Displacement-Based Procedures for Seismic Design of Pile-Supported Wharves at the Port Of Los Angeles and the Port Of Long Beach

Over the past several years, the Ports of Los Angeles (POLA) and Long Beach (POLB) have undertaken numerous engineering studies to improve the seismic design of pile-supported wharf structures. It was concluded that the displacement-based seismic design methodology results in more robust and economical wharf structures. The displacement-based design allows plastic hinges to form at predetermined locations, which can be readily identified and repaired after an earthquake. Both Ports sponsored and funded specialized studies and an experimental program at the University of California at San Diego (UCSD) to confirm seismic design assumptions. Also, port-wide ground motion studies were completed to develop acceleration and displacement response spectra and time-histories for the different levels of earthquakes specific to each Port. Displacement-based seismic design procedures for pile-supported container wharves are included in two separate documents: "The Port of Los Angeles Code for Seismic Design, Upgrade and Repair of Container Wharves" and the "POLB Wharf Design Criteria." This paper addresses the seismic, structural, geotechnical, and soil-structure interaction aspects of these documents and discusses various studies that were undertaken to support the development of the displacement-based seismic design.