Unveiled on April 22, the final design for the $1.5-billion Transbay Transit Center in San Francisco will feature high-level seismic and environmental elements. The five-story glass-and-steel station, billed as the Grand Central Station of the West, will consolidate 12 transit operations, including anticipated high-speed rail.

The Bay Area Transbay Transit Center will feature green-friendly and seismic-resistant elements.
Photo: Pelli Clarke Pelli Architects
The proposed transit hub would be a 1,400-ft-long structural tube with moment frames.

The Transbay Joint Powers Authority hub, designed by New Haven, Conn.-based Pelli Clarke Pelli Architects, includes a place-marker for an iconic 1,200-ft-tall tower. Part of a $4-billion mixed-used project, the tower is still the subject of financial and zoning negotiations. The hub, which will host Bay Area Rapid Transit, Caltrain, Greyhound bus services, Amtrak and high-speed rail, will replace a smaller, concrete-framed terminal built in 1939.

Thanks to a $400-million American Recovery and Reinvestment Act grant, the first phase will include construction of an underground box for the train station hub.

The building’s roof will include a 5.4-acre public park and amphitheater, which will add some 35,000 tons, requiring a robust design, says Bruce Gibbons, senior principal in the Los Angeles office of Thornton Tomasetti, the project’s structural engineer.

The building is designed to meet Leadership in Energy and Environmenal Design Gold-certified standards, with a geothermal and graywater recycling system. Plans also include features to withstand a major earthquake.

The building is essentially a 1,400-ft tube with moment frames every 42½ ft to create redundancy; the tube is broken into three structures, with 24-in. modular expansion joints supported by a 5-ft-thick concrete mat. Glass panels will be held in place by open joints at the corners, separated by 4 in. of air to prevent contact during a quake, Gibbons says.

A joint venture of San Mateo-based Webcor Builders and Japanese firm Oba-yashi Corp. won the construction contract in 2009 and will begin demolishing the existing terminal in August. Construction could be complete by 2017.

A temporary terminal under construction since December 2008 will serve current operators during the demolition phase.