A Subbuteo-Inspired Rolling Isolation System for Protecting Rigid Blocks

Abstract

This study investigates a Subbuteo-inspired rolling isolation system (RIS) as an effective means for protecting rigid blocks. The block is assumed to be rigidly connected to a curved base sector, allowing it to roll back and forth freely under dynamic excitations. The intrinsic trait of the proposed isolation concept is that the rigid block is part of the isolation system, affecting its dynamical behavior by lowering the system's center of mass. Conventional RISs utilize spherical or cylindrical rolling elements between the structure and its foundation to decouple seismic forces and reduce the transmission of ground motion. These systems capitalize on the rolling mechanism's ability to convert translational motion into rotational motion, thus diminishing the acceleration and forces experienced by the superstructure. Key findings demonstrate that in the proposed isolation system this mechanism is further improved due to the lowered center of mass, which results in a significant improvement in the seismic resilience of rigid blocks. The system's ability to self-center after rotation and its inherent simplicity make it an alternative to conventional isolation methods. The study also addresses the potential limitations and challenges, including stability under large rotations and the impact of rolling resistance. Overall, this work provides a comprehensive understanding of the behavior, performance, design, and practical implementation of the new RIS, paving the way for its broader application in seismic protection strategies.