Nonlinear Dynamic Analysis of Pile Foundation Subjected to Strong Ground Motion Using Fiber Elements

In this paper, pile behavior embedded in layered soil deposits subjected to seismic loadings is analyzed using a nonlinear fiber element for simulation of soil – pile interactions. In the created model, both pile and surrounding soil are modeled using fiber elements in a practical Beam on Nonlinear Winkler Foundation (BNWF) concept. Herein, the features of DRAIN–3DX finite element software are utilized in order to develop the model. In the presented approach for performing of Seismic Soil-Pile-Superstructure Interaction (SSPSI) analysis, the constitutive behavior of soil and steel pile are assigned to fiber elements using available soil p-y backbone curves and steel stress-strain relationship. The effect of radiation damping is incorporated into the model by adding a dashpot in parallel with nonlinear p-y element. In order to consider the effects of free field site response in different soil layers, EERA and NERA programs are used. Results of the analyses are compared with available experimental data. The results are in good agreement with the available centrifuge test results. The main purpose of the proposed method is to make DRAIN–3DX software capable of performing SPSSI analysis of any pile supported structure especially Jacket Type Offshore Platforms (JTOP).