Success in Seattle as TBM holes through Mar 2012
Paula Wallis, TunnelTalk

TBM breakthrough sequence, March 21, 2012

Contractor Traylor Bros/Frontier-Kemper (TFK) JV is celebrating breakthrough of one of its two Herrenknecht EPBMs on the University Link (U-Link) light rail extension in Seattle, Washington.

Capitol Hill TBM breakthrough

The 6.4m diameter TBM, Togo, pushed through the wall into the Capitol Hill station site early Wednesday morning, March 21, 2012, completing its 3.2km drive from the University of Washington. The machine emerged within 3mm of its target.
"Every turn of the cutterhead that emerged on Capitol Hill has put us closer to a fast train service between downtown Seattle and the University of Washington," said Sound Transit Board Chair and Pierce County Executive Pat McCarthy. "The Board thanks and congratulates the talented companies and workers that are well on the way to delivering this long-awaited project."
"Overall, the $1.9 billion U-Link project is about halfway complete," said Sound Transit spokesperson Bruce Gray.

Fig 1. Seattle's U-Link contracts

"TFK crews working on this contract have done an outstanding job delivering TBM Togo, and soon the parallel drive TBM Balto, to their destinations. They are about three months ahead of contract schedule for this portion of the work."
TKF JV, which holds contract U220, launched the TBM from the University of Washington site near Husky Stadium in May 2011 (Fig 1). The second TBM, Balto, is expected to breakthrough in April.
Meanwhile on a separate contract (U230), the Jay Dee/Coluccio/Michaels JV is operating a third EPBM manufactured by Hitachi Zosen to drive the second of two 1.1km running tunnels from the Capitol Hill station box to a reception shaft near the existing Downtown Transit Tunnel. The machine is expected to hole through in June. It completed its first drive in November 2011 following a launch five months earlier.
With major tunneling work wrapping up, contractors have begun mining 20 cross passages between the north and southbound tunnels. The civil works for the project are expected to be completed by the end of 2012.
Seattle LRT breakthroughs - TunnelTalk, November 2011
TBMs launch on Seattle's U-Link - TunnelTalk, May 2011

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