Local Information

Repairs mean overnight closures, lane reductions on southbound SR 99 bridge in Seattle starting March 5

Tuesday, February 16, 2021 - 13:42

Update: Please note the work is now scheduled to begin Friday, March 5 and the bridge will be reduced to two lanes for just five days. These changes are reflected in the text below.

Tom Pearce, communications, 206-440-4696

Crews will repair bearings, steel supports during lane reduction

SEATTLE – Lane reductions on the southbound State Route 99 Duwamish River Bridge, also known as the First Avenue South bridge, will begin the night of Friday, March 5.

The southbound bridge will be closed from 9 p.m. March 5 to 6 a.m. March 6. This will be the first of four overnight closures during the two-week project for contractor crews working for the Washington State Department of Transportation to repair bearing pads and steel beams that support the structure.

The southbound bridge also will be reduced to two lanes March 10-15. This will overlap with full overnight closures on March 14 and 15. Work does not affect the northbound bridge.

With the West Seattle Bridge closed, WSDOT Project Engineer Mike Askarian said people who use the SR 99 bridge to reach West Seattle, Burien, SeaTac and other locations will need to use alternative routes or allow extra travel time.

“There is never a good time to do this sort of work, but these repairs are necessary to keep the bridge in good condition,” Askarian said. “We have been watching the bearings that support the bridge for a couple of years. Last fall we found they had worn to the point where they need to be replaced. This is a challenging time for travelers with the West Seattle bridge closed, but doing this work now will prevent future damage to the bridge.”

WSDOT is working closely with the Seattle Department of Transportation to provide early notification about this project and trip-planning resources to keep traffic moving efficiently while reducing congestion, pollution and speeding.

What travelers can expect
The work will require numerous closures and lane reductions.

  • Two full closures, 9 p.m. to 6 a.m. March 5 and 6.
  • Two full closures, 9 p.m. to 5 a.m. March 14 and 15.
  • Two lanes closed 24 hours a day starting at noon, March 10 through noon March 15.

Travelers should consider avoiding the bridge, particularly during afternoon peak travel hours.  Alternative routes include East Marginal Way South Bridge, the Tukwila International Boulevard Bridge, Interstate 5 and the South Park Bridge.

Bridge work
During the lane reductions, crews from Massana Construction Inc. will replace bearing pads and repair some of the steel that supports the bridge. The bearing pads – masonry pads that the girder rests on – were part of the initial construction when the southbound SR 99 Duwamish River Bridge opened in 1996. These pads are worn out and need to be replaced. The pads allow precise setting of the elevation of the bridge’s roadway.

During the first two overnight closures, crews will lift the bridge deck a small amount to access, remove, and begin replacement of the bearing pads. When work is complete, crews will use the final two closures to complete the bridge repair work.

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