Numerical simulation of the dynamic response of batter piles and pile groups

Batter piles are most commonly used to resist large lateral loads caused by winds, tidal waves and soil pressure as experienced by offshore structures, bridges, and towers in general. The details in literature on the dynamic behaviour of these batter piles based on in-situ tests are limited. The present study focused on dynamic lateral behaviour of single batter piles and batter pile groups subjected to machine induced vibrations using 3D finite element (FE) analysis. The coupled soil-pile system consisting of soil mass, pile/pile groups, and oscillator motor assembly mounted on the top of the pile cap has been modelled using ABAQUS. The soil mass was considered as a half space through appropriate model dimensions and absorbing boundary conditions (using infinite element). A hybrid modelling approach was adopted to obtain the bending moment along the length of the pile. The 3D FE models were developed based on the field tests conducted by the authors on bored cast in-situ batter piles (three batter angles 0°, 10° and 20°) and pile groups (0° and 20°). Dynamic lateral loads were applied on the pile cap in the form of sweep loads for varying force levels of excitation separately. The responses of the 3D FE models were obtained in terms of displacement time histories at mid height of pile cap, displacement, and bending moment profile along the pile length for all the considered cases. This study show that single batter piles (batter angles 10° and 20°) attract the bending moments three times more than single vertical piles.