Demolition of an existing 35,000-square-foot, asbestos-contaminated warehouse was needed in Amtrak’s King Street Coach Yard in Seattle to make room for a new 31,000-square-foot locomotive service facility. This new maintenance shop sits atop 178 driven steel pipe piles, each with a diameter of 24 inches. These piles were driven to a depth averaging 180 feet below grade. A heavily reinforced structural system of concrete-grade beams ties the pile foundations together to support the new preengineered metal building (PEMB).
The 380 feet long x 80 feet wide PEMB houses a 55-ton overhead bridge crane and a 125-ton drop table that is used to switch out traction motors and locomotive axles (trucks) for Amtrak’s maintenance needs. The drop table is located in a 25-foot-deep concrete pit at the center of the locomotive shop, as the trucks need to be removed from the underside of the locomotives.
The complexity of this structural system of building components and equipment is amplified when the poor soil conditions, high water table, high seismic hazard zone, and dynamic loading from locomotives are all considered.
Other infrastructure upgrades in Amtrak’s yard included an underground storm-water detention system, 12,000 lineal feet of yard track demo, realignment, and installation of new yard track. An underground force main, for industrial waste, was added and routed more than 1,000 feet from the new locomotive shop to Amtrak’s existing on-site industrial waste treatment facility. This line paralleled a new sanitary sewer force main that linked two existing buildings on the Amtrak site with the new locomotive shop’s needs. Together, four underground lift stations with depths of up to 15 feet were needed to route more than 2,500 lineal feet of industrial waste and sanitary lines through a variety of unforeseen underground rail-yard debris and obstacles.