Liquefaction of loose saturated sands results in significant damage to buildings, transportation systems and lifelines in most large earthquake events. Liquefaction and the resulting loss of shear strength can lead to lateral spreading and seismic slope displacements, which often impact bridge abutments and wharfs, damaging these critical transportation links at a time when they are most needed for rescue efforts and post-earthquake recovery. While most updated seismic provisions now adopt a risk-targeted approach to design ground motions for superstructures, other critical aspects of geotechnical engineering, such as liquefaction and ground deformation evaluation, are still based on the older concept of deterministic hazard evaluation. Recent advances in performance-based earthquake engineering (PBEE) in geotechnical engineering (e.g., Kramer and Mayfield 2007; Rathje and Saygili 2008; Bradley et al. 2011; Franke and Kramer 2013) have introduced probabilistic uniform hazard-based procedures for evaluating seismic ground deformations within a performance-based framework from which the likelihood of exceeding various magnitudes of deformation within a given time frame can be computed. However, the ability to apply these performance-based procedures on everyday projects is generally beyond the capabilities of most practicing engineers. This study proposes to create and evaluate simplified performance-based design procedures for the a priori prediction of liquefaction triggering, lateral spread displacement, seismic slope displacement, and post-liquefaction free-field settlement using the standard penetration test (SPT).

1. Derive new simplified performance-based procedure for liquefaction triggering, lateral spread displacement, free-field post-liquefaction settlements, and Newmark seismic slope displacements. 2. Develop liquefaction parameter maps in GIS format associated with each of the hazards included in objective 1 at return periods of 475 years, 1033 years, and 2475 years for each of the states participating in the study. 3. Evaluate the new simplified performance-based liquefaction procedures against conventional (i.e., AASHTO) liquefaction analysis procedures. 4. Develop a simplified design procedure that will allow the designer to envelope the performance-based and conventional results to select which result will govern the design.

Tasks for this study include, regarding the participating states: 1. Derivation and validation of a new simplified liquefaction triggering model (Year 1). 2. Derivation and validation of simplified lateral spread displacement models (Year 1). 3. Derivation and validation of simplified post-liquefaction settlement models (Year 2). 4. Derivation and validation of simplified Newmark seismic slope displacement models (Year 2). 5. Assessment of grid spacing considerations in various seismic environments for map development (Years 1 & 2). 6. Development of liquefaction parameter maps at targeted return periods in GIS file format (Years 1 & 2). 7. Comparison of simplified, conventional, and deterministic analysis approaches (Years 1 & 2). 8. Development of a simplified design procedure and an analysis spreadsheet that incorporates both performance-based and conventional methods (Years 1 & 2). 9. Preparation of the annual and final reports (Years 1 & 2). 10. Dissemination of results in appropriate engineering journals and conferences (Years 1 & 2). 11. Technical Advisory Committee meetings (Years 1 & 2), including a final workshop to train partner states on the new performance-based liquefaction hazard methods.

The Principal Investigator for this study will be Dr. Kevin Franke of Brigham Young University. Dr. Franke has extensive experience with developing performance-based models to evaluate liquefaction and its effects. He has been the Principal Investigator/Co-Principal Investigator on previous performance-based liquefaction studies for the US Geological Survey and the NSF. His qualifications for this study are based on nearly 9 years of experience with performance-based and probabilistic design methods. Work is planned to begin in early 2014 and will run through 2016. At least one face-to-face meeting in Utah is anticipated with the project partners during the study, with travel costs covered by the project funds. The minimum partner commitment expected is $26,000, consisting of $13,000 for FY 2014 and $13,000 for FY 2015.