Numerical Study of Shallow Rocking Foundations Under Seismic Excitation and Lateral Monotonic Loadings

Recent studies have shown that the rocking of foundations and the yielding of soil can decrease the load transmission to a superstructure during earthquakes. However, more investigations should be carried out to make this design philosophy a practical solution among seismic engineers. The research presented applies the finite element method to study the response of single-degree-of-freedom systems constructed on soils of medium density with rocking foundations prone to lateral monotonic and ground motion loadings. Various dynamic analyses were performed in order to explore the role of two influential parameters, i.e., the static safety factor versus the soil’s bearing capacity failure and the structure’s slenderness ratio, in the performance of a soil-foundation system and the structure’s stability. A comparison of the system’s behavior for the two loading cases is also presented. According to the results, the geometric nonlinearity (the foundation’s detachment from the underlying soil) and the material nonlinearity responses are evident from the analyses. Also, the dominant role of the foundation’s safety factor versus the vertical loads in the system’s performance has been found to be indisputable.