Numerical investigation of the main factors influencing rocking responses of shallow foundations

Abstract

Several investigations have shown that structures with rocking foundations bring more stability and fewer instances of post-earthquake damage to superstructures by dissipating seismic energy within the underlying soils. Nevertheless, there are still obstacles to making this design philosophy a practical solution, including concerns about the residual settlements and rotations. In order to provide a better insight into the problem, the present paper investigates the performance of a simple structure with a rocking foundation, taking advantage of pushover and time history analyses. The finite-element method is applied for the study, and the numerical model has been validated using results from recent experimental research. Accordingly, the effect of a number of influential parameters involving the properties of soil, structure and ground motions is evaluated. The current research considers different static safety factors against soil shear strength failure, structure slenderness ratios, earthquake records and foundation embedment depths, and the response of the systems with rocking foundations has been elaborated using the results obtained. The contribution of the investigated parameters is pronounced in the main features of the rocking foundation performance, such as the system moment capacity and foundation deformations (settlement and rotation).