I-5 - NB S 260th St to Duwamish River Br - Concrete Pavement Rehab and ADA

Project news

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This section of northbound I-5 was built in 1965 and designed to last about 25 years, it has now lasted more than 51 years. Much of the roadway is worn out, and drivers often notice bumps where concrete panels are broken. Cracks and ruts have developed in the lanes that now carry approximately 100,000 vehicles each day, and the worn out expansion joints must be replaced.

Project details
This project presents numerous challenges as crews are:

  • Replacing about 440 broken concrete panels, mostly during nighttime lane closures. 
  • Repaving about 4 miles of all lanes with asphalt between SR 516 and South 178th Street. 
  • Grinding off ruts and bumps. 
  • Replacing eight expansion joints on the Interurban Avenue and Duwamish River bridges. 
  • Rehabilitating the Interurban Avenue and Duwamish River bridge decks.
  • Creating better sidewalk connections for people of all abilities at several intersections. 

Work progress
Contractor crews made substantial progress on northbound I-5 during 12 weekend-long closures from June-November 2017:

  • Finished the crack and seat portion of the work on four miles between SR 516 and Southcenter.
  • Finished paving all lanes between SR 516 and Southcenter.
  • Replaced more than 300 broken concrete panels.
  • Replaced the four expansion joints at Interurban Avenue.
  • Replaced four expansion joints on the Duwamish River Bridge.
  • Repaved the both sides of the Interurban Avenue overpass and Duwamish River Bridge.

Needs & Benefits

This preservation and improvement project will create safer and improved driving conditions for the tens of thousands of travelers who rely on the interstate daily. It also will extend the useful life of I-5 for decades to come. This project is part of a multi-year effort to preserve I-5 through King County.

  • Preservation
    • Replacing broken concrete panels, repaving and grinding the interstate improves the driving surface and will extend the life of I-5. 
    • Replacing expansion joints on the Interurban Avenue and Duwamish River bridges ensure those structures will remain open and operational.
  • Safety
    • Improving the interstate surface eliminates potholes and will help prevent future potholes and cracks. Eliminating the wheel ruts improves traction and will create a smoother, safer ride for drivers. 
    • Replacing the expansion joints on the Interurban Avenue and Duwamish River bridges reduces the chances that an aging expansion joint could fail, which would create a hazard for drivers and cause an emergency closure on I-5.
  • Economic
    • Replacing broken concrete panels, repaving and replacing expansion joints during a scheduled project reduces the need for emergency repairs, which are more expensive than scheduled repairs and cause additional congestion, particularly during peak commute hours. 
    • Repaving a 4-mile section of the interstate with asphalt instead of concrete is less expensive and less disruptive than replacing all of the concrete panels.


  • November 2016: Project was advertised for competitive bidding.
  • January 2017: Project was awarded to Gary Merlino Construction Co. Inc.
  • April 2017: Construction began.
  • Spring 2019: Construction is scheduled to be complete.


Financial Data for PIN 100506G, 100506H
Funding Source Amount ($ in thousands)
2003 Gas Tax (Nickel Funding) $35,264
2005 Gas Tax (TPA) $0
Pre-Existing Funds (PEF) $4,102
CWA $0
Total $39,366


Nicole Daniels
WSDOT Communications