Kleinfelder was the prime consultant responsible for providing the project management, bridge condition evaluation, retrofit studies, and replacement versus retrofit analysis for this project, including the completion of the environmental documents and designs to retrofit and rehabilitate the bridge.
Due to Highway Bridge Program funding sources and the historic classification, the project required extensive coordination with Caltrans District 11, Caltrans Division of Structures, Federal Highway Administration, and the State Historic Preservation. Seismic retrofit and replacement options were analyzed, and a comprehensive condition evaluation was performed on the bridge to identify rehabilitation needs and costs. The bridge is designated as a historic structure, requiring visual simulations of proposed alterations and an assessment of potential impacts on the bridge.
Ultimately, retrofit and rehabilitation was selected to preserve this historic resource. This approach required advanced engineering techniques, including a comprehensive non-linear time history analysis to model the structure’s response to earthquake motions. Due to the high-profile designation, all design criteria, approaches, and analyses were presented to an esteemed peer review committee for advice and concurrence.
Kleinfelder developed a specialized retrofit strategy for this bridge utilizing non-linear time history modeling. The concept was to isolate the superstructure from the existing columns and prestress the entire bridge for continuity. This allowed for minimal change to the visual character of the structure, while providing a seismically stable design.