Soil inertial factors for seismic bearing capacity

Earthquake loadings can reduce the ultimate bearing capacity of shallow foundations due to the imposition of transient horizontal loads and moments arising from the inertia of the supported structure, inertial forces in the soil mass and strength reduction in the founding materials due to rapid cyclic loading. In this paper, the general bearing capacity equation is used to calculate the seismic bearing capacity of shallow foundations. To account for the effect of inertial forces in the soil mass, soil inertial factors for level and sloping ground are recommended and their significance to the seismic bearing capacity is assessed. This paper provides a straightforward method to calculate seismic bearing capacity for the seismic design of shallow foundations within the limitations of pseudo-static analysis.