Lower-bound calculations of the bearing capacity of eccentrically loaded footings in cohesionless soil

Abstract

Lower-bound calculations based on the finite element method are used to determine the bearing capacity of a strip foundation subjected to a vertical, eccentric load on cohesionless soil with varying surcharges. The soil is assumed perfectly plastic following the Mohr–Coulomb failure criterion. The results are reported as tables and graphs showing the bearing capacity as a function of the eccentricity and surcharge. Normalised interaction diagrams in the vertical force versus moment plane have been produced. The results from the analysis are in reasonable agreement with existing methods for smaller eccentricities, whereas for greater eccentricities (e > 0.25B–0.3B, where B is the width of the foundation), the lower-bound values in general — and especially for greater surcharges — are considerably smaller than the bearing capacities predicted by existing methods. For the special case of no surcharge, the results are in very good agreement with results obtained by the effective-width approach originally proposed by Meyerhof.