TYLin provided design and construction support for the dismantling of the main span of the old San Francisco-Oakland Bay Bridge in Oakland, California.
TYLin worked closely with the California Department of Transportation (Caltrans) to design the safe removal of this massive structure. The 2,416-foot-long cantilever truss superstructure had a 1,400-foot-long main span, including cantilever and suspended spans, and consisted of 35 million pounds of steel and 30 million pounds of concrete deck.
The disconnection of the suspended span was a significant challenge. The locked-in forces in the system required an in-depth understanding of the bridge’s original construction sequence from the 1930s, as well as the subsequent retrofits of the 1960s and 1990s. Ensuring the stability of the remaining truss during dismantling was vital to the operation.
TYLin worked with Caltrans Construction to provide active construction support throughout the process, including expedited review of contractor submittals. The team developed conceptual solutions to critical issues in the contractor’s proposed dismantling sequence that might affect the local or global stability of the truss. Stability analyses were performed to maintain the stability of the structure during all stages of the dismantling operation.
- TYLin provided 3D construction staging models for the sequence leading to the critical disconnection of the suspended span.
- The TYLin team worked with Caltrans to mitigate environmental issues that might impact the schedule.
- Environmental challenges overcome included the seasonal restrictions of pile driving in bay mud, nesting of cormorant birds in construction zones, and lead abatement of old steel.