Seismic Soil-Structure Interaction Analyses of an Underwater Bulkhead and Wharf System

This paper presents results of seismic soil-structure interaction (SSI) analyses of an underwater bulkhead and wharf system for the proposed Berth 145-146 Upgrade in the Port of Los Angeles (POLA), California, the first major undertaking of its kind at the POLA. The underwater bulkhead consists of strong center piles that are called king piles with sheet piles placed between them. The finite-difference computer program FLAC was used in the two-dimensional static and dynamic SSI analyses. To optimize the choice of king pile section and evaluate the effects of ground motions, the analyses focused on the behavior of the underwater bulkhead and wharf system for two king-pile configurations under three seismic motions. The seismic SSI analyses allowed selection of a smaller king-pile underwater bulkhead system compared with recommendations from simplified analyses, resulting in cost savings to the project.