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SR 99 Alaskan Way Viaduct to close this weekend, May 18-21

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Date:  Tuesday, May 15, 2012

Contact: Travis Phelps, Alaskan Way Viaduct Replacement Program, (cell) 206-462-0554 (Seattle)

Expect traffic delays in downtown Seattle during closure

SEATTLE – Crews will close the State Route 99 Alaskan Way Viaduct this weekend to continue reinforcing a two-block section of the structure located above the route of the future SR 99 tunnel.

Both directions of SR 99 between the north end of the Battery Street Tunnel and the West Seattle Bridge will close from 11 p.m. Friday, May 18, to 5 a.m. Monday, May 21.

Drivers should plan for increased congestion in and near downtown Seattle during the closures, and consider leaving early, carpooling or taking transit. Up-to-the-minute traffic information is available at and via the Washington State Department of Transportation’s voice-activated driver information line, 511.

During the closure crews will wrap a protective reinforcing fiber on the concrete beams of the viaduct’s lower deck between South Washington and Columbia streets in Pioneer Square. This spring crews repaired and smoothed the concrete to provide a suitable surface for the protective fiber.

“It’s like wrapping an injured ankle,” said Matt Preedy, WSDOT Alaskan Way Viaduct Replacement Program deputy administrator. “Protecting this section of the viaduct is important because crews will drive the tunnel boring machine beneath it in late 2013.”

Currently being manufactured in Japan, the machine is designed specifically for the soil and groundwater conditions along the tunnel alignment. Although tunneling crews do not anticipate significant levels of ground settlement, they are monitoring structures above and near the tunnel route as a precaution.

In addition to the reinforcement work, tunnel crews are building underground walls beneath the viaduct’s foundations to further protect it during tunneling.

For more information on the Alaskan Way Viaduct Replacement program, visit


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