Shape Factors for Limit Loads on Square and Rectangular Footings

Earlier proposals for shape factors used in calculations of bearing capacity of square and rectangular footings are examined. These proposals are based on empirical data for small footings, whereas a new suggestion for these factors presented in this paper is based on the elasto-plastic model of the soil and finite element analysis. The earlier factors modifying the contribution of cohesion and overburden were found to be conservative, but acceptable in design. However, the earlier proposals for the shape factor that affects the contribution of the soil weight to the bearing capacity indicate contradictory trends, and the factor calculated in this paper is suggested as an alternative.