Bearing capacity of a cohesive-frictional soil under non-eccentric inclined loading

This paper applies numerical limit analysis to evaluate the bearing capacity of a strip footing, subjected to a non-eccentric inclined load, resting on a ponderable cohesive-frictional soil. Accurate lower and upper bounds are calculated rigorously using finite elements and nonlinear programming. By adopting typical values for the friction angle, the inclination angle, and a dimensionless parameter related to the self-weight, most cases of practical interest are treated. The results are presented in the form of tables. As the gap between the bounds does not exceed 3%, the average limit load provides a good estimate of the exact ultimate load and can be used with confidence for design purposes. The numerical results are compared with ultimate loads predicted by the theories of Meyerhof, Hansen and Vesic. The comparison shows that the Meyerhof and Vesic theories results are unconservative for inclined loading. In particular, the inclination factors from the Meyerhof theory appear to be inaccurate, whilst the Vesic theory does not take proper account of the self-weight. For a ponderable soil under vertical or inclined loading, the collapse mechanism from the rigorous upper bound analysis is different to that assumed by previous authors. (C) 2004 Elsevier Ltd. All rights reserved.