Performance-based design and evaluation for liquefaction-related seismic hazards

Soil liquefaction can cause serious damage both during and following strong ground shaking. The liquefaction-induced hazards discussed in this research include ground motion modification, flow slides, lateral spreading, and ground surface settlement. With the exception of ground motion modification, all of these post-liquefaction hazards are commonly estimated using empirical methods. Uncertainty in these empirical relationships is usually not explicitly accounted for, which affects the accuracy and consistency of liquefaction-induced hazard prediction. Some investigators have proposed probabilistic models to deal with post-liquefaction problems, such as residual strength and lateral spreading displacement. A probabilistic model for post-liquefaction settlement, however, is not currently available.;The goal of this dissertation is to provide improved procedures for estimation of post-liquefaction hazards, and to suggest procedures for computing the probability of exceeding a damage level of concern. This has been accomplished by implementing the performance-based earthquake engineering (PBEE) framework developed by the Pacific Earthquake Engineering Research Center (PEER) into a limit state exceedance formulation, which involves concepts of demand (loading) and capacity (resistance). In the proposed procedures, the demand of a post-liquefaction hazard is estimated using PEER PBEE framework, and the capacity is characterized probabilistically for various damage levels. For design purposes, a limit state exceedance for a specific damage level is a special case in the PBEE computations. The mean annual rate of exceeding this specific damage level for a liquefaction-related hazard of interest then can be computed and applied to engineering design.;An important accomplishment of this research was the development of procedures for performance-based analysis of post-liquefaction settlement. The development required characterization of a maximum volumetric strain. A complete procedure for estimating post-liquefaction settlement was developed based on the PEER PBEE framework with consideration of maximum volumetric strain.;An analysis tool for this research was developed as a final product. WSLiq, the analysis tool, provides a user-friendly interface and various features to help engineers understand and evaluate liquefaction-related hazards using conventional, advanced, and performance-based procedures. WSLiq provides a tool that can be used assist engineers with liquefaction hazard evaluation and design.