Effects of nonlinear dynamic soil structure interaction on the response of buildings

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A matlab computer program for numerical modeling is proposed for the prediction of soilstructure interaction effects on structures due to wave propagation. a hybrid finite element formulation based on pseudo-spectral methods, that is spectral finite element method (sfem) is used to describe the wave through soil propagation in buildings. the modeling of the soil represents the key feature of the prediction model. both direct and substructure methods are applied to model the soil structure system, where the soil is supposed as horizontally layered visco-elastic or mohr-coulomb half-space for which the nigorous green's functions are derived. nonlinearities of the superstructure and at the interface between the foundation and the soil are taken into account. based on an indirect boundary integral method, the dynamic stiffness matrix of different foundation types at the surface of the layered half-space is calculated. this frequency dependent relation, between the structure-soil interaction forces and the displacements of the foundations, transformed to a recursive evaluation of the forces in the time domain. this time domain analysis enables the prediction model to account for non-linear behavior in a further stage of the research. based on the green's functions of the layered half-space, the spectral density of the ground-borne vibrations is predicted. the applications of the thesis demonstrate the importance of the accurate and consistent soil model both for the evaluation of the structure-soil interaction forces as well as for the prediction of the ground-borne vibrations. the prediction model is applied to identify parameters that have a large impact on the generation and the propagation of vibrations due to seismic waves.