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Thursday, October 13, 2011
KaDeena Yerkan, Alaskan Way Viaduct Replacement Program, 206-805-2846; 206-795-1876 (Seattle)
Huge machine will tunnel beneath Seattle beginning in 2013
SEATTLE – Hitachi Zosen Corp. of Japan cemented its role in the SR 99 Tunnel Project on Wednesday, signing a contract with Seattle Tunnel Partners to supply the machine that will tunnel beneath downtown Seattle.
“Signing this contract gets us one step closer to taking down the vulnerable Alaskan Way Viaduct,” said Gov. Chris Gregoire. “This state-of-the-art technology allows us to keep SR 99 – and the region’s economy – open for business during construction to replace this critical state highway.”
In July, Hitachi signed a letter of intent with Seattle Tunnel Partners, the Washington State Department of Transportation’s design-build contractor for the tunnel project. The letter of intent allowed the Japanese firm to begin preliminary design of the machine this summer. WSDOT will pay Seattle Tunnel Partners approximately $80 million for the machine, an amount included in the tunnel project’s $1.35 billion contract.
By signing the contract on Wednesday, Hitachi now can complete design of the 57.5-foot-diameter machine, which will be barged to Seattle and assembled at the south end of downtown in early 2013. The boring machine will be launched from a pit near the Seattle sports stadiums where crews will begin demolishing the southern half of the viaduct next week. Demolition will require closure of the viaduct for nine days, beginning on Oct. 21.
“This will be a truly amazing machine,” state Transportation Secretary Paula Hammond said. “At nearly 60 feet in diameter and more than 300 feet long, it will be about the same size as some of Washington State Ferries’ largest vessels.”
Tunnel boring machines are like mobile construction sites, Seattle Tunnel Partners Project Manager Chris Dixon said.
“Even though the public can’t see them, crews will be hard at work underground,” Dixon said. “At any given time there will be up to 40 workers inside operating the machine, monitoring ground conditions, maintaining equipment and working to ensure that tunneling goes smoothly.”
Later this month, crews will begin utility relocation and other preliminary tunnel work. Excavation of the tunnel launch pit will begin next year, followed by tunnel boring in mid-2013. The tunnel is scheduled to open to drivers in late 2015.
Hitachi was selected ahead of three other firms based on overall technical requirements, support capabilities, price and schedule. Based in Osaka, Japan, the firm has successfully built more than 1,300 tunnel boring machines, a number of them for large-diameter tunnel projects. They are currently supplying the tunnel boring machines for Sound Transit’s Capitol Hill Station to Pine Street segment and the Bay Tunnel near San Francisco, Calif.
For more information on the Alaskan Way Viaduct and Seawall Replacement Program, visit www.alaskanwayviaduct.org/.
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