Caltrans officials are seeking approval from the Toll Bridge Program Oversight Committee (TBPOC) to conclude its contract with the American Bridge/Fluor joint venture that built many parts of the bridge and hold the contractor accountable for project delays and faulty work.
TBPOC – which is the project’s governing body - must give its approval before Caltrans can conclude the contract and begin final negotiations over damages and penalties.
The problems were found in the self-anchored suspension bridge forming part of the San Francisco-Oakland Bay Bridge. Last year, Caltrans inspectors found that the contractor had not properly sealed more than 400 high-strength steel rods embedded in the tower’s foundation, failing to protect them against the elements. The threads of one rod stripped through its bolt and failed, prompting a thorough investigation of all the rods. Two of these rods were removed for testing, and the remaining rods underwent in-place earthquake-force tests. Testing concluded that the bolts could withstand a severe catastrophic earthquake.
Caltrans engineers will also seek TBPOC’s approval of recommendations put forward by an external panel of seismic experts to fix or mitigate the construction errors that potentially increased the risk of corrosion for these rods.
The expert panel analysed the anchor rods and their exposure to water, caused by poor grouting. The experts are submitting a list of potential tests they deem of varying importance for protecting the rods and foundation. The TBPOC may decide to order all, some, or none of the panel’s recommended tests.
Engineering analysis conducted last fall, indicates that the rods are not critical to the bridge’s performance and are a redundant system. Even if none of the rods were present, the bridge is expected to perform its lifeline function, weathering ground motions that only occur once every 1,500 years.