Project Title & Location

SR 99 - Alaskan Way Viaduct and Seawall Replacement Project

Project Description
The existing seismically vulnerable Alaskan Way Viaduct and Seawall are both at the end of their useful life and at risk of sudden and catastrophic failure in an earthquake. The cost to replace in-kind this seismically vulnerable structure is between $2.0 and $2.4 billion. (This figure does not include the cost of replacing the seawall or work north of Battery Street tunnel. Necessary to protect public safety and maintain the transportation corridor.

Contractor/Consultant
Parsons Brinckerhoff Quade & Douglas is the prime design consultant. Hatch Mott MacDonald is the Program Management Assistant Consultant

Recent Progress

During the Current Quarter, the Team responded to recommendations made by the Expert Review Panel. The Quarterly inspection of the viaduct revealed that one section has settled an additional 1/4".   The video simulations were produced for the Elevated Structure and the Tunnel alternatives.   Finished the relocation of PSE's 12 inch gas main.  Work continues on the Construction Traffic Managment Plan. 

Design Construction Impacts

Utilities construction is currently scheduled to begin Summer-2008, which will impact traffic on local city streets. Roadway construction is planned to begin Winter-2009. Ramp and lane closures on SR 99 are likely to begin mid to late 2010.

Environmental Impacts / Compliance

The Biological Assessment was submitted to USF&W and NMFS on October 13, 2006.  The comment period for the SDEIS closed in September 2006.  The AWV Project Team is collating and answering comments received. Work has begun on developing a mitigation strategy for the final EIS.

Impacts to Traffic

The team continues to analyze the trade offs between construction duration, cost, and maintenance of traffic, and impact to the community.

Planned vs. Actual Expenditures
(Total Project Cost)

Nickel funds included in above costs

2005 Transportation Partnership Account