Procedure for the Empirical Evaluation of Lateral Spread Displacement Hazard Curves

Liquefaction-induced lateral spread has caused substantial damage to buildings, bridges, embankments, buried utilities, and other critical components of infrastructure in numerous past earthquakes. Although many practitioners use analytical Newmark-based seismic slope displacement models to estimate liquefaction-induced lateral spread displacements, empirical regression models remain popular among most practicing professionals today. However, all lateral spread estimates have a significant level of uncertainty. This paper introduces a procedure to develop performance-based estimates of liquefaction-induced lateral spread displacement by incorporating a widely used empirical model into a probabilistic framework. Utilizing the same principles used in probabilistic seismic hazard analysis, the empirical lateral spread equation is modified and inserted into a performance-based framework modeled after the framework introduced by the Pacific Earthquake Engineering Research Center. Lateral spread hazard curves are developed for 10 sites located across the United States using a generic soil profile. The results of the performance-based lateral spread method are compared with those of conventional pseudoprobabilistic methods. Consistent application of the conventional methods is shown to produce inconsistent actual lateral spread displacement hazards in different seismic environments. Practical design implications for the proposed performance-based procedure are discussed, and a simple example application is presented.