Evaluation of the impact of soil-structure interaction on seismic response of reinforced concrete frame building

摘要

The thesis deals with an impact of the deformability of the soil on the seismic response of an eight storey reinforced concrete frame building during earthquake. The response of a structure with fixed base was compared to the response of a structure with consideration of soil-structure interaction. The soil-structure interaction was modelled in three different ways. In addition to the simple model with springs and dampers, which taken into account the modulus of soil reaction, the soil-structure interaction was modelled also by the linearly elastic finite elements and nonlinear finite elements. The dynamic analysis was performed using three accelerograms whose spectrum corresponded to the elastic spectrum defined according to Eurocode 8. Models were developed in program SAP2000 and Plaxis. The results were analysed in terms of storey shear forces and in storey displacements. Relative displacement in relation to the ground were greater if the soil-structure interaction was considered in the analysis. The increment of displacement is a consequence of the rotation of the structure as a rigid body due to deformation of soil. However, consideration of soil-structure interaction reduced the storey shear forces. The results when the soil was modelled by the springs and dampers were similar to udthose obtained in the case of nonlinear material model of the soil. For other models, where the soil was modelled by the linear elastic finite elements, the results were quite different, and probably incorrect, since the behaviour of the soil is nonlinear even at very small strains.