SOIL-STRUCTURE INTERACTION IN A RIGID REINFORCED CONCRETE BUILDING

B. Burçin Avar

(Thesis Supervisors:M. Nuray Aydınoğlu )

ABSTRACT

During the earthquake, soil deforms under the incident seismic waves and this influences the foundation and the supported structure. This induced motion of the super- structure generates inertia forces, which cause dynamic forces and moments at the base that are transmitted into the soil. Thus new deformations generate in the soil while additional waves emanate from the soil-foundation interface. In response, further dynamic displacements develop at the foundation-structure system

The main objective of this study is to examine the response of rigid 5-storey building type of structures founded on flexible soil by taking soil-structure interaction into consideration. Since the building is very rigid it is expected that the structure behaves like a solid box.

Structural analysis of the system and the evaluation of modal frequencies and mode shapes are carried out. Two assumptions are compared in this study. First one is that the response of the structure for different shear wave velocities according to the SSI by assuming that the first mode is effective in SSI and the other modes are superposed without SSI. The other assumption is that the response of the structure for different shear wave velocities according to the soil-structure interaction by assuming that the all modes of the structure are included into the SSI analysis.