Dynamic response of shallow strip foundations on a non-homogeneous stratum

Abstract

The steady-state dynamic response of rigid strip footings is studied using a simplified method. In this method, a bounded medium represented by two equations is formed. This bounded medium with proper boundary conditions can represent any soil layer. Inhomogeneity of the soil layer is incorporated in the formulation by introducing a layered soil medium with linear variation of shear modulus. The final expressions developed for the response of foundations are found in simple closed forms. The computation requires iterations which are found to generally converge within very few iterations. The developed formulations are demonstrated for both surface and embedded foundations in a nonhomogeneous soil stratum overlying a rigid base. The results of the dynamic stiffness and flexibility functions for both homogeneous and nonhomogeneous soil layers are compared with available published results and they show good agreement. Despite considerable simplifications, the developed formulations produce results that are very close to those computed by much more elaborate methods.