Influence Of Soil Characteristics On Seismic Response Of Mid-rise Moment Resisting Buildings Considering Soil-Structure Interaction

Behzad Fatahi, Hamid Reza Tabatabaiefar and Bijan Samali

In this study, a fifteen storey moment resisting building frame, representing the conventional types of regular mid-rise building frames, resting on a shallow foundation, is selected in conjunction with three soil types with the shear wave velocity less that 600m/s, representing classes Ce, De and Ee, according to AS 1170.4. Characteristics of the employed soils have been extracted from the available geotechnical investigation reports of various projects. Furthermore, the structure is modelled considering the three mentioned types of the subsoil medium underneath employing the Finite Difference approach using FLAC 2D software. Three strong ground motion records adopted by the international community as benchmark earthquakes are used. These are the 1968 Hachinohe, the 1995 Kobe and the 1994 Northridge earthquakes. Fully nonlinear dynamic analysis under influence of different earthquake records is conducted, and the results of the three different cases are compared and discussed. The results indicate that the dynamic properties of the subsoil play a significant role in seismic response of the building frames under the influence of soil-structure interaction. As the shear wave velocity of the subsoil decreases, lateral deflections and inter-storey drifts of the structures increase which can change the performance level of the structures from life safe to near collapse or total collapse.