Alaskan Way Viaduct and Seawall Replacement Program

The Alaskan Way Viaduct & Seawall Replacement Program will replace the earthquake-damaged State Route 99 Alaskan Way Viaduct, an elevated highway structure supporting more than 100,000 vehicle trips per day, and the seawall, which is deteriorating and does not meet current seismic or roadway design standards. The viaduct is located in an important and sensitive location— an area of substantial and continuous economic and tourist activity, as well as the site of the Washington State Ferry’s water access.

WSDOT, the City of Seattle, the Port of Seattle, and the Federal Highway Administration have partnered to develop and construct a replacement that will meet current standards and improve long-term mobility. The new tunnel, which will be approximately two miles long with diameter of 57 ft, will be constructed using a tunnel boring machine (TBM). Inside, the viaduct will include a two-level stacked roadway and state-of-the-art tunnel systems. The program team is developing environmental documentation with a target for the tunnel being opened to traffic in late 2015, and all construction completed along the Central Waterfront no later than 2020.

HMM is Project Management Assistant Consultant (PMAC), providing program and design management and related technical and construction management services, including program/design management support; independent oversight; risk, value engineering and constructability review; change control and configuration management support; construction management; project controls and reporting; intergovernmental agreements; document management; and budgeting/funding management support.

HMM's first major tasks included developing an FHWA-mandated project management plan (PMP) for the project, and a PMP template to be used by the agency on all other WSDOT mega projects; design review of deliverables; and program management process development using best-of-breed software tools. WSDOT anticipates that it will retain the PMAC throughout the program from start to finish, including design through tunnel construction.