Hitachi Zosen TBM to excavate Alaskan Way tunnel

Seattle Tunnel Partners (STP) announced Monday it has chosen Japan’s Hitachi Zosen to supply the 58ft (17.7m) diameter TBM that will bore the tunnel replacing the Alaskan Way Viaduct.

Hitachi Zosen will be responsible for designing, manufacturing, assembling, testing and commissioning the machine as well as training STP personnel.

Herrenknecht (Germany), Hitachi Zosen (Japan), Kawasaki-Seli (Japan, Italy), and Robbins-Mitsubishi (United States, Japan) submitted boring machine proposals on May 31.

A press release issue by Washington State Department of Transportation’s (WSDOT) said Hitachi Zosen was the “best value manufacturer based on overall technical requirements, support capabilities, price and schedule.”

STP, the design-build contractor joint venture of Dragados USA and Tutor Perini, had met with all of the manufacturers numerous times during the evaluation, and issued a letter of intent to Hitachi Zosen on July 15, which allows them to begin preliminary design until the project receives federal environmental approval next month.

Once approval is issued, WSDOT will direct the contractor to proceed with final design and construction, and the design-build team will execute a contract with Hitachi Zosen to design and manufacture the boring machine.