Caltrans engineers and bridge architects received approval to construct a pair of models—one of calculations and digits, and one of concrete and steel—to determine the best way to protect the more than 400, 25-ft-tall anchor rods at the base of the San Francisco-Oakland Bay Bridge span’s signature tower.
The Toll Bridge Program Oversight Committee voted to approve initial recommendations from a panel of bridge experts that included Federal Highway Administration engineers, pre-eminent scholars and members of the U.S. Academy of Sciences and Engineering.
“You can’t overstate the value of us listening to the experts,” said Caltrans Director Malcolm Dougherty. “We took a step closer to resolving definitively and permanently the issues at the tower base.”
Last fall, Caltrans inspectors found that the contractor had not properly sealed the steel rods imbedded in the tower’s foundation, failing to protect them against the elements. The oversight committee solicited the help of these international experts in June of this year, and the panel began a thorough investigation into what actions, if any, should be taken to protect the rods that anchor the tower to its massive foundation.
Panel recommendations that were adopted included rendering a mathematical analysis of how the Bay Bridge tower would perform in a major seismic event, as well as full-scale construction model in which 17-ft-long steel rods would be cemented into sleeves mimicking their placement in the bridge.
The oversight panel declined to adopt a repair plan that could have cost more than $15 million, saying they wanted more information to make the most prudent resolution possible.