Influence of damping models on dynamic response of pile group

Abstract

The analysis of pile groups in earthquake prone areas and subjected to seismic loading involves computing the ultimate load to arrive at the safe load and determining the maximum deflection to ensure that a serviceability criterion is reached. In the present study, a 2x2 pile group embedded in liquefiable Nevada sand layer and underlain by a non-liquefiable cemented sand layer and subjected to 2001 Bhuj earthquake motion is analyzed using finite difference based geotechnical program FLAC3D. The damping models considered in the present study includes Rayleigh damping, local damping, artificial viscosity and Hysteretic damping (Default, Hardin, sig3 and Sig4). Maximum pile group displacement of 9.1cm is observed when sig3 Hysteresis damping model is used while Hardin model generated dynamic bending moment of 17.5kNm and 15kNm on front and rear piles, respectively. Thus damping models have a significant influence on dynamic response of pile group founded in liquefiable soil and should be included for dynamic analysis of various geotechnical structures.