Implications of the Observed Seismic Performance of a Pile-Supported Wharf for Numerical Modeling

The seismic response and performance of pile-supported wharves on sloping ground is not well documented due to an historical lack of instrumentation on port structures. Although general surface observations have been made at numerous ports following recent earthquakes, much more specific soil foundation-structure-interaction data could have been obtained with the more widespread employment of instrumentation. This paper presents the results of empirical and numerical analyses of recorded strong-motion data (SMD) from an array of instruments located on a pile-supported wharf and in the adjacent free field. Data were recorded with an instrumentation array at Berth 24/25 at the Port of Oakland, California, during the M7.0 Loma Prieta earthquake. The primary objectives of this project were to evaluate the SMD and identify the limitations inherent in capturing the complete dynamic character, including soil structure interaction, of a pier or wharf with a structural model. The project is expected to serve the professional engineering community by providing guidance in selecting appropriate techniques for seismic analysis and subsequent upgrade of existing port facilities.