Bertha TBM Begins Moving

WSDOT reported that Bertha has slowly began moving again. It must tunnel through 20 feet of unreinforced concrete with its broken seal to break through into the rescue shaft. Once that happens, the repairs to her cutterhead can commence. The Seattle Tunnel Partners predict Bertha will overheat, as she did before stopping for repairs. If that occurs, they will stop tunneling to wait for the machine to cool before continuing. STP crews also chipped away at a Bertha-sized cut-out in the access shaft to make for a cleaner breakthrough. See video below. [Source: WSDOT and WSDOT YouTube Channel. Image: YouTube]