Tunnel-boring machine Bertha has reached the maintenance stop known as “Safe Haven 3,” just before its spring dive underneath the Alaskan Way Viaduct.
The giant drill traveled about 300 feet in the past three weeks, the Washington State Department of Transportation said in an update Monday afternoon.
This haven is a concrete box that was built in 2013, so that crews could reach the giant cutting face, to perform repairs and replace drill teeth.
