Seismic Design Aids for Buildings Incorporating Soil-flexibility Effect

Abstract

The effect of soil-structure interaction is generally ignored in the design process of low-rise buildings resting on shallow foundations though it has been shown that ignoring such effect may lead to unsafe seismic design. In the present paper, the effect of soil flexibility on base shear and uncoupled torsional-to-lateral natural period ratio, two crucial design parameters in the elastic range, is examined in a comprehensive manner. Variation of such quantities with different influential parameters has been studied considering the effect of soil-flexibility. Apart from reiterating the need significance of soil-flexibility effect for safe seismic design, a large number of rationally derived curves have been presented to incorporate this effect in seismic design with ease and convenience. The exhaustive range of case studies encompassed through such curves may be useful to the designers to easily account for such effect for most of the practically encountered low-rise buildings if needed, through interpolation. Furthermore, the trend observed in such soil flexibility effect is also highlighted to provide physical insight into the issue.