Implementation of the consistent lumped-parameter model for the computation of the seismic response of nonlinear piled structures

Abstract

The computation of the nonlinear response of piled structures taking soil-structure interaction into account is tackled in this paper. The structure is assumed to be founded on a group of piles, whose impedance and kinematic interaction functions are computed, in the frequency domain, through a boundary elements-finite elements coupled formulation. On the other hand, the response of the system is computed using a time-stepping procedure for the integration of the equations of motion for an inelastic superstructure, which requires a time-domain representation of the above-mentioned impedance and kinematic interaction functions. This can be achieved by the use of different methodologies, such as standard lumped-parameter models, higher-order consistent lumped-parameter models, or hidden state variable models, among others. In this paper, the use of high-order consistent lumped-parameter models for the deterministic representation of the impedance functions of deep foundations will be discussed together with different aspects of the resulting equivalent systems such as degree of accuracy, physical representation of parameters or arising numerical stability issues. Then, the use of this approach for the computation of the inelastic response of piled structures subject to seismic excitation will be explored.