Bertha is back on the move under Seattle’s waterfront
After a two-week break, Bertha is tunneling below Seattle’s waterfront again.
The tunnel machine was at a standstill 170 feet below First Avenue and Union Street for maintenance to the cutterhead. The Washington State Department of Transportation says crews replaced a total of 14 large cutting tools during the stoppage. Bertha is moving through more sand and gravel now, which can be harder on the tools than clay.
The tunnel contractor will continue to keep an eye on the tools as tunneling resumes. Crews are planning another stop — location to be determined — for more hyperbaric maintenance.
Bertha has tunneled more than 4,135 feet and is near the halfway point of the 9,270-foot-long journey.
Follow the progress here.