Dragados and Tutor Perini sign Alaskan Way design-build contract

7 January 2011

Seattle Tunnel Partners signed a USD 1.35bn contract with the Washington State Department of Transportation (WSDOT) on Thursday to design and build the a two-level, 1.7-mile (2.7km) bored tunnel that will replaced the Alaskan Way Viaduct in Seattle.

The joint venture of Dragados USA and Tutor Perini, with Frank Coluccio Construction, Mowat Construction and HNTB Corp, was one of two teams that competed for the design-build contract, which included tunnel boring, mitigation for tunnel settlement, construction of tunnel portals, building the road within the tunnel and constructing two operations buildings.

In addition to Seattle Tunnel Partners’ proposal price of just under USD 1.09bn, the contract includes allowances for inflation, bonding and insurance requirements. Utility work reimbursed by the city is also included in the contract, bringing the total contract amount to USD 1.35bn, with up to USD 70M in incentives. ??

“With this contract, we are confident that the tunnel will be built within budget and delivered on time,” Washington transportation secretary Paula Hammond said. “More than 90 percent of the design-build work will be performed for a fixed price.”

WSDOT said Seattle Tunnel Partners will continue preliminary design work in February. If tunnel plans are approved following the project’s environmental review, expected this summer, the agency will direct the design-build team to begin final design and construction of the bored tunnel.

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Total cost of the proposed bored tunnel is estimated to be USD 1.96bn. This includes design, right-of-way acquisition, construction management, and more than USD 200M set aside for risk. The total estimate includes separate, future construction contracts for roadway connections at the north and south ends of the tunnel. ?