SAN FRANCISCO (CBS SF) — Crews working at the closed Salesforce Transit Center in downtown San Francisco will temporarily close a portion of First Street Friday night in order to add support to the center above the street as a precautionary measure.

First Street Closure

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First Street between Howard and Mission streets will close at 9 p.m. over the next few days as crews work to reinforce the bus deck above. The stretch of street will reopen at 5 a.m. on each of the following days.

No cracks were found in steel beams above First Street but two cracks were found in steel beams on the bus deck above Fremont Street on Sept. 25, prompting the immediate closure of the transit center and Fremont Street.

Mark Zabaneh, executive director of the Transbay Joint Powers Authority said in a statement, “Because Fremont and First streets are similarly designed, to be prudent, we have decided to reinforce First Street as a proactive measure.

“We have inspected and are continuously monitoring First Street and have found no issues, but because of its similar design to Fremont Street, we think the most prudent course of action is to reinforce First Street as we repair and reinforce Fremont Street. This will help us reassure the public and make the building as safe, stable and secure as possible,” he said.

Crews have already begun shoring up the transit center above Fremont Street in order to help take the load off of the cracked beams.

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Fremont Street is set to reopen to traffic by Oct. 12, in time for the morning commute, TJPA officials confirmed Friday.

Once the shoring system is completely installed, engineers with contractor Webcor/Obayashi and structural engineering firm Thornton Tomasetti will take samples of the steel to determine what caused the cracks. The sampling and testing could take two weeks, with engineers determining a cause possibly by early November.

Once a cause is found, then engineers can begin working on permanent repairs.

Earlier this week, Zabaneh said that once engineers begin repairs, reopening the transit center’s fourth-story park while the rest of the center remains closed to the public is a possibility.

The $2.2 billion transit center opened in August and served as a regional bus depot, with future plans to connect it to Caltrain and the state’s high-speed rail line.

Buses are now operating from the Temporary Transbay Terminal at Howard and Main streets in San Francisco, where they operated from before the transit center opened.

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