The Washington State Department of Transportation (WSDOT) says that once the new SR 99 tunnel opens, which is expected in early February 2019, demolition of the Alaskan Way Viaduct will begin, Seattle Curbed reports.
Kiewit Infrastructure West Co. has been selected as the contractor for the $93.7 million demolition project, which will also include reconnecting several streets to the tunnel and replacing a pedestrian bridge.
“What makes this unique, the close proximity of the buildings, the massive grid of utilities that we’re going to be protecting,” says Dan Hemenway, project manager for Kiewit Infrastructure West Co., who is overseeing the demolition of the viaduct. “Our goal is to have as little impact as possible. All that’s a big challenge, and we are well prepared for it.”
According to a report by the Seattle Times, demolition will start with the upper road deck and work downward. Tunnel segments will be trucked to Terminal 25, where the rebar will be removed and the concrete crushed to fill in the Battery Street Tunnel.
After each segment of road deck is removed, crews will remove girders, crossbeams, and then columns. Demolition of the viaduct itself is estimated to take approximately six months, but the decommissioning of old roadways and filling in of the Battery Street Tunnel could take up to two years.