Webmaster
11-18-2008, 10:19 PM
By Susan Gilmore
Seattle Times staff reporter
The state Department of Transportation is closing the 80-year-old Highway 169 Green River Bridge near Black Diamond for at least six months because of safety concerns.
After reviewing extensive data gathered by electronic sensors in the landslide zone near the bridge in Black Diamond, DOT geotechnical engineers have determined the structure is vulnerable to significant land movement.
Crews will close the bridge tonight at 7 p.m. The bridge may remain closed for up to six months for significant long-term repairs.
"I can't emphasize enough that this closure is about safety," said Paula Hammond, Secretary of Transportation. "We will do what is necessary to keep the public safe and preserve the bridge."
Engineers say the soil supporting the bridge is showing unusual movement that could be aggravated by recent heavy rain. DOT officials are worried the soil may not be able to support one of the southern bridge piers. If the soil slides, the pier could move with it.
"At this point, it appears that last week's heavy rains saturated unstable soil under the bridge, and that soil is now moving. With the next storm set to hit Wednesday, we do not want to take any chances with safety," said Lorena Eng, regional administrator.
The long-term repairs will take place in two stages.
First, crews will remove excess water by clearing trenches, unplugging manholes and installing pumps to help drain water from the unstable hillside.
Second, crews will excavate the soil that is putting pressure on the bridge pier. They will dig out a section of roadbed 30 feet deep and 300 feet long just south of the bridge and replace it with lighter-weight material.
The work will cost about $10 million and will be done as an emergency contract.
The Green River Bridge carries an estimated 9,000 vehicles each day.
There are two detour routes: one for passenger vehicles and one for commercial trucks. Drivers can download the maps at: www.wsdot.wa.gov/Projects/SR169/GreenRiverRepair/Detour.htmDrivers can follow repair progress at:
www.wsdot.wa.gov/projects/sr169/greenriverrepair/
from: http://seattletimes.nwsource.com/html/localnews/2008407317_webbridgeclosure18m.html
Seattle Times staff reporter
The state Department of Transportation is closing the 80-year-old Highway 169 Green River Bridge near Black Diamond for at least six months because of safety concerns.
After reviewing extensive data gathered by electronic sensors in the landslide zone near the bridge in Black Diamond, DOT geotechnical engineers have determined the structure is vulnerable to significant land movement.
Crews will close the bridge tonight at 7 p.m. The bridge may remain closed for up to six months for significant long-term repairs.
"I can't emphasize enough that this closure is about safety," said Paula Hammond, Secretary of Transportation. "We will do what is necessary to keep the public safe and preserve the bridge."
Engineers say the soil supporting the bridge is showing unusual movement that could be aggravated by recent heavy rain. DOT officials are worried the soil may not be able to support one of the southern bridge piers. If the soil slides, the pier could move with it.
"At this point, it appears that last week's heavy rains saturated unstable soil under the bridge, and that soil is now moving. With the next storm set to hit Wednesday, we do not want to take any chances with safety," said Lorena Eng, regional administrator.
The long-term repairs will take place in two stages.
First, crews will remove excess water by clearing trenches, unplugging manholes and installing pumps to help drain water from the unstable hillside.
Second, crews will excavate the soil that is putting pressure on the bridge pier. They will dig out a section of roadbed 30 feet deep and 300 feet long just south of the bridge and replace it with lighter-weight material.
The work will cost about $10 million and will be done as an emergency contract.
The Green River Bridge carries an estimated 9,000 vehicles each day.
There are two detour routes: one for passenger vehicles and one for commercial trucks. Drivers can download the maps at: www.wsdot.wa.gov/Projects/SR169/GreenRiverRepair/Detour.htmDrivers can follow repair progress at:
www.wsdot.wa.gov/projects/sr169/greenriverrepair/
from: http://seattletimes.nwsource.com/html/localnews/2008407317_webbridgeclosure18m.html