SF traffic woes to continue in week two of Transbay closure

Commuters make their way into the Temporary Transbay Terminal after the Salesforce Transit Center was closed Tuesday, Sept. 25, 2018, in San Francisco. San Francisco officials shut down the city's celebrated new $2.2 billion transit terminal Tuesday after discovering a crack in a support beam under the center's public roof garden. Coined the "Grand Central of the West," the Salesforce Transit Center opened in August near the heart of downtown after nearly a decade of construction. It was expected to accommodate 100,000 passengers each weekday, and up to 45 million people a year. (AP Photo/Eric Risberg) less Commuters make their way into the Temporary Transbay Terminal after the Salesforce Transit Center was closed Tuesday, Sept. 25, 2018, in San Francisco. San Francisco officials shut down the city's celebrated ... more Photo: Eric Risberg / Associated Press Photo: Eric Risberg / Associated Press Image 1 of / 34 Caption Close SF traffic woes to continue in week two of Transbay closure 1 / 34 Back to Gallery

Dreamforce has vanished along with its nearly 200,000 conference attendees and workers, and Howard Street has reopened, but the continued closure of the new Transbay Transit Center and a block of Fremont Street mean traffic troubles are certain to continue Monday and probably through the week.

Construction crews used giant hydraulic jacks and steel I-beams Sunday to brace the area above Fremont Street where cracks were discovered last week in two massive support girders.

The bracing operation has just begun, and Fremont Street remains closed between Howard and Mission streets. Traffic flowing into downtown from Interstate 80 is being steered east and west on Howard Street. Delays are expected and drivers have been advised to avoid the area.

The end of the Dreamforce conference, however, means Howard Street will reopen between Third and Fourth streets, which should ease South of Market traffic, especially on Third.

How long Fremont Street remains closed is uncertain. The bolstering of the transit center’s cracked steal beams just started Sunday, and a comprehensive analysis of the damage and how to fix the the cracks can’t proceed until weight is removed from the beams.

Mark, Zabaneth, executive director of the Transbay Joint Powers Authority, which built and operates the transit center, said officials may know Monday or Tuesday how long Fremont Street will need to stay closed.

When it reopens, he said, drivers will need to steer around the bracing that’s been installed in middle of Fremont Street. The center’s bus ramp and deck will remain closed.

Buses, including Muni and AC Transit Transbay lines that used the transit center, have been rerouted to the Temporary Transit Terminal at Howard and Beale streets.

Michael Cabanatuan is a San Francisco Chronicle staff writer. Email: mcabanatuan@sfchronicle.com Twitter: @ctuan