Seismic performance of circular foundations resting on stone columns

ABSTRACT: Circular foundations are mainly used in projects such as liquid storage tanks, bridge piers, and silos. One of the main challenges in designing circular foundations is to control the foundation settlement, uplift, and slide, especially when the foundation is resting on loose granular soils and subjected to seismic loads. One way to reduce the displacements is to use stone columns below the foundation. Therefore, the main objective of this study is to investigate the influence of stone columns on the seismic performance of circular foundations through a parametric numerical study and to provide insights regarding these parameters for real world engineering projects. Abaqus software is used to simulate the multilateral interactions between superstructure, foundation, natural stratum, and stone columns. The parameters considered in the analyses include the length, diameter, and center to center spacing of the stone columns. The role of these factors on foundation settlement, uplift, and slide under seismic loads is presented and discussed. The results reveal that increasing the length of the stone columns up to a threshold value can decrease the settlements, but only marginal influence can be observed beyond that value. More importantly, the stone column's diameter and spacing play a more critical role than its length in decreasing the displacement due to seismic loads. In addition, the parameters related to stone columns may not reduce settlement and uplift to the same extent.