Carquinez Bridge Seismic Retrofit
Seismic Evaluation
The eastbound Carquinez Bridge was built in 1958 as part of the route’s upgrade to interstate status. The total bridge width is 52 feet, including 12-foot lanes and two 2-foot shoulders. The cantilever steel truss spans a total of 3,300 feet in length at 140 feet above the channel. The western bridge constructed in 1927 as a private toll bridge provided three lanes of westbound (to San Francisco) traffic.
SC Solutions responsibilities for this project included:
- Creation of 3D finite element models of the 1927 (westbound) and the 1958 (eastbound) Carquinez Strait Toll Bridges,
- Non-linear time history analysis of the as-built and retrofitted strategy structures for static and seismic loads,
- Performed nonlinear time history analyses with multiple support excitations for several retrofit alternatives to determine the most cost effective, structurally sound retrofit configuration,
- Developed a thorough analysis methodology, which addressed critical issues in material and geometric nonlinear behavior for steel structures,
- Developed a rational set of criteria for evaluating levels of vulnerability and damage,
- Utilized detailed finite element models to estimate response of various bridge components,
- Performed nonlinear pile-soil interaction analyses to estimate the lateral displacement capacity.
This project demonstrated that through the use of nonlinear finite element analysis, problems related to large bridge structures subjected to strong ground motions could be mitigated efficiently and cost-effectively.