Bertha, the tunneling machine working on the Alaskan Way Viaduct in Seattle, reached a planned maintenance stop on March 12, after successfully mining almost 300 feet during the past three weeks, according to Seattle Tunnel Partners (STP).The company says the tunnel boring machine functioned within required operating parameters and has now mined a total of 1,560 feet.STP will spend up to one month inspecting the machine and performing planned maintenance. Work includes performing hyperbaric interventions, inspecting the cutterhead, main drive unit and screw conveyor, replacing cutting tools, and extending the conveyor belt and the high voltage cable.Engineering Students Honored at
