Alaskan Way Viaduct
replacement program: SR99 bored tunnel
The Port of Seattle depends on the Alaskan Way Viaduct for freight mobility, port facility access, and regional mobility. While our container trucks don’t travel on the Viaduct, it still carries over 100,000 vehicles daily that otherwise would be using the Duwamish area streets and conflicting with freight and rail lines.
Many people use the viaduct to access the Pier 66 Central Waterfront complex and Cruise Terminal, Pier 69, Terminal 91, Sea-Tac Airport and the port marinas. Also, the viaduct is key to the regional highway system, carrying 25% of the north-south traffic through the downtown area.
Following the Nisqually earthquake of February 2001, the state and city realized that the viaduct (built in 1953) was at risk from another major seismic event and would have to be replaced.
In January 2009, Governor Christine Gregoire, Mayor Greg Nickels, and County Executive Ron Sims announced a Bored Tunnel Hybrid as the preferred alternative to carry forward for further study. The bored tunnel option was selected, in part, because it was the only approach that would allow SR 99 to remain open for the majority of construction.
Conceptual drawing. Click image to enlarge
In August 2013, the Port and the Washington State Department of Transportation (WSDOT) entered into an agreement for a port contribution of $281 million so that the replacement of the viaduct achieves the best balance among retaining and creating jobs, sustaining regional economic vitality, and benefiting the environment.
The tunnel is expected to open in 2019, dependent upon the contractor's rate of progress.