NATM SUBWAY STATION IN SOFT GROUND

Washington Metro is on the verge of completing the construction of the first NATM subway station and tunnels in soft ground in the United States of America. The station, Fort Totten Station, and tunnels located in Washington, D.C. on the Greenbelt Route were constructed using the New Austrian Tunnelling Method (NATM). The design of the station and tunnels was performed by the authors in compliance with the U.S. design codes. The construction contract for the station and tunnels was advertised giving contractors an option to bid on either conventional tunnels and cut-and-cover station or NATM tunnels and NATM station. The NATM construction alternative came in as a low bid at $48.7 million, saving approximately $1.8 million over the conventional option for the Washington Metropolitan Area Transit Authority. This paper follows the developments from the design through the construction of the NATM station. For the covering abstract see ITRD E108195.