Characterization of the seismic hazard and ground-failure hazard of a site using traditional empirical lateral spread displacement models requires consideration of uncertainties in seismic loading, site conditions, and model prediction. Researchers have developed performance-based design methods to simultaneously account for these sources of uncertainty through the incorporation of a probabilistic analytical framework. While these methods can effectively handle the various sources of uncertainty associated with empirical lateral spread displacement prediction, they can be difficult for engineers to perform in a practical manner without the use of specialized numerical tools. To make the benefits of a performance-based approach accessible to a broader audience of geotechnical engineers, a simplified performance-based procedure is introduced in this paper. This map-based procedure utilizes a reference soil profile to provide hazard-targeted reference displacements across a geographic area. Equations are provided for engineers to correct those reference displacements for site-specific soil conditions and surface geometry to produce site-specific, hazard-targeted estimates of lateral spread displacement. The simplified performance-based procedure is validated through a comparative study assessing probabilistic lateral spread displacements across several cities in the United States. Results show that the simplified procedure closely approximates the results from the full performance-based model for all sites. Comparison with deterministic analyses are presented, and the place for both in engineering practice are discussed.

Lateral spread is a seismic hazard associated with soil liquefaction in which permanent deformations are developed within the soil profile due to cyclic mobility. Lateral spread has historically been one of the largest causes of earthquake-related damage to infrastructure. One of the infrastructure components most at risk from lateral spread is that of deep foundations. Because performance-based engineering is increasingly becoming adopted in earthquake engineering practice, it would be beneficial for engineers and researchers to have a performance-based methodology for computing pile performance during a lateral spread event. This study utilizes the probabilistic performance-based framework developed by the Pacific Earthquake Engineering Research Center to develop a methodology for computing probabilistic estimates of kinematic pile response. The methodology combines procedures familiar to most practicing engineers such as probabilistic seismic hazard analysis, empirical compution of lateral spread displacement, and kinematic pile response using p-y soil spring models (i.e. LPILE). The performance-based kinematic pile response model is applied to a series of lateral spread case histories from the earthquake that struck the Limon province of Costa Rica on April 22, 1991. The M7.6 earthquake killed 53 people, injured another 193 people, and disrupted an estimated 30-percent of the highway pavement and railways in the region due to fissures, scarps, and soil settlements resulting from liquefaction. Significant lateral spread was observed at bridge sites throughout the eastern part of Costa Rica near Limon, and the observed structural damage ranged from moderate to severe. This study identified five such bridges where damage due to lateral spread was observed following the earthquake. A geotechnical investigation is performed at each of these five bridges in an attempt to back-analyze the soil conditions leading to the liquefaction and lateral spread observed during the 1991 earthquake, and each of the five resulting case histories is developed and summarized. The results of this study should make a valuable contribution to the field of earthquake hazard reduction because they will introduce a procedure which will allow engineers and owners to objectively evaluate the performance of their deep foundation systems exposed to kinematic lateral spread loads corresponding to a given level of risk.

For the most recent and correct article, please click here: http://ascelibrary.org/doi/abs/10.1061/9780784412787.086 This study examines the use of performance-based approaches in liquefaction hazard analysis. Two new methods of performance-based liquefaction initiation analysis are proposed which use the works of Juang et al. (2012) and Boulanger and Idriss (2012). Further advances are made by incorporating the performance-based magnitude scaling factors as proposed by Cetin et al. (2012). Using these new equations a comparative study is made between the three methods. Further comparisons are made between the performance-based approaches and the more widely used deterministic approaches. The comparisons reveal that on average for the 11 sites used in this study, the performance-based approaches tend to be slightly less conservative than deterministic approaches overall, with large differences possible for some locations in the country. They also reveal that the newer performance-based approaches are generally less conservative than the approach proposed by Kramer and Mayfield (2007). Some cases where this relationship does not hold true and the new relationships are more conservative are outlined.