Base Isolators

This chapter describes the main seismic isolators, starting with the definition given by European standards. High-energy dissipation rubber supports, rubber-lead insulators, and sliding pendulum insulators are taken into consideration. A brief description is given of each of them, also referring to their history, and the mathematical model that must be used to design the structures is provided. For the sliding pendulum isolators are given criteria to facilitate the selection of the right one: with simple or double sliding surface, with or without central articulation. Ample space is also dedicated to the sliding materials that are used in sliding pendulum insulators; in fact, they are the most important component of these devices. Their requirements and the test methods to demonstrate their suitability are described. A comparison is also made between the properties of rubber insulators and sliding pendulum insulators, highlighting the pros and cons of the two types.