Περίληψη:
Soil-pile interaction constitutes an important parameter in predicting the seismic response of pilesupported
structures. Towards a computationally attractive investigation of the interaction mechanism,
the p-y method, where the soil is represented as a series of independent springs distributed along the
pile shaft, has been extensively used. Along these lines several p-y curves for different soil-pile
systems have been proposed which are mainly based on in-situ pile tests under static or low frequency
cyclic loading conditions. However, soil-pile interaction under seismic excitation becomes more
complex due to the incident seismic waves scattered by the pile, thus modifying the p-y relationship
and introducing an additional damping mechanism at the soil-pile interface. In this paper, dynamic
soil-pile interaction is estimated based on back-calculated p-y curves, disregarding in a first stage any
potential soil-pile gapping mechanism. Pile displacements and soil reactions are derived through
double integrating and differentiating respectively the bending moments obtained along the pile shaft.
The p-y curves generated at each depth are utilized to derive frequency dependent springs and
dashpots, which may then be implemented within the framework of a Beam on Dynamic Winkler
foundation modeling of the soil-pile system. The proposed procedure is validated through centrifuge
tests results of a coupled soil-pile-structure system under real earthquake excitation and is also
compared to existing analytical formulas of frequency dependent springs and dashpots under steady
state harmonic excitation applied on the pile head. Analysis results reveal that for each one of the
loading scenarios considered, soil-pile interaction mechanism is adequately captured while utilizing
existing analytical expressions for the computation of dynamic soil spring supports may under certain
conditions lead to an overestimation of pile and structural response when the coupled soil-pilestructure
system is analyzed.