SAN FRANCISCO (CBS SF) -- Crews working through the night at San Francisco's now-closed Salesforce Transit Center found no additional cracks after two were found in steel beams earlier this week, officials with the Transbay Joint Powers Authority said Thursday.
Overnight, crews assessed and tested the steel beams in preparation for shoring-up the area, which could happen as early as this weekend.
Also in preparation for the shoring, crews removed ceiling panels, moved light fixtures and utilities and are relocating some overhead systems for San Francisco Municipal Railway electric buses, according to TJPA officials.
The first crack was discovered in a steel beam on the third-level bus deck above Fremont Street on Tuesday by workers installing ceiling panels. The discovery caused TJPA officials to abruptly close the $2.2 billion facility and as well as the portion of Fremont Street located directly below the bus deck, between Howard and Mission streets.
As engineers were inspecting the first crack, about 2 feet 6 inches long, they found a second, smaller one on a parallel steel beam, which also runs across Fremont Street.
The beams support the third-level roof and bus deck as well as the fourth-story park above.
On Wednesday, TJPA Executive Director Mark Zabaneh said engineers were still attempting to figure out what may have caused the crack. They're looking into whether the cracks are related to the beams' fabrication, their installation or the center's design.
The beams were installed during construction in 2016 and have not been inspected since, which Zabaneh said, is standard protocol.
According to Dennis Turchon, the TJPA's senior construction manager, the steel beams used to construct the center were supplied by at least seven different manufacturers, all located in the U.S.
Stockton, California-based Herrick Corp. provided the steel in the cracking beams and about a third of all the steel used on the project. Construction of the transit terminal was part of the U.S. Department of Transportation's "Buy America" program.
Contractors and engineers have inspected other areas of the transit center where the beams are configured similarly and haven't found any other problems, Zabaneh said.
With the center's closure, all transit operators, including the San Francisco Municipal Railway and the Alameda-Contra Costa Transit District, will provide service from the formerly closed Temporary Transbay Terminal at Howard and Main streets. Both drivers and transit riders should expect delays in the city's downtown area.
The four-story Salesforce Transit Center opened in August, eight years after construction first began. Stretching four city blocks, the center boasts a 5.4-acre rooftop public park and space for pop-up retail shops, art displays and restaurants.
TJPA officials have said that the cracks are not related to the problems at the nearby sinking Millennium Tower, the 58-story luxury high-rise at 301 Mission St., which has sunk 16 inches.
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