Buildings are susceptible to soil structure interaction effects due to the
induced changes in the dynamic characteristics of soil during seismic
excitation; particularly several buildings have been constructed on soft
soil. Because of this detrimental effect, this paper aims at clarifying the
soil structure interaction effect on the seismic response of buildings
under strong ground motions to provide damage control and enhance the
safety level of such buildings. An iterative dynamic analysis was
performed using SAP2000 program to carry out three dimensional time
history analysis of non-linear soil-foundation-building models under a
great earthquake ground motions. The interaction between the soil and
structure is represented by Winkler spring model and the damping effect
of the soil is modeled by dashpots. The coefficients of springs and
dashpots were based on medium soil profile underneath and along the
embedded depth of foundation and calculated as recommended by
Newmark and Rosenblueth 1971 [23].
A comparison of response for different building models subjected to
three dimensional great earthquake ground motion shows that
incorporating the soil structure interaction could have a detrimental
effect on the building performance and overestimates the top < br />displacements response. On the contrary flexible bases of buildings have
noticeable effect on the structural behavior of buildings by providing
pronounced reduction in the internal forces of superstructure response
compared to the fixed base buildings. Also, the obtained results
confirmed that the dynamic characteristics of soil structure system
should be recommended for conservative nonlinear seismic response of
the high building since it mitigates of earthquake hazards.