Proceedings of the 21st Annual Members' Conference, 1996, San Francisco, CA, (DFI)
Modeling & Analysis of the San Francisco/Oakland Bay Bridge Timber Piled & Retrofitted Foundations
James A. Mason, MS, PE
In itís original as-build state, the San Francisco Oakland Bay Bridge (SFOBB) would probably be severely damaged in the event of a maximum credible earthquake on either the San Andreas or the Hayward fault. Analysis by the California Department of Transportation, Engineering Service Center, Office of Earthquake Engineering, Office of Structure Foundations, and the Office of Structure Design indicates the entire as-built structure is vulnerable at its strength limit state. From the steel latticed superstructure down to the original timber piles, all elements would be susceptible to seismic overloading. The seismic retrofit of the SFOBB has demanded technical innovation for all components throughout the entire structure. This paper is the product of the structural design check for the seismic retrofit of Piers E-6 to E-16. The foundation modeling is based upon preliminary soils information. Seismic performance criteria, seismic loading conditions, comparison of equivalent static and time-history analysis methods, and retrofit solutions for the original timber piled foundations, piers E-6 to E-16, will be presented. Discussion of the imposed limit states will also be provided. As an example, analysis, dynamic modeling, and design solutions for the seismic retrofit of Pier E-6 will be provided.
|article #89; publication #18 (AM-1996)|