Development of liquefaction-targeted design basis in U.S. seismic provisions

Earthquake Spectra
By: , and 

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Abstract

Seismic design criteria for new buildings in the United States have historically focused on life safety performance objectives through minimizing the potential for structural collapse. Development of design criteria to meet this performance objective has evolved over time, leading to the current, risk-targeted maximum considered earthquake (MCER) design basis. Corresponding MCER seismic design loads incorporate the full range of probabilistic ground motion hazard information available from U.S. Geological Survey National Seismic Hazard Models, as well as a representation of the uncertainty in structural collapse capacity. Despite these considerable advances in structural design criteria, guidelines for geotechnical hazards such as liquefaction-induced damage, which continue to be based on uniform ground-shaking hazard (i.e., MCE ground motions), are not well-connected with risk-based, collapse prevention performance objectives. This study, undertaken as part of Building Seismic Safety Council efforts to update recommended seismic provisions through the National Earthquake Hazards Reduction Program, presents probabilistic, liquefaction-targeted design objectives and corresponding ground motion parameters, with a focus on improving consistency in first-level screening criteria for liquefaction hazard assessment. This study identifies a potential maximum acceptable annualized probability of liquefaction triggering (PL,max) of 2.5% in 50 years, above which liquefaction consequences and potential mitigation measures would be considered. The PL,max-based design basis is calibrated to effective probabilistic liquefaction hazard levels obtained in practice using current MCE peak ground accelerations, and could be implemented via a new liquefaction-targeted maximum considered earthquake (MCEL) peak ground acceleration (PGAL). The proposed PGAL is derived from probabilistic liquefaction hazard curves and includes uncertainties inherent to liquefaction hazard modeling. The potential design effects of the proposed PGAL are demonstrated via comparison with current MCE PGA levels, effects on first-level liquefaction screening analyses, and improvements in the consistency of PL,max levels across the United States, and for a wide range of site conditions.

Suggested Citation

Makdisi, A.J., Kramer, S.L., Bassal, P., Maurer, B.W., Perkins, B., Anderson, D.G., Crouse, C.B., Dashti, S., and Teague, D., 2026, Development of liquefaction-targeted design basis in U.S. seismic provisions: Earthquake Spectra, v. 42, no. 3, e70097, 24 p., https://doi.org/10.1002/esp4.70097.

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Publication type Article
Publication Subtype Journal Article
Title Development of liquefaction-targeted design basis in U.S. seismic provisions
Series title Earthquake Spectra
DOI 10.1002/esp4.70097
Volume 42
Issue 3
Publication Date July 09, 2026
Year Published 2026
Language English
Publisher Wiley
Contributing office(s) Geologic Hazards Science Center - Seismology / Geomagnetism
Description e70097, 24 p.
Country United States
Other Geospatial conterminous United States
Additional publication details