Plans are on track for construction work on Seattle’s Alaskan Way tunnel to commence in mid-2013. The massive TBM that will drive the tunnel has been tested in Japan by its manufacturer 233 Hitachi and is now being shipped to the US. The TBM has a 17.5m diameter cutting head, making it the largest machine ever constructed. This is bigger even than the 2592 Herrenknecht machine with its 15.62m diameter cutting head built for the Bologna-Florence highway tunnel project in Italy.
The new Hitachi TBM has been disassembled into different sections for transportation to the US and is expected to arrive at the end of March 2013. The launch area for the TBM is being prepared at present and the Alaskan Way Viaduct Replacement Tunnel is scheduled to open in late 2015. When complete the 3.2km tunnel will carry State Route 99 under Downtown Seattle from the SoDo neighborhood to South Lake Union in the north.914 Washington State Department of Transportation’s US$1.35 billion project will replace the existing 1950s vintage viaduct, which was damaged in an earthquake in 2001. The tunnel will run at a depth of up to 61m beneath the city and will carry 110,000 vehicles/day while its construction also frees up the waterfront area for redevelopment.
The new Hitachi TBM has been disassembled into different sections for transportation to the US and is expected to arrive at the end of March 2013. The launch area for the TBM is being prepared at present and the Alaskan Way Viaduct Replacement Tunnel is scheduled to open in late 2015. When complete the 3.2km tunnel will carry State Route 99 under Downtown Seattle from the SoDo neighborhood to South Lake Union in the north.
