Behavior of confined square and rectangular footings under eccentric-inclined load

Abstract

This paper presents the results of laboratory model tests on the effect of soil confinement on the behavior of square and rectangular model footings resting on Ganga sand under eccentric - inclined load. Confining cells with different heights and widths have been used to confine the sand. The studied parameters include the cell height, cell width and the depth from base of footing to the top of the confining cell, load eccentricity and load inclination. The ultimate bearing capacity improvement due to the soil confinement is represented using a non-dimensional factor, called the bearing capacity ratio (BCR). The results indicate that the ultimate bearing capacity of footings can be appreciably increased by soil confinement under axial load as well under eccentric-inclined load. It has been observed that such confinement resists the lateral displacement of soil underneath the footing leading to a significant decrease in the vertical settlement and hence improving the ultimate bearing capacity. For small cell width, the cell-soil footing behaves as one unit (deep foundation), while this pattern of behavior was no longer observed with large cell width. The recommended cell heights, depths, and widths that give the maximum ultimate bearing capacity improvement are presented and discussed.