Abstract: With a linear Mohr-Coulomb failure criterion, an estimate of bearing capacity of a strip footing resting on a homogeneous and isotropic geomaterial foundation had been made using the methods of limit equilibrium, characteristics line and limit analysis in the previous literature. However, experimental data have shown that the strength envelopes of almost all geomaterials have the nature of nonlinearity. In this paper, a nonlinear failure criterion is employed to evaluate the bearing capacity of a strip footing using the upper bound theorem of limit analysis. A generalized tangential technique is presented to formulate the problem of bearing capacity as nonlinear programming problem. The optimum solution is obtained by a nonlinear sequential quadratic programming algorithm. From the numerical results, it can be seen that the nonlinear failure parameter has a significant effect on the bearing capacity; and that the solutions presented in this paper agree well with previous results if the nonlinear failure criterion is reduced to a linear Mohr-Coulomb failure criterion.

Key words: bearing capacity, upper bound theorem, nonlinear failure criterion