On December 10, California, US-based civil and building construction company Tutor Perini Corporation announced that it has been named by the US' Washington Department of Transportation as part of the winning team for the SR99 Bored Tunnel project to be constructed by Seattle Tunnel Partners, a joint venture of Dragados USA (55 percent) and Tutor Perini (45 percent). The initial contract value is expected to be approximately $1.09 billion.
The project, also known as the Alaskan Way Viaduct Replacement project, will involve the construction of approximately 12,500 feet of new roadway, of which 9,273 feet will be constructed using an earth pressure balance tunnel boring machine. At the time of construction, this will be the largest tunnel boring machine construction in the world.
When constructed, the tunnel will allow two lanes of traffic in each direction in a stacked configuration with the North-bound lanes on the top and the South-bound lanes on the bottom. The stacked configuration will then gradually diverge and rise back to existing ground traffic configurations through the North and South approach roadways.
The contract award and initial notice to proceed are scheduled for January 4, 2011. The second notice to proceed for construction is expected to be issued in August 2011. Final completion and traffic through the tunnel is scheduled for December 2015.