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SR 520 - West Approach Bridge North Project Construction Overview

Construction for the SR 520 West Approach Bridge North began in September 2014.


What can I expect during construction?

As the West Approach Bridge North project moves forward, WSDOT is committed to employing best management practices throughout construction to minimize impacts on the community and traveling public, including:

  • Providing advance notice of noisy work and complying with city of Seattle noise permits.
  • Using noise shields on generators, compressors, jackhammers and other loud equipment.
  • Conducting pre-construction inspections of front-line properties.
  • Marking protected trees with high-visibility fencing.
  • Installing tire washes to prevent tracking of dirt and gravel on local streets.
  • Keeping spill-response kits and containment booms on all barges and marine vessels.
  • Using directional lights and shielding.
  • Applying water to dust-generating work areas and activities.
  • Following a no idling policy for construction vehicles.

How will WSDOT build the West Approach Bridge North project?

See the image below for an overview of the steps needed to construct the new West Approach Bridge North.


Click image for larger, printable version. (pdf 390 kb)

Fall 2014 - Began construction

  • Installed construction fencing and performed environmental protection measures around project boundaries
  • Marked restrictions to shoreline and trails
  • Set up field trailers and equipment in staging areas
  • Removed trees and vegetation as necessary and marked trees to be protected, including on Foster Island and Lake Washington Boulevard
  • Demolished segments of the unused R.H. Thomson ramps
  • Installed piles to establish work bridge access from Foster Island and the former Museum of History and Industry (MOHAI) area
  • Began abatement and prepared for the demolition of the former MOHAI building

2015

  • Completed abatement and demolition of the former MOHAI building
  • Began construction of local street and sidewalk improvements on Montlake Boulevard and East Lake Washington Boulevard
  • Began construction of the temporary westbound SR 520 off-ramp to Montlake Boulevard
  • Continued building the temporary work bridge and began building the bridge foundations, substructure and superstructure of the permanent West Approach Bridge North (WABN)
  • Completed the first phase of R.H. Thomson ramps demolition
  • Completed the temporary westbound SR 520 off-ramp to Montlake Boulevard and opened to traffic in August 2015
  • Began demolition of existing westbound SR 520 off-ramp to Montlake Boulevard
  • Closed the 24th Avenue East bridge and began extending 24th Avenue East bridge over SR 520 to build the new westbound SR 520 off-ramp to East Lake Washington Boulevard

2016

  • Completed temporary westbound SR 520 off-ramp to East Lake Washington Boulevard and opened to traffic in Jan. 2016
  • Continued demolition of the existing westbound SR 520 off-ramp to East Lake Washington Boulevard, the existing westbound SR 520 off-ramp to Montlake Boulevard and the unused R.H. Thomson ramps
  • Continued building new off-ramps, foundations, substructure and superstructure of the permanent WABN along the entire length of the new bridge
  • Began removing extension piers of the temporary work bridge

2017

  • Continue to remove temporary work bridge
  • Complete demolition of the existing westbound SR 520 off-ramp to East Lake Washington Boulevard, the existing westbound SR 520 off-ramp to Montlake Boulevard and the unused R.H. Thomson ramps
  • Connect new West Approach Bridge North to the new floating bridge
  • Open the new WABN to traffic in summer 2017
  • Open the regional shared-use path to traffic in fall 2017

How can I learn about upcoming construction activities?

You can learn more about upcoming construction activities by visiting our What’s Happening Now webpage or by signing up for our WABN email updates. To sign up for email updates, enter your email and sign up for the alert called “SR 520 West Approach Bridge North Project” located under the “Construction Reports” section.