Evaluation of the Seismic Bearing Capacity of Shallow Foundations Located on the Two-Layered Clayey Soils

Abstract

The seismic bearing capacity of shallow strip footings located on homogeneous soils is studied extensively. But the effect of building height and layering is not included in those studies. In this paper two-layered cohesive soils are studied along with building height effect. The formulation of the problem is derived by extending the limit equilibrium method developed by Merlos and Romo (J Soil Dyn Earthq Eng 26(2):103–114, 2006) for two-layered soils. A log-spiral potential failure surface is assumed, and the inertia forces are applied directly to the building and the failure block soil mass. The position of the failure surface is obtained by a minimization process for every earthquake shaking acceleration. Results show that the potential failure surface moves upward and its length shortens as the peak ground acceleration (PGA) increases, reducing the bearing capacity. Also, the effects of building height, PGA, ratio of cohesion of the layers and the thickness of the top layer on seismic bearing capacity factor (Nce) are studied.