Eastbound State Route 518 near Sea-Tac International Airport will close for two consecutive weekends in mid-July to replace a damaged bridge girder, WSDOT announced this week.

This repair also requires a 14-week closure of the 24th Avenue South bridge over SR 518, beginning Wednesday, July 5, 2023.

During the project, contractor crews working for the Washington State Department of Transportation will replace a bridge girder on the 24th Avenue South bridge that was struck and severely damaged in 2020 by an over-height vehicle travelling eastbound on SR 518.

The bridge connects Sea-Tac International Airport on the south side of SR 518 with a large employee parking lot on the north side. Other businesses and travelers in the area also use the overpass. Signed detours will be in place during the closures. Travelers should plan ahead and allow extra travel time in the area during this work.

Eastbound SR 518 closure

All lanes of eastbound SR 518 will close for two consecutive weekends between SR 509 and SR 99/International Boulevard, as crews remove the damaged girder one weekend and replace it the next.

  • The first closure will begin at 9 p.m. Friday, July 14, and last until 5 a.m. Monday, July 17. The left lane of westbound SR 518 also will close during those times.
  • The second closure will begin at 9 p.m. Friday, July 21, and last until 5 a.m. Monday, July 24.

During the weekend closures, eastbound SR 518 traffic will detour using Des Moines Memorial Drive, South 156th Way, South 154th Street and SR 99/International Boulevard to the eastbound SR 518 on-ramp.

Long-term 24th Avenue South bridge closure

The 24th Avenue South bridge will close in both directions throughout the expected 14-week project. This long-term closure begins at 9 p.m. Wednesday, July 5.

A detour will be in place using South 152nd Street, SR 99 and South 154th Avenue. One shoulder along the bridge will remain open for pedestrians, people on bicycles and other rollers to cross over SR 518.

Real-time travel information is available via the WSDOT mobile app, the real-time travel map, or by following the WSDOT Traffic Twitter account.