Seismic Isolation Devices Based on Sliding between Surfaces with Variable Friction Coefficient

Abstract

Base isolators are effective tools to favor a high level of building performance under lateral load, providing protection to both structural and nonstructural elements. In this context, this paper discusses the possibility of employing materials with different frictional properties to enhance the response of flat and curved-surface base isolators. Two innovative devices, referred to as “BowTie” and “BowC,” are introduced and discussed in some detail. A series of nonlinear time history analyses are then conducted using a customized computer program and considering a number of case study structures, designed applying a displacement-based approach. The results of the analyses are used to discuss the key differences between variable friction and constant friction sliding isolation devices. It is shown that the newly proposed isolators may represent an improvement on classic base-isolation solutions, in light of their higher energy absorption capacity, which contributes to significantly enhance their performance.