This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).
An area of engineering practice that is not well defined is the seismic response of sites requiring site-specific evaluation because of problematic soil conditions. This follows from the limited fundamental understanding of the behavior of soft soils. Deep deposits of soft soils exist in many urban areas within the United States (e.g., Boston, Charleston, Memphis, New York, and San Francisco). U.S. building codes require site-specific evaluations at these sites, but established guidelines for performing these evaluations are not yet available. This project will develop the data and analyses needed for such guidelines.
The project intends to investigate the seismic response of deep soft soil sites by performing advanced cyclic simple shear and triaxial testing of soft soils to characterize their dynamic properties and by developing advanced numerical site response procedures that can be used for performing site-specific evaluations of these deposits. The project?s data and findings will lead to an improved fundamental understanding of the cyclic response of soft soils and yield practical guidelines for addressing the special concerns involved with analyzing the seismic response of these deposits. Outcomes will include correlations of dynamic soil properties with available in situ test results and simplified period-dependent site amplification factors for developing preliminary design spectra for these sites. Critical lessons will be learned from this study, because the soils and levels of earthquake shaking investigated in this project cover a wide range of soft soil sites.
