Bearing Capacity of a Skirted Square Footing under Eccentric Loading in Granular Soil

Abstract

The ultimate bearing capacity of a shallow footing decreases when it is subjected to a moment in addition to a centric vertical load. A centric vertical load with a moment on a footing is equivalent to an eccentric load on the footing. The result of this is a net reduction of the ultimate and allowable bearing capacity of the footing. In a situation like this, the bearing capacity of the footing can be improved by providing a skirt around the footing. The present study provides the results of a laboratory test program of a skirted square (B × B) model footing in dense and medium-dense sand as it relates to the ultimate bearing capacity. For the tests, the length of the skirt (L) was varied as L/B = 0, 0.25, 0.5, 0.75, and 1.0. Based on the model test results, relationships have been developed to estimate the ultimate bearing capacity of a skirted footing with eccentric vertical loading from the ultimate bearing capacity of a footing without a skirt subjected to vertical centric loading.