Seattle Tunnel Partners has successfully hoisted the first piece of the 57.5-ft diameter SR 99 tunneling machine to the surface for repairs. Crews lifted the machine’s 270-ton upper body to the surface on Thursday, March 18.
Three more pieces of the machine will be removed from the pit as part of STP’s repair plan (see narrated video for additional detail). Up next, crews will lift the upper right and upper left sections of the machine – both of which weigh less than 100 tons. The final lift will bring to the surface Bertha’s massive cutterhead and main drive unit, which weigh a combined 2,000 tons.
The SR 99 project has been stalled since December 2013 due to mechanical issues with the TBM, which had mined 1,000 ft before being stopped. The owner, Washington State Department of Transportation, anticipates opening of the tunnel in in the second half of 2017.