Howard Street reopened around 8:30 p.m. after a lengthy closure that impacted traffic in the area.
Fire officials evacuated the building at 41 Tehama Street, South of Market Street. They say no residential buildings have been affected and are asking employees and tenants to go home and leave the area to stay safe. All non-essential construction personnel have been evacuated as well.
The slab is on the 30th floor of 41 Tehama, and fire officials were evacuating surrounding buildings at 41, 44, 56, and 58 Tehama Street. Buildings at 543, 531, 527, 505, 547, 555, 557 Howard Street were also being evacuated as well as a building at 235 Second Street.
A total of 16 buildings were evacuated.
The 500 block of Howard street has been shut down.
The project at 41 Tehama St. is a 37-story, 403-unit luxury residential tower near the Transbay Transit Center site. Construction began in 2015, according to a 2015 statement from development and construction management firm Lend Lease.
San Francisco police were working to close down streets surrounding the buildings. A specialist was being flown in to help deal with the situation, but fire officials anticipated the effort to take several hours.
"The building itself is not damaged or compromised in any way shape or form," said San Francisco Fire Chief Tom Siragusa. " It is the crane that is sitting on top of it and the forms that are holding it up that are of concern at this point."
If the slab falls, the fire department says it will likely damage surrounding buildings. A 911 call came in at 2:45 p.m. when crews were shoring up a crane near the center core of the building. One of the struts holding up a 30-ton crane failed and prompted the leaning of the crane and the pressure on the slab.
The building's developers, Hines and Investco Real Estate put out a statement just after 5 p.m. Wednesday saying in part: This afternoon, an incident occurred at the 33 Tehama site between levels 35 and 36 where an interior forming system had a partial hydraulic failure while being raised to the next level. The interior forming system and the concrete placement arm have been secured and are being evaluated by engineers to bring it back to level.
SFFD: Avoid Financial district. CHP closing down Fremont St. exit off Bay Br. pic.twitter.com/MxllJDV8MV— Cbarnard (@CornellBarnard) February 16, 2017