One of few certainties with Transbay center: Repair costs covered by warranty

Workers at the Transbay Transit Center unload hydraulic jacks that will be used to temporarily shore up the damaged building while two cracked beams are inspected. Workers at the Transbay Transit Center unload hydraulic jacks that will be used to temporarily shore up the damaged building while two cracked beams are inspected. Photo: Michael Cabanatuan Photo: Michael Cabanatuan Image 1 of / 34 Caption Close One of few certainties with Transbay center: Repair costs covered by warranty 1 / 34 Back to Gallery

The cost of repairing the Transbay Transit Center, a task that is likely to take weeks and cost millions, will be covered by warranty, officials confirmed Wednesday.

The general contractor or its subcontractors are responsible for repairing any construction flaws, not the center’s operator, the Transbay Joint Powers Authority.

That is one of the few certainties or easy answers about the broken transit hub, which has been shut down since the discovery of cracks in two critical support girders on Sept. 25, six weeks after it opened.

The damaged section of the $2.2 billion transit center, over Fremont Street, has been stabilized, and construction crews plan to erect temporary support towers on three levels of the structure this week. But until that work is done, engineers can’t complete tests to determine the cause of the cracking and devise a fix.

Repairs likely will be costly. Asked for a rough estimate after a meeting of the authority Tuesday, Executive Director Mark Zabaneh shrugged and said: “Thousands? Millions?”

Whatever the cost, he said Wednesday, “The transit center is under warranty for two years and once we determine the cause of this, we will make sure the proper entity is held responsible.”

The Transbay JPA’s agreement with general contractor Webcor/Obayashi requires it to correct substandard work “at no cost to the TJPA for a period of two years after substantial completion.”

The contract states that the contractor “shall warrant and guarantee the work against defects in materials and workmanship for 24 months” and that work will be “free of any defect of equipment, material and installation.”

The warranty calls for the contractor to promptly “remove, replace or correct work ... which is damaged or found defective” upon written notice, and allows the TJPA to do the work itself, at the contractor’s expense, if it’s not fixed “within a reasonable time.”

It also says: “The contractor shall warrant and guarantee the work against defects in materials and workmanship for 24 months.”

The Transbay Transit Center opened Aug. 12 after nearly eight years of demolition and construction. A certificate of occupancy has been issued but work is not complete. Workers are still installing public art, lighting and sidewalks in Shaw Alley near the complex as well as trim around some of the center’s ceiling tiles.

It was during that ceiling work that the fissures in the first steel girder were discovered. Transbay officials quickly shut down the center — “out of an excess of caution,” they said — as well as Fremont Street where it passes under the building.

Transbay officials say they could reopen Fremont Street, a major route into downtown San Francisco from the Bay Bridge, this week — but certainly by Oct. 12 — when the temporary support towers are installed.

After that occurs, forensic engineers can take samples from the damaged steel beams and scrutinize them to determine the cause of the cracking — a process that should take about two weeks.

Designing a fix for the problem, and getting it reviewed by an independent committee of outside engineers, design and metallurgy experts will take weeks more. Then, finally, construction workers can repair the problem, which will likely involve adding material to strengthen the damaged beams, said Dennis Turchon, senior construction manager.

Zabaneh said it’s too early to put a target date on reopening the center to buses and commuters because the extent of repairs is still uncertain. But the popular 5.4-acre rooftop park could reopen in early November.

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