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The dynamic through-soil interaction between nearby pile supported structures in a viscoelastic half-space, under incident S and Rayleigh waves, is numerically studied. To this end, a three-dimensional viscoelastic BEM-FEM formulation for the dynamic analysis of piles and pile groups in the frequency domain is used, where soil is modelled by BEM and piles are simulated by one-dimensional finite elements as Bernoulli beams. This formulation has been enhanced to include the presence of linear superstructures founded on pile groups, so that structure-soilstructure interaction (SSSI) can be investigated making use of a direct methodology with an affordable number of degrees of freedom. The influence of SSSI on lateral spectral deformation, vertical and rotational response, and shear forces at pile heads, for several configurations of shear one-storey buildings, is addressed. Maximum response spectra are also presented. SSSI effects on groups of structures with similar dynamic characteristics have been found to be important. The system response can be either amplified or attenuated according to the distance between adjacent buildings, which has been related to dynamic properties of the overall system.

In this paper, a 3D BEM-FEM coupling model is used to study the dynamic behavior of piled foundations in elastic layered soils in presence of a rigid bedrock. Piles are modelled by FEM as beams according to the Bernoulli hypothesis, and every layer of the soil is modelled by BEM as a continuum, semi-infinite, isotropic, homogeneous, linear, viscoelastic medium. First, the main points of the model are set out. Then, several results of vertical, horizontal and rocking impedances for single piles and 2 × 2 pile groups embedded in a stratum resting on a rigid bedrock, are presented. The influence on the dynamic response of stratum depth, soil stiffness and piled foundation configuration is discussed. Finally, the influence of the stratigraphy on the seismic response of a 3 × 3 pile group is analyzed, together with the pile-to-pile kinematic interaction and the wave-scattering phenomena.

The influence of inclined piles on the dynamic response of deep foundations and superstructures is still not well understood and needs further research. For this reason, impedance functions of deep foundations with inclined piles, obtained numerically from a boundary element -finite element coupling model, are provided in this paper. More precisely, vertical, horizontal, rocking and horizontal-rocking crossed dynamic stiffness and damping functions of single inclined piles and 2 2 and 3 3 pile groups with battered elements are presented in a set of plots. The soil is assumed to be a homogeneous viscoelastic isotropic half-space and the piles are modeled as elastic compressible Euler-Bernoulli beams. Results for different pile group configurations, pile-soil stiffness ratios and rake angles are presented.