WSDOT Takes Major Step Toward Alaskan Way Viaduct Demolition

SEATTLE, WA - A major milestone toward the completion of SR 99 reconstruction in downtown Seattle happened Wednesday. WSDOT announced it has hired Kiewit Infrastructure West Co. to tear down the Alaskan Way Viaduct.

Drilling a large tunnel underneath Seattle was a major engineering challenge - but the viaduct demolition is going to be tricky, too.

Crews will have to remove utilities and maintain access to the ferry dock - not to mention being careful not to bump into apartment and office buildings that are practically on top of the viaduct.

"In some places, the viaduct is built within inches of buildings," WSDOT Deputy Administrator Brian Nelson said.

Access to Alaskan Way - the surface street below the viaduct - will continue, with WSDOT promising at least one lane open in each direction throughout the demolition. The road will be moved from underneath the viaduct west toward the waterfront.

The majority of the demolition will happen in 2019 and may take up to nine months. In addition to destroying the viaduct, Kiewit will fill in the Battery Street Tunnel and reconnect surface streets to SR 99. The entire demolition will cost about $90 million.

The new SR 99 tunnel should open by fall, according to WSDOT.

File photo by Neal McNamara/Patch