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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 bicycle/pedestrian path

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: September 2017

 

Stay up to date on West Approach Bridge North construction

  • Heads up: Foster Island Trail to close Monday, Sept. 11, through Tuesday, Sept. 12. Get more information here.
  • SR 520 trail scheduled to open fall 2017.
    We know many of you are eager for the cross-lake bicycle and pedestrian path to open, and so are we! We’ll let you know as soon as we have a more specific date for the trail’s opening. 
  • See our latest email update on our website. Haven't joined our subscriber list yet? Sign up for our WABN email updates today.
  • Visit the Orange Page to learn about upcoming highway closures and construction activities.

      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 connects the current floating bridge to the Montlake interchange. The hollow columns supporting the old approach bridge are vulnerable to a catastrophic earthquake, and its four-lane roadway has narrow shoulders and no transit/HOV lanes or bicycle/pedestrian path. The old, seismically vulnerable approach bridge 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 existing 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 will extend 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 will implement local street improvements in the Montlake area, and a wider bicycle/pedestrian path on 24th Avenue East in Montlake.

      Project Benefits

      The West Approach Bridge North project will:

      • Build a new, seismically sound structure designed to modern earthquake standards.
      • Connect Montlake and the Eastside with new transit/HOV lanes.
      • Complete the bicycle and pedestrian connection across Lake Washington with a new, regional shared-use path.
      • Build environmental improvements such as a new Arboretum trail and a public park north of SR 520.
      • Enhance the Arboretum by removing the westbound Arboretum off-ramp and unused R.H. Thomson ramps.

      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 

      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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