Influence of Dynamic Behavior of Soft Clay on Seismic Pier Response at the Port of San Francisco

This paper focuses on the seismic performance of a pile-supported pier structure considering the potential for large-scale, earthquake-induced, slope deformations controlled by a layer of soft clay. The assessment incorporates the strain-dependent shearing resistance of the soft clay from moderate strains associated with peak dynamic strength, to intermediate strains at residual strength, and ultimately large strains at fully-remolded strength. Primary challenges for the project included drilling through an existing rock fill to obtain high-quality samples of the underlying soft clay for laboratory characterization of the static, cyclic, and post-cyclic stress-strain behavior of the clay. This paper underscores the importance of the laboratory testing for evaluation of the structural performance of a pile-supported pier structure impacted by permanent foundation movements during earthquakes. Structural aspects of the assessment are presented by Soderberg and Liu as part of the Proceedings of the Ports ’19 Conference.