SEISMIC BEARING CAPACITY OF FOUNDATION ON COHESIONLESS SOIL

The seismic bearing capacity of a strip-surface foundation resting on a Mohr-Coulomb material is evaluated. The upper-bound theorem of the y ield design theory is used to obtain an estimate of the ultimate load, The loading parameters consist of a normal and tangential force appli ed to the foundation and of inertia forces developed within the soil v olume. The classical Prandtl-like mechanism is used to show that the r eduction in the bearing capacity is mainly caused by the load inclinat ion; the consideration of inertia forces within the soil is only respo nsible for a decrease in the bearing capacity that is at least an orde r of magnitude smaller than the one caused by the load inclination. It is therefore concluded that, from a practical engineering standpoint, the soil-inertia forces can be neglected.