SAN FRANCISCO (AP) – A second beam in San Francisco’s celebrated new $2 billion transit terminal shows signs of cracking, an official said Wednesday, a day after a crack in a nearby support beam shut down the building that opened just last month.

The first crack found by workers installing roof tiles Tuesday spans a beam holding up a park over the three-block-long Salesforce Transit Center and runs over a downtown street, said Mark Zabaneh, executive director of Transbay Joint Powers Authority, which operates the facility.

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He said the problems were localized to that area of the transit hub but it would remain closed “at least through the end of next week” as inspections continued. It’s not yet clear what caused the cracks at the facility that includes a bus deck, a towering sky-lit central entrance hall and a rooftop park with an outdoor amphitheater.

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“We’re working hard to rectify the situation,” Zabeneh said. “We’re very disappointed with what happened; we will get to the bottom of this.”

Mayor London Breed said the building would stay closed until it was safe to reopen. Its role in the broader transportation system is too important “not to act quickly to have definitive answers for the public, and someone needs to be held accountable once the cause is determined,” she said in a statement.

Engineers decided to shut down the station around 5 p.m. Tuesday, as rush hour started, once they learned the extent of the cracking.

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The transit hub, a commanding presence in the city’s South of Market neighborhood where construction is booming, sits adjacent to the so-called sinking condominium, Millennium Tower, which has settled about 18 inches (45 centimeters) since it opened over a former landfill in 2009.

Homeowners have filed multiple lawsuits against the developer and the city, some alleging that construction of the transit center caused the Millennium Tower to sink.

Zabaneh said he did not believe the cracked beams are connected to ongoing problems at Millennium Tower.

Engineer Joe Maffei also said the troubles at the terminal appear “completely unrelated” to the Millennium Tower’s sinking and tilting. He said there have been no public reports of similar settling problems with the terminal.

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The first crack was found near a weld on a stress-bearing horizontal beam and the second on a parallel beam, Zabaneh said. American steel was used in the center’s construction, he said.

Construction experts say it’s exceedingly rare for steel girders that support buildings to crack.

Engineer David Friedman said it’s likely the beams arrived without cracks, but that once the weight of the roof garden and other structures were added, “new stresses may have exacerbated the possible fabrication flaws.”

The beams likely passed inspection after installation, Maffei said.

“If that’s the case, it’s likely welding caused the problem,” he said.

Buses were rerouted to a temporary transit center about two blocks away that was used during the center’s construction. A downtown street that runs under the beam also was ordered closed indefinitely, causing traffic chaos at the same time some streets were closed for a conference sponsored by Salesforce that was expected to draw 170,000 attendees.

Numerous towering condo buildings have gone up in the booming South of Market neighborhood and several multistory construction projects are underway. Officials voted in 2012 to scrap building-height restrictions to encourage growth near the transit hub as San Francisco lures technology companies from Silicon Valley.

Julianna Cheng, 32, who lives in the neighborhood, burst out laughing when asked about cracking in the $2.2 billion transit center.

“I find it disappointing, but also kind of amusing because they built this really big, they spent a lot of money,” she said. “I feel like the money should have been used for a lot of other things.”

The online business software company Salesforce, which opened its adjacent 61-story Salesforce Tower earlier this year, bought naming rights to the transit center in 2017 as part of a 25-year, $110 million sponsorship agreement.


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Copyright 2018 The Associated Press.