A crane on a trestle lifts an architectural steel assembly, including a 9-ft-tall cast node, into place along the perimeter of the $4.5-billion Transbay Transit Center, which is taking shape in seismically active San Francisco. The node picks, followed by more steel tubes that link to form a four-and-a-half-block-long exoskeleton, is repeated more than 300 times. The lateral-load-resisting system will allow immediate reoccupancy of the 1,425-ft x 171-ft "groundscraper" after the "Big One."
The architect for the five-level bus-and-rail hub calls the 304 expressed custom nodes, which weigh from 2 tons to 23 tons each, robust and muscular. "We are trying not to let them look light or delicate because they are anything but [that]," says designer Fred Clarke, senior principal with Pelli Clarke Pelli Architects (PCPA).