Quantification of seismic mitigation performance of periodic foundations with soil-structure interaction

This paper investigates the influence of soil-structure interaction (SSI) on the seismic mitigation performance of a periodic foundation (PF) on vertically propagating shear waves. Two different mechanical models are employed to compare seismic responses of controlled and uncontrolled superstructures: i) the first one for the PF-controlled system, which is based on the Winkler approach and where the PF is treated as a shear frame; ii) the second one for the uncontrolled superstructure, which is based on the cone model. These two models are verified by comparison against the results of two-dimensional finite element models. Based on the mechanical models, the PF is optimized considering SSI. Then, the impact of SSI is investigated by comparing responses of the controlled and uncontrolled superstructures in both the frequency and time domains in two different soil types, respectively. Relevant results show that the PFs' performance can benefit from SSI. The robustness of PFs is improved and less damping is needed in resonators, both of which improve PFs' feasibility.