A 3-DOF system for preliminary assessments of the interaction between base isolation (BI) technique and soil structure interaction (SSI) effects for low-rise buildings

Abstract

Base isolation technique is based on two mechanisms: period elongation and damping increase that may considerably improve the structural performance under earthquakes. However, the effectiveness of BI may be significantly reduced by the deformability of the foundation soil and thus by soil structure interaction (SSI) effects. In this regard, considering the role of the mutual interaction between BI and SSI becomes fundamental to realistically design structural systems. In literature, the assessment of the mutual role of BI and SSI is conducted with advanced numerical simulations that require realistic definitions of the non-linear properties of the structures, the isolation system and of the soil layers. However, these methods are extremely time-consuming and more expeditious methodologies are necessary. In this paper a 3-DOF system is proposed to perform preliminary assessments for design purposes. Parametric case studies have been proposed to demonstrate the potentiality of the proposed method to represent the cases where the beneficial effects of BI are reduced and eventually when BI technique becomes detrimental.