Developing Site-Specific Design Response Spectra for a Type F Site Due to Liquefaction

Abstract

This paper presents a practical approach to develop a site-specific design acceleration response spectral (ARS) curve for a soil profile Type F site due to liquefaction. A site development consisted of four main structures up to 12-stories high over a two- to three-level parking structure in Marina Del Ray, California. Based on the 2001 California Building Code (CBC) Table 16-J, the site was classified as Type F, requiring a site-specific evaluation. A site-specific probabilistic seismic hazard analysis (PSHA) was performed to develop the target uniform hazard spectra (UHS). An equivalent-linear one-dimensional seismic response analysis using the computer program SHAKE91 (Idriss and Sun, 1992) was performed and compared with the nonlinear effective-stress seismic response analyses using the computer code FLAC (Itasca, 2006) and D-MOD2000 (GeoMotions, LLC, 2007). Differences and deficiencies of the response spectra between using the equivalent-linear and nonlinear effective-stress seismic response analyses are discussed and the recommendations for structures having a different fundamental period of vibration are made.