New Subgrade Model Applied to Mat Foundations

Abstract

A new mathematical model for analyzing mat foundations under static loading is developed based on Reissner's concept of a simplified elastic continuum. Horizontal normal and shear stresses are assumed to be zero throughout an elastic layer of finite thickness. The relationship between applied surface pressure and settlement is defined by a single differential equation that can be solved readily using finite differences. Coefficients in the differential equation are functions of the elastic parameters and thickness of the layer only. Solutions for a Young's modulus constant with depth, as well as varying lin early and with the square root of depth, are discussed. The Reissner Simplified Continuum is shown to offer substantially better correlation with exact theory of elasticity solutions than does the commonly used modulus of subgrade re action (Winkler) model.