Elastic settlement of square footings on a two-layer deposit

Abstract

Two charts for elastic (immediate) settlement at the centerline of a flexible square footing on Burmister two-layer elastic system are presented in this paper. The charts are developed for different values of the modular ratio E1/E2 [where E1 refers to the modulus of elasticity of the first (top) layer and E2 corresponds to the second (bottom) layer] and relative layer thickness h/B (where h refers to the first layer's thickness and B to the side length of square footing ). The first chart is devoted to the case of a soft top layer on a stiffer bottom layer, while the second chart is for a stiff top layer over a softer bottom layer. The analytical solution for surface deflection was based on Burmister analysis and extended to the case of square footings. The paper reveals that the surface settlement at centerline decreases with increasing modular ratio for E1/E2 >1 and it increases with decreasing modular ratio for E1/E2 < 1 especially for the higher values of h/B.