Dynamic Lateral Response of Piles in Coupled Mode of Vibration

Abstract

An approximate numerical method of analysis is presented to study the dynamic response characteristics of piles embedded in a homogeneous elastic soil half-space subjected to coupled horizontal and rotational mode of vibration. The excitation consists of a harmonic horizontal force and moment applied at the pile head or at the centre of gravity of pile supported footing. The theory accounts for soil-pile interaction in a relatively simple manner. The differential equation of damped horizontal vibration of pile so developed has been solved using the finite difference technique and by satisfying the appropriate boundary conditions. The nodal displacements of pile thus obtained are utilised to calculate the dimensionless stiffness and damping parameters of pile and the footing in predicting the dynamic lateral response of piles. The dimensionless stiffness and damping parameters are found to be frequency-dependent and vary with slenderness ratio and other factors. Theoretical results are compared satisfactorily with the reported experimental response of footings supported by single piles and also with other theories, establishing thereby the validity of the proposed method.