WMATA Section F6b, Branch Route

Owner:	Washington Metropolitan Area Transit Authority
Client:	Parson Brinkerhoff / PHG Wong and Associates
Service:	NATM Design
Estimated cost:		Commencement:	January 10, 1996	Completion date:	December 30, 1997
Location:	Washington, DC United States
Technical data:	Subway running tunnels 2 x 1,400 ft (427m) long, 20' wide x 21' high with a section of 342 sqft (32m²). Tunnels included a section with chemical grouted arch pre-support in P2 sands installed using directional drilling methods. "Closed Bag" PVC waterproofing using sectioning system. Unreinforced concrete final lining.
Geology description:	Tunneling through compact to very compact fine to medium sand of the P2 stratum (below the ground-water table) and stiff to hard plastic to silty clay of the P1 stratum.
Geology types:	Soft ground
Categories:	Urban Rail/Bus Stations and Tunnels
Bid cost:		Final cost:	$21,000,000
Service areas:	Tunnel Design & Specialities