Plan ahead: Weekend closure of northbound I-5 in Seattle for girder setting scheduled for May 19-21

I-5 express lanes will close for part of weekend

SEATTLE – Travelers in downtown Seattle will need to prepare for weekend-long closures of northbound Interstate 5 and the I-5 express lanes starting Friday, May 19. The closures are needed to place girders over the freeway for a new flyover ramp connecting State Route 520 to the express lanes, marking a significant milestone for this project.

  • 10 p.m. Friday, May 19 to 10 a.m. Saturday, May 20, people traveling north of downtown Seattle will need to use the express lanes or exit to SR 520.
  • The express lanes will close at 11 a.m. Saturday, May 20, and remain closed until 10 a.m. Sunday, May 21.
  • A full breakdown of the schedule is available on the project webpage.

Detours in place

During this closure, drivers who remain on northbound I-5 after Mercer Street will detour at eastbound SR 520 and take the Montlake Boulevard exit. From there, drivers will use Montlake Boulevard to turn around and enter westbound SR 520 before rejoining northbound I-5 just past the work zone. Uniformed police officers will help guide traffic through the detour. People who continue past the Montlake Boulevard exit on eastbound SR 520 will need to pay the SR 520 bridge toll.

What's happening

Walsh Construction Co. II crews working for the Washington State Department of Transportation will set and assemble steel bridge girders above northbound I-5 and the express lanes beginning at 10 p.m. Friday, May 19 through 10 a.m. Sunday, May 21.

The process to erect the girders involves using two cranes that will lift the girders into position and assemble them in midair. Crews will then set and bolt them to the newly constructed piers and crossbeams. Following this closure, crews will tighten the entire structure into its final setting.

WSDOT is using steel bridge girders because of the curve the new flyover ramp will have. This is a unique situation as normally cast-in-place or precast concrete girders are used in other projects.

Closure schedules

This closure involves times where northbound I-5 and the express lanes alternate between being closed, reduced to single or double lanes, or open.

People should plan ahead for travel delays and consider avoiding the area if possible. Construction can be unpredictable, and any delays related to this work will be shared immediately by WSDOT.

Stay up to date

People can get real-time traffic information from the WSDOT app, following social media, and learn more by visiting the SR 520 Construction Corner. People can also call or text the 24-hour hotline at 206-316-2559.

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