Daily archives: 2 June, 2016


View from a drone inside a tunnel executed by Bertha

wsdot View from a drone inside the SR 99 tunnel, executed by Bertha. Bertha, also known as Big Bertha, is a 57-foot-diameter (17.4 m) tunnel boring machine built specifically for the Washington State Department of Transportation’s (WSDOT) Alaskan Way Viaduct replacement tunnel project in Seattle.[1] It was made by Hitachi […]