The Effect of Foundation Shape on Subgrade Reaction Coefficient

Abstract

This paper numerically examines the effect of foundation shape on the subgrade reaction coefficient. The distribution of the subgrade reaction coefficient on the foundation area and the values of this coefficient in different regions are studied. A method is also introduced to determine the subgrade reaction coefficient of unusually shaped foundations sometimes encountered in practice. It has been shown that it is possible to divide the foundation area into several regions, and the subgrade reaction coefficient of each part is a multiplier of the central point reaction coefficient. The reaction coefficient of a trapezoidal foundation is equal to the reaction coefficient of a rectangular foundation with a similar area, and the length of the rectangle is the same as the height of the trapezoid. Also, the settlements of two foundations are equal. An L-shaped foundation’s reaction coefficient is a product of multiplying the reaction coefficient of a rectangular foundation to a ratio of the rectangular area by an L-shaped area if the settlements of the two foundations are equal. Besides, the reaction coefficient of a ring-shaped foundation is a product of multiplying the reaction coefficient of a circular foundation with the same outside diameter by the ratio of the circular area to the ring area if the settlements of both foundations are the same.