Underground

Location

San Juan, Puerto Rico

Owner

Puerto Rico Highways & Transportation Authority

Contractor

Kiewit-led Joint Venture

Completion

May 2003

As America's first design-build underground transit project, the $250+ million underground section of the Tren Urbano-Rio Piedras rapid transit system involved constructing a one-mi.-long tunnel and two stations for the Puerto Rico Highways and Transportation Authority.

Led by Kiewit Construction Company, a subsidiary of Kiewit Corporation, this joint venture project used three different soft-ground tunneling methods to address ground conditions. Finished in May 2003, the work involved the delivery of retained-cut/retained-fill at both ends of the project, as well as cut-and-cover double and single-cell box structures. A total of 1,300 ft. of the tunnel has cast-in-place lining. The project has 1,400-ft. twin transit tunnels excavated with an Earth Pressure Balance Machine, 1,260 ft. excavated using the New Austrian Tunneling Method, one cut-and-cover station and a 75-ft.-wide by 55-ft.-high by 410-ft.-long underground mined station constructed using stacked drift techniques.

The work was performed within the busy urban area of San Juan with only minimal disruption to normal surface activities. All facilities were constructed with full waterproofing and drainage systems. Mass Electric Construction, a subsidiary of Kiewit Corporation, installed the control center, including traction power, train control, and power communications systems for the 10.4-mi. extension.

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