Stochastic characterization of the dynamic response of a pile

Abstract

The design of pile foundations subjected to large harmonic loads produced by machine vibrations is usually controlled by their service limit state. Verification of this condition under current design philosophy requires the estimation of the probability of failure. However, the deterministic nature of current design procedures does not facilitate such calculations. This paper presents a stochastic model for the dynamic pile response under harmonic loading considering the uncertainty in the mechanical parameters of the soil and the pile itself. The purpose of the model is to quantify the uncertainty in the pile response in terms of its impedance. A sensitivity analysis of the design parameters and stochastic variables is performed to quantify their impact on the uncertainty of the pile response. The effect of pile diameter and uncertainty of its properties, mean soil stiffness, and the selection of distribution models for the random variables are evaluated. Useful insights are gained into the stochastic behavior of the model and the characterization of the pile stiffness and damping components of the pile. This approach may provide a valuable first step towards the development of a comprehensive reliability analysis of this foundation type.