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SR 520 - West Approach Bridge North Project

Project Status: Design
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

December 2014

Stay up to date on West Approach Bridge North construction

  • What's happening now? Get the latest on construction progress of the West Approach Bridge North Project (WABN).
  • The Arboretum Waterfront Trail is now open and safe for public use. Enjoy the trail this holiday season and remember to stay safe while walking near the temporary work bridge as it is an active work zone.
  • Join us for our next WABN monthly meeting with the contractor on Jan. 7 from 5:30 - 6:30 at the Graham Visitors Center.
  • See our latest email update on our website. Haven't joined our subscriber list yet? Sign up for our WABN email updates today.
  • Missed our Dec. 3 monthly meeting? Check out the meeting materials online.
  • Visit the Orange Page to learn about upcoming highway closures and other construction activities.
  • Contact project staff with questions about the project or construction activities.

Overview 

The West Approach Bridge North Project is the next phase of construction of the SR 520 Bridge Replacement and HOV Program. The new approach bridge will be open 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 existing west approach bridge is a fixed structure that connects the current floating bridge to the Montlake interchange. The hollow columns supporting the existing 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.
 
While funding is not yet available to build the south (eastbound) half of a new west approach bridge, construction is moving forward with the north (westbound) half. The existing, seismically vulnerable approach bridge needs to be replaced. If the aging structure fails in a severe earthquake before a south-half replacement can be built, the new West Approach Bridge North will have the width to support four lanes of traffic in an interim configuration.

The End Result

When completed in 2017, the new West Approach Bridge North will carry 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 funding is provided for the 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, a new stormwater treatment facility at the site of the old Museum of History and Industry (MOHAI), 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, a public park north of SR 520, and a stormwater treatment facility at the old MOHAI site for highway runoff.
  • 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: Open new bridge 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 Costs, Funding and Tolling 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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