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San Francisco construction site secured, but evacuation orders remain in place

Loose slab in SF
Loose concrete slab prompts evacuations in San Francisco 04:30

SAN FRANCISCO --  San Francisco fire officials Wednesday night said a crane and concrete slab on a South of Market high-rise construction project that were unstable and considered at risk of falling have been secured, but evacuation orders for nearby buildings remain in place, CBS San Francisco reports.  

Concerns about the stability of the crane and a 3,000-pound concrete slab at the top of the 35-story building under construction were raised Wednesday afternoon.

The project developer said in a statement that the 2:45 p.m. incident occurred when a system used to form concrete walls was being raised from levels 35 to 36 and had a partial hydraulic failure.

crane.jpg
An engineer with special expertise was being flown in to help the construction crews, crane operator and fire department figure out the best way to relieve the pressure on a concrete wall.  CBSN

San Francisco Assistant Fire Chief Tom Sirogusa said some of the closed streets in San Francisco’s South of Market will reopen Wednesday night after workers level the platform on the 35th floor of a luxury apartment building.

He says construction crews alerted authorities after the giant slab tilted Wednesday afternoon because a 30-ton concrete pump was sitting on top of it.

Sirogusa says officials decided to evacuate 16 office buildings and shut down several surrounding streets out of an abundance of caution.

Earlier, he said one a strut in a crane had malfunctioned.

He says the concrete pump sitting on top of the platform will be removed Thursday.

Fire officials described the incident as a failure of one of the struts supporting a crane at the building’s core, and said the tilt of the crane system caused one of the concrete walls and formwork to lean out.

During a fire department press briefing just before 6 p.m., San Francisco Fire Department spokesman Officer Jonathan Baxter said there is no danger of the concrete slab falling from the top of the high-rise project.

“At this point we have been able to vet – again, through our city inspectors as well as the contracting teams – that we have shored the formwork that is in question,” said Baxter. “The crane that is in question is also secure.”

Baxter insisted that media reports regarding the danger had been exaggerated.

“We’re seeing reports in the media that the crane is going to fall. That is false,” said Baxter.

The initial tweet indicated that the building at 41 Tehama was being evacuated due to the slab’s  “potential to fail” and that people should avoid the area. The correct address of the construction site was later determined to be 33 Tehama Street.


San Francisco Department of Emergency Management officials warned people to avoid an area between several streets.

Lendlease Senior Vice President Mary Costello said the 37-story, 403-unit luxury residential tower near the Transbay Transit Center is being developed by Hines and Invesco Real Estate. LendLease is the general contractor. 

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