It could cost as much as $1 million – twice the sum previously estimated – to learn what caused those two beams to crack at the Transbay Terminal and find other potentially vulnerable areas in the $2.5 billion project.
The Metropolitan Transportation Commission was brought in last year to help learn what led to the failures, and its work is now expected to continue at least through the end of April, Transbay officials say.
In September, workers found cracks in the two beams that cross Fremont Street and hold up the structure. NBC Bay Area’s Investigative unit was first to report that rectangular weld access holes that were cut into the 4-inch thick base of the beams were likely to blame for the cracks. The sharp corners of those holes, experts say, amplify forces and encourage cracks in steel.
The cracked beams and two other similar beams on First Street are being reinforced, which is expected to take until June.
Meanwhile, the projected cost of doing the review of the plans and construction of the project is expected to go from over $500,000 to as much as $1 million.
The governing board of the Transbay project is set to approve the money for the added study at its meeting Thursday.
Transbay officials say the added cost is for more extensive review of what triggered the cracks and more investigation into whether other areas of the structure may also be vulnerable to failure.
The cost of the study and the fix will likely ultimately be borne by the contractor deemed to be at fault for the problems, Transbay officials say.