The firm performed a peer review (aka served as owner’s engineer) of this bridge and foundation design performed by others. This long-span bridge was unique in that it is located very close to the San Andreas Fault, is in a steep canyon subjected to landslides, etc. This review identified major deficiencies in the structural seismic design performed by others, including, among other things:
- Improper use of boundary conditions that resulted in significantly undersized members
- Failure to consider landslide loading on foundation elements, resulting in significantly undersized structural members
- Use of bracing systems not allowed by AISC 341, Seismic Design Manual
- Use of members that were not “seismically compact”
- Use of bracing members that did not meet seismic slenderness requirements
- The strength of bracing connections did not meet the requirements for ordinary concentrically braced frames to employ amplified seismic loads
- The results of our peer review required a complete redesign of the bridge and foundation.