Alaskan Way Viaduct closes for two weeks starting April 29 as Bertha digs underneath

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SEATTLE -- The Alaskan Way Viaduct will close for about two weeks starting April 29 as Bertha, the SR 99 tunneling machine, digs underneath.

Bertha is about to start boring under the aging roadway, and the Washington State Department of Transportation says the long closure is a precaution in case something goes wrong.

WSDOT officials say this will be a 24/7 closure between South Spokane Street and the south end of the Battery Street Tunnel.

Ever since Bertha created that huge sinkhole along the waterfront earlier this year, WSDOT has been hovering over the tunnel contractor like a hawk, to make sure that all the problems have been fixed.  The state now says Bertha is ready to proceed under its first major structure, and is assuring the public that the viaduct will be OK.

“They have strengthened it using carbon fiber wrap and they have reinforced the foundation with micropiles,” said Todd Trepanier of WSDOT.  “Those preventative measures are adequate in our observation for them to be able to tunnel underneath the viaduct with any consequence.”

Given the recent viaduct traffic jam nightmare, from an overturned semi full of crab, officials say they are preparing the public now for the two-week closure.

“Traffic is going to be worse during the commute,” said Scott Kubly, director of the Seattle Department of Transportation.   “I would just encourage people that if they have alternate times that they can make their trip or alternate routes they can take or alternate locations they can go to, I would encourage them to do that.

About 90,000 cars using the viaduct each day.  Part of that will be absorbed by increased transit service and detours.

“When we closed the viaduct for nine days in 2011, we saw significant congestion on Seattle city streets and nearby highways,” said David Sowers, deputy administrator of the Alaskan Way Viaduct Replacement Program. “We’ll do everything we can to ease congestion, but unfortunately there’s no way to close a major highway without disrupting traffic.”

“We understand this closure will be a major inconvenience for many drivers, but we need their help to keep traffic moving,” said Sowers. “We will all get through this together if everyone starts the planning process now and adjusts their commutes.”

Commuters are encouraged to visit for the latest updates on the closure.

Tips from WSDOT:

  • Take the water taxi: King County Water Taxi is adding extra trips to and from Vashon Island to Colman Dock. There will be additional parking in West Seattle for the water taxi’s new, larger-capacity boat.
  • Work from home: Many employers offer options to work from home. Even teleworking one day a week will help ease congestion.
  • Consider biking or walking for the last part of a trip into downtown to avoid the heaviest congestion.

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