A SIMPLIFIED MODEL FOR NONLINEAR RESPONSE ANALYSIS OF SINGLE PILES UNDER DYNAMIC LATERAL LOADS

According to the fundamental conception of random vibration of hysteretic system, a new one-dimensional simplified model is proposed to study the lateral nonlinear dynamic response of single piles. The beam-on-dynamic-winkler-foundation hypothesis is assumed in this paper. A series of distributed nonlinear hysteretic, degrading springs described by the Bouc-Wen model are combined with distributed viscous frequency-dependent dashpots placed in parallel. The lateral nonlinear action of the soil to the single pile can be simulated by the nonlinear springs and the energy dissipation in the motion is accounted for with the dashpots. It can capture the main characteristics of the nonlinear behavior of the single pile and reveal the important role of several nonlinear factors affecting the response of single pile with this model, such as effect of hysteresis, degradation and yielding of the soil surrounding the pile, and separation between soil and pile. The parameters of the proposed model are readily associated with the physical parameters governing the response of actual pile-soil system, and widely accepted code recommendations or empirical formulas are used for their estimation. The predictions of the model are in very good agreement with measured values from experiments.