construct the West Approach Bridge North Project. 

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

      How can I get more information?
      Contact:

      Email: SR520bridge@wsdot.wa.gov  

      24-hour construction  hotline: 206-708-4657 

      Twitter: @WSDOT_520

      Construction email updates: https://public.govdelivery.com/accounts/WADOT/subscriber/new

      • Enter your email address
      • Sign up for the new alert called “SR 520 West Approach Bridge North Project” from the subscription list (located under the “Construction Reports” section)

      Mail: West Approach Bridge North Project
      SR 520 Bridge Replacement and HOV Program
      999 3rd Avenue, Suite 2200
      Seattle, WA 98104

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