Key Parameters to Model the Mutual Effects Between Base Isolation (BI) and Soil–Structure Interaction (SSI)

The mutual interaction between base isolation (BI) and soil–structure interaction (SSI) needs to be considered in design applications. In the literature, the key parameters that may affect such interaction have been rarely considered. Closed formulations for the assessment of the mutual role of BI and SSI have not been proposed yet. The paper aims to cover this gap by considering a 3DOF model to propose closed relationships with the most significant parameters (structural period, isolation ratio and shear wave velocity). The outcomes show that there are two different interactions. When soil deformability and structural stiffness are not significant, the isolation ratio may be used as a main parameter. However, when the foundation soil is particularly deformable and structures are significantly rigid, a more complex relationship needs to be considered. Parametric case studies have been performed with different structures, three isolation ratios and several soil conditions (soil A, B, C and D).