Dynamic Performance of Model Rocking Footings on Sand Reinforced by Soil-Cement Columns

Abstract

This study focuses on the load-deformation response of a heavily loaded rocking footing on sand reinforced by soil-cement columns via centrifuge-model scale shake table tests. In a previous study involving the same footing on unimproved ground, the footing exhibited overturning failure and excessive settlement. To mitigate this, the present study aims to control the kinematics of the footing via strategic ground improvement while maintaining the enhanced energy dissipation characteristic of a rocking footing. The ground improvement technique consists of soil-cement mixed columns which were cast externally and then placed in the model sand layer during pluviation. Shake sequences are applied to both determine the frequency response of the soil-structure system as well as to induce controlled yielding in the improved soil. The addition of paired soil-cement columns at the ends of the footing was found to significantly reduce settlement during rocking and preserve re-centering throughout demanding shaking events.