Work to begin on unstable Green River Bridge; $15M in federal money to fund 6-month repair effort

December 5, 2008 7:01 pm
WSDOT geotechnical engineer Tom Badger explained to the media on Nov. 18 how the soil was moving beneath the State Route 169 Kummer Bridge support.
WSDOT geotechnical engineer Tom Badger explained to the media on Nov. 18 how the soil was moving beneath the State Route 169 Kummer Bridge support.

Washington State Department of Transportation contractors will begin emergency repair work near the State Route 169 Green River Bridge on Saturday.

Tri-State Construction crews will spend the next 30 days excavating a large section of road just south of the bridge, also called the Kummer Bridge.

The bridge that links Black Diamond and Enumclaw in southeast King County closed to all traffic on Nov. 18 after geotechnical engineers noticed small, but potentially dangerous movement in the soil that supports the southern-most pier.

Secretary of Transportation Paula Hammond agreed to close the bridge saying driver safety is WSDOT’s first priority.

Since Nov. 18, WSDOT engineers have put together a two-part plan to repair the bridge from the pressure of the landslide.

“A large ancient landslide to the northeast is slowly pushing the ground that supports the southern pier, causing the ground to shift,” said Russ East, assistant regional administrator. “We need to relieve that pressure to stop the slide.”

Phase one begins at 7 a.m. Saturday when crews begin tearing up the asphalt and digging out an area that measures 25 feet deep by 200 feet long by 80 feet wide. Crews will work 10-hour shifts Saturday and Sunday then shift to 20-hour days on Monday. They will work around the clock until Christmas to complete the excavation.

“The work will be noisy and drivers can expect to see 1,500 truckloads of material removed from the area,” said Messay Shiferaw, WSDOT construction engineer. “We will refill the space with lighter material that can better withstand the pressure of the slide.”

Phase two begins in February when crews install new walls to protect the south pier. Officials expect to reopen the current bridge to traffic by June 2009.

While engineers have been watching the area for years, the problem turned into an emergency in early November when heavy rain pummeled the area. Gov. Chris Gregoire signed a disaster declaration Nov. 26 after the storm, which allowed WSDOT to apply for and receive federal emergency funding from the Federal Highway Administration. The estimated cost for repairs is $15 million.

While drafting a repair plan, WSDOT staff has worked with the King County Roads Division to designate and monitor detour routes. They also worked with WSDOT designers to create informational signs to let drivers know Black Diamond, Enumclaw and unincorporated King County are open for business.

“It’s been very tough for businesses out there,” East said. “The national economy is awful and this closure has made it worse. We really wish there were something more we could do to help folks. We just want to remind drivers that you can really help by visiting those local businesses.”

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For the most recent information about the closure, go to: www.wsdot.wa.gov/projects/sr169/greenriverrepair/