The Washington State Department of Transportation (WSDOT) has chosen Jacobs Associates to provide construction management (CM) support for the $1.35 billion SR 99 Tunnel Project in Seattle. This 1.7-mile long tunnel will be built by the world’s largest diameter tunnel boring machine (TBM). The tunnel is part of a program to replace the seismically vulnerable SR 99 Alaskan Way Viaduct, a double-deck structure that for the past half century has spanned the downtown waterfront.
Jacobs Associates’ services prior to tunnel construction include reviewing and commenting on design submittals, schedule analysis, tunnel systems integration support and assistance with geotechnical monitoring. Jacobs Associates currently provides a resident engineer collocated with WSDOT staff, and a schedule engineer supporting schedule submittal reviews and impact assessment. Construction on the tunnel project began in August 2011, and tunnel boring is slated to start in mid-2013. Subconsultants Parsons Brinckerhoff and Heery International are proposed to augment Jacobs Associates’ tunnel inspection staff and provide specialized technical support during future construction.
WSDOT is working closely with its design-build contractor, Seattle Tunnel Partners, a joint venture of Dragados USA and Tutor Perini Corp., which includes local firms Frank Coluccio Construction, Mowat Construction and HNTB Corp. The team has selected Hitachi Zosen Corp. to supply the project’s TBM.
The tunnel will open to traffic in late 2015, clearing the way for viaduct demolition and a new era for the SR 99 corridor and Seattle’s waterfront.