A BEM–FEM model for the dynamic analysis of building structures founded on viscoelastic or poroelastic soils

Abstract

This work presents a time–harmonic boundary element – finite element three–dimensional model for the dynamic analysis of building structures founded on elastic or poroelastic soils. The building foundation and soil domains are modelled as homogeneous, isotropic, elastic or poroelastic media using boundary elements. The foundation can also be modelled as a perfectly rigid body coupled to soil and structure. The buildings are modelled using Timoshenko beam finite elements that include the torsional eccentricity of non–symmetrical buildings. The excitation model includes far–field plane seismic waves of P, S or Rayleigh type for viscoelastic soils and P1 and S type for poroelastic soils. Modelling foundation and structure as rigid body and Timoshenko beam respectively, conveys important benefits such as a significant reduction in the number of degrees of freedom in the problem, which allows to study problems involving several building structures and the interactions between them with acceptable computational effort. Results are presented for validation purposes first, and for studying the influence of modelling the soil as a viscoelastic or poroelastic region afterwards. A study of the modelling of structure–soil–structure interaction effects is also performed.