Old, crumbling timber bridge felled; replaced by new concrete structure
SEATTLE – The cracked timber piles and failing wooden crossbeams that supported State Route 99 as it crossed over Spokane Street in Seattle are gone. They have been replaced by a stronger concrete structure with embankments of foam.
“Replacing this bridge was critical to preserving an important piece of our infrastructure,” said WSDOT Project Engineer Hien Trinh. “It’s a crucial section of the SR 99 corridor with more than 55 thousand trips over it every day, including daily commuters and freight haulers.”
The final push to reopen all lanes of traffic across the new bridge begins this week. Contractor crews working for the Washington State Department of Transportation will close both directions of SR 99 nightly to restripe and shift traffic. The work is weather dependent.
The new bridge is located just south of the West Seattle Bridge. The original overpass was built in 1959 using timber which rotted, split and crumbled with the passing decades and increasing traffic. The new overpass is supported by concrete and Geofoam blocks, which is a lightweight material that is not prone to settlement.
To keep traffic moving on SR 99 during the replacement project, crews from MidMountain Contractors, Inc. of Kirkland, Wash., demolished then rebuilt half of the bridge at a time.
For more information about the replacement of the old timber bridge, please visit the project website at www.wsdot.wa.gov/Projects/SR99/SpokaneStOvercrossing/