Simplified BEM/FEM model for dynamic analysis of structures on piles and pile groups in viscoelastic and poroelastic soils

A simplified model for the analysis of the dynamic response of structures on piles and pile groups under time harmonic excitation is presented in this paper. It is a coupled boundary element–finite element model able to take into account dynamic pile–soil–pile interaction in a rigorous manner. Piles and pile groups in viscoelastic or poroelastic soils are considered. Two-node cylindrical boundary elements are used to represent the interface between soil and pile. These elements are connected to beam-type finite elements representing the concrete pile which can be connected to a pile cap and to any superstructure modeled by beam elements. The model is rather simple: two-node beam elements along the pile are directly connected to the BE nodes along the soil hole, and the uppermost node to the soil surface and to the FE nodes of any superstructure. Thus, large structures founded on piles in viscoelastic or poroelastic soils can be represented using a reasonable number of unknowns. In order to validate the procedure, single piles and pile groups in viscoelastic and poroelastic soils are analyzed. The obtained results are compared with those obtained by other authors using more complex or less general approaches. There is a good agreement between the present results and those reported in the literature.