ABSTRACT
ABSTRACT: Current state-of-practice methodologies for evaluating seismic liquefaction potential and their applications to bridge design are presented. Issues involved in the assessment of liquefaction hazard at a bridge site are discussed, including soil susceptibility, seismological parameters, and site response. The evaluation of soil resistance using empirical procedures based on geotechnical field testing, including Standard Penetration Test (SPT), Cone Penetration Test (CPT), and Seismic Crosshole/Downhole tests (SC/SD) are presented. Examples are given for two bridge projects in the New York City (NYC) Metropolitan area, analyzed using the 1998 NYC Department of Transportation (DOT) Seismic Criteria Guidelines. Available methodologies based on field tests were applied and comparisons between them were made. Design recommendations are outlined for the two bridges, including site-specific response spectra and equivalent safety factors against liquefaction. The paper gives recommendations for defining and selecting appropriate design parameters for areas of moderate seismicity, such as NYC.
