Testing on Seattle’s tunnel boring machine was stopped temporarily due to a broken arm.
The Seattle Times reports a soil-mixing arm inside Bertha broke during tests on Wednesday. It was apparently a quick fix, however, as crews resumed filling the pit the machine is currently sitting in with sand on Thursday.
Crews are testing the machine as they prepare to get it moving again.
Seattle Tunnel Partners are still shooting to get Bertha moving again by Dec. 23. The hope is to drill about 14.5 feet and install new tunnel rings before workers go on a 10-day vacation. Bertha could begin drilling by Monday.
Seattle Tunnel Partners project manager Chris Dixon told state lawmakers on Thursday that moving the machine through the sand and soil of the repair pit will be the last phase of testing, KIRO 7 reports. Dixon said the machine could break through the wall of the repair pit and continue on its journey after the break.
The $2 billion tunnel project that will eventually replace the Alaskan Way Viaduct is more than two years behind schedule. The tunnel’s opening date has been pushed back to April 2018.
Bertha tunneled 1,023 feet before overheating underground. The entire tunnel will be 1.7 miles.
Under the current schedule for Bertha, which the state will not verify, Bertha will advance about 450 feet in January. It will be inspected before tunneling beneath the viaduct, which the Washington State Department of Transportation expects to close for up to two weeks.