A 3D IBEM-FEM coupling model for time-harmonic soil-structure inter- action analysis

Resumo

This work presents a numerical model for the analysis of arbitrarily-shaped 3D structures, under time-
harmonic loading, supported by the soil surface. The structure is modeled with the finite element method, and the

soil is modeled by the indirect boundary element method. The present formulation uses superposition of Green’s
functions for loads distributed over rectangular areas to obtain stress and displacement fields anywhere in the
soil. The use of a boundary element-based formulation makes this model capable of representing accurately wave
propagation in the soil and of complying with Sommerfeld’s radiation condition, and avoids truncation problems
and computational cost issues that would result from different methods. Coupling between the elements of the
structure and of the soil is established by imposing equilibrium and continuity conditions at their interface. This
results in an equation of motion of the soil-structure system, written in terms of nodal displacements and forces of
the structure, and involving the effect of soil flexibility. A representative example of a tower interacting with the
soil is analyzed.