Analytical plasticity-based model for soil-structure interaction of lumped system on heterogeneous soil media

In the present study, an analytical approach is developed for the soil-structure interaction for the linear, eq. linear and elastic-perfectly plastic layered soil strata. The amplification factor is calculated at the top of a lumped structure incorporating layered soil, foundation, and super-structure deformation. The equation of motion of the system under the normalized earthquake excitation is solved using the direct integration method. MATLAB script is developed to carry out the parametric study, and nonlinear time history analysis is performed. The present methodology is compared with the finite element model (FEM), which shows good agreement. The computational time is much less than the FEM method. A parametric study is carried out in terms of soil heterogeneity, mass ratio, slenderness ratio, excitation frequency, and material model. The results indicate that due to the heterogeneity of the soil, the response of the structure is increased significantly; with the increase in the mass ratio, the amplification factor decreases with excitation frequency up to resonance, and the effect of mass ratio is negligible at the higher frequency range; with the increase in slenderness ratio, the amplification factor increases up to resonance, however, at higher frequency ranges there is no effect of slenderness ratio. The results indicate that due to the heterogeneity of the soil, the response of the structure is increased significantly; with the increase in the mass ratio, the amplification factor decreases with excitation frequency up to resonance, and the effect of mass ratio is negligible at the higher frequency range; with the increase in slenderness ratio, the amplification factor increases up to resonance however at higher frequency range there is no effect of slenderness ratio. image