Development of a Simplified Performance-Based Procedure for the Assessment of Liquefaction-Induced Settlements Using Liquefaction Loading Maps

• Main Author: Error, Braden Michael
• Format: Others
• Published: BYU ScholarsArchive 2017
• Subjects: liquefaction; settlement; performance-based engineering; probabilistic; SPT; map-based procedures
• Online Access: https://scholarsarchive.byu.edu/etd/7210; https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=8210&context=etd

Liquefaction-induced settlement can cause extensive damage to infrastructure. Quantifying the amount of settlement that may occur after an earthquake is crucial to seismic design. The Pacific Earthquake Engineering Research (PEER) Center developed performance-based earthquake engineering (PBEE) as a probabilistic framework to characterize the risks associated with a seismic event. When applied to liquefaction-induced settlement, the PBEE framework provides a more complete and accurate representation of liquefaction hazard than other more conventional evaluation methods. Performance-based engineering is not widely used in practice, however, due to its complexity. In an attempt to make performance-based engineering methods more accessible to engineers for routine projects, this thesis derives a simplified map-based procedure to evaluating performance-based post-liquefaction settlements. A simplified PBEE procedure is developed for the Cetin et al. (2009) and Ishihara and Yoshimine (1992) empirical post-liquefaction volumetric strain models. The simplified map-based procedure involves obtaining a hazard-targeted value of vertical strain for a reference soil layer which is then adjusted using site-specific soil parameters to assess the liquefaction-induced settlement hazard at a particular location. This thesis derives the equations needed to perform a simplified analysis. The simplified procedure presented herein is then validated in which 15 cities across the United States are analyzed using both the simplified procedure and the full performance-based procedure. The simplified procedure is shown to adequately estimate a full performance-based procedure for post-liquefaction settlement. This thesis also presents SPLIQ, a spreadsheet tool that streamlines the derived simplified procedure in a single, user-friendly program.