Hysteretic Dissipation of Piles under Cyclic Axial Load

Abstract

A simple finite element model for predicting the hysteretic behavior of a single compressible pile embedded in a possibly inhomogeneous soil under cyclic quasistatic axial load is presented, along with applications to two actual field tests of piles driven in dense sand. Predicted settlement, resultant shaft and tip loads after repeated loading and unloading in the two cases are within 5% of the field test measurements. The model permits calculating the amount of energy dissipated in the soil during a loading cycle, which can be used in establishing equivalent viscous damping coefficients for studying the dynamic response of driven piles. Degradation of the stiffness and strength of the soil are taken into consideration by means of a simple rule. Due to its simplicity, the model is well suited for carrying out parametric studies to examine the sensitivity of the response to the various system parameters.