Seattle Tunnel Partners (STP), Washington State Department of Transportation’s (WSDOT) design-build contractor for the SR-99 (Alaskan Way Viaduct Replacement) Tunnel…

Near the banks of the Black River, a 7m (23ft) diameter Robbins Double Shield TBM and continuous conveyor system are…

The first elements of the 9.84m (32.3ft) diameter Caterpillar mixed face EPBM, which will be used to excavate the 2km…