[beforeafter] [/beforeafter] The perforated aluminum skin would replace the previously proposed glass facade. (Courtesy TJPA) It looks like Pelli Clarke Pelli's Transbay Transit Center, which stretches about three blocks through the city's Rincon Hill neighborhood, might go ahead with its first major piece of value engineering. According to the San Francisco Chronicle, the architects have suggested that the building's undulating glass skin become perforated aluminum. The move would meet federal safety guidelines and chop $17 million from the estimated $1.59 billion budget for the center's first phase. The Transbay Joint Powers Authority (TJPA) board will be asked to approve the change at its March 25 meeting. The structure is not expected to be complete before 2017. [beforeafter] [/beforeafter] "This is a dramatic change in material, but the philosophical change is not enormous," said Fred Clarke of the firm Pelli Clarke Pelli, who said the terminal would still feel light, not heavy. Chronicle critic John King warned that the move "could make the transit center less of a sinuous, snaking form—and more of a drab block—as it spans First and Fremont streets." On Pelli's side, Clarke argued that the wrapping would still be transparent. Of course he admitted: "Architects who do this kind of building must be very, very pragmatic."