The seismic performance of port structures has been well documented following recent earthquakes, and indicates that port structures are highly susceptible to earthquake-induced damages. These damages are primarily due to soil liquefaction and the associated ground failures. Sheet pile bulkheads provide vital intermodal and lifeline transportation links between water-side and land-side traffic, and are waterfront structures particularly vulnerable to liquefaction-induced damages. Due to the prevalence of liquefaction-induced damages, many ports are utilizing soil improvement techniques to mitigate these hazards. Many port authorities have proposed utilizing performance-based design criteria to limit potential earthquake-induced damages. The current design method for sheet pile walls (Mononobe-Okabe) is based on simple, limit equilibrium analysis techniques, which are poorly suited for performance-based design. Recent advancements in the seismic design of sheet pile walls have addressed some of the limitations of the current design methods, but are still inadequate for performing a complete, performance-based design for locations that contain potentially liquefiable soils and/or where soil improvement strategies have been instituted. This study has focused on conducting an empirical investigation and numerical modeling to determine the seismic performance of sheet pile walls, and the performancebased benefit of soil improvement through densification. A case history validated, nonlinear effective stress computer program was used to perform numerical parametric studies on various design parameters (earthquake properties, depth of sheet pile embedment, sheet pile wall stiffness, tie rod length, density of the backfill, and extent of soil densification). The results have been presented as a performance-based design method, and include a design chart that provides practitioners with a preliminary design tool that may be used to estimate the seismic deformations of sheet pile walls with or without soil improvement. The study has demonstrated that soil densification can greatly reduce the seismicallyinduced deformations, especially when the magnitude of soil improvement extends beyond the location of the anchor. The study has also demonstrated that the use of soil densification techniques for mitigating seismic hazards may not be adequate in limiting deformations to allowable limits, and that other methods of soil improvement (cementation, drainage, etc.) or structural improvements may also be required. / Graduation date: 1998

Graduation date: 2001