Northbound SR 99 First Avenue South Bridge closing for emergency deck repairs starting Friday, May 8

SEATTLE - The Washington State Department of Transportation will begin a second phase of emergency repairs to the northbound State Route 99 First Avenue South Bridge. These repairs will begin at 9 p.m. Friday, May 8, and will be followed by a series of weekend and weeknight bridge closures to install new steel grid deck panels.

Closure details

Up to three lanes will close across the northbound SR 99 First Avenue South Bridge starting at 9 p.m. each night beginning as early as Monday, May 4, through Friday morning, May 8, to set up a work zone. All lanes will reopen across the bridge each morning by 5 a.m.

All northbound lanes across the SR 99 First Avenue South Bridge will close for bridge repairs:

• From 10 p.m. Friday, May 8, until 5 a.m. Monday, May 11.
• From 10 p.m. to 5 a.m. each night Monday, May 11, until Friday morning, May 15 and Monday, May 18, until Friday morning, May 22.

Additional night or weekend closures are possible depending on the pace of bridge repairs.

"Our primary focus right now is restoring the northbound SR 99 First Avenue South Bridge to its full capacity for the 50,000 people who cross it each day," said WSDOT Northwest Region Administrator Brian Nielsen.

What people can expect

Signed detours will guide northbound SR 509/SR 99 traffic around the bridge closure. Congestion is likely and people should use northbound Interstate 5 or other alternate routes during construction.

The First Avenue South Bridge Trail also will close during these times. Accessible shuttle vans operating from signed locations north and south of the bridge will carry pedestrians and cyclists around the work zone.

Maritime traffic under the First Avenue South Bridge will be restricted during construction. Vessels requiring the bridge to open must provide 24-hour notice and confirm their arrival two hours beforehand. These U.S. Coast Guard restrictions will remain in place through June 30, 2026.

Three-phase bridge repair strategy

WSDOT developed a three-phase repair plan after inspectors identified cracks in the steel grid bridge deck in February 2026.

WSDOT crews completed Phase 1 repairs in March 2026 during a five-day closure of the bridge. These initial repairs allowed all northbound lanes to reopen across the bridge at a temporary reduced speed limit.

Phase 2 repairs begin Friday night, May 8, and last roughly 30 days. Contractor crews working for WSDOT will replace nine 28-by-9-foot steel deck panels. Once complete, all northbound lanes across the SR 99 First Avenue South Bridge will reopen at normal speeds.

The emergency contract for Phase 2 repairs was awarded to C.A. Carey of Issaquah. The estimated cost is $1.3 million.

Phase 3 repairs will replace remaining steel grid deck plates on the northbound SR 99 First Avenue South Bridge. This work is in the design phase and is currently scheduled for the 2027 construction season.

About the First Avenue South Bridge

The First Avenue South Bridge is a moveable, double-leaf bascule bridge spanning the Duwamish River between Seattle's Georgetown and South Park neighborhoods. During its last full inspection, the bridge was rated in fair condition.

The First Avenue South Bridge is part of a statewide bridge system with infrastructure operating beyond its intended service life. WSDOT often extends the life of these bridges through targeted repairs while larger preservation projects are being developed. This approach allows structures to remain in service, but it also means that when conditions change, crews must act quickly and sometimes close lanes or structures in the interest of public safety.

Each time WSDOT must take this action highlights the critical need for investment in the preservation of our transportation system.

Plan ahead

Real-time travel information is available via the WSDOT mobile app, the WSDOT travel map or by signing up for WSDOT's email updates.