ABSTRACT
Most SI systems rely on the use of rubber bearings (RBs), namely High Damping natural Rubber Bearings (HDRBs), Neoprene Bearings (NBs), Lead Rubber Bearings (LRBs), or (mainly in
1 INTRODUCTION
Over 16,000 structures in the world have been protected by anti-seismic (AS) techniques, namely by seismic isolation (SI) or energy dissipation (ED) systems, shape memory alloy devices (SMADs), or shock transmitter units (STUs) (Dolce et al., 2006, Martelli 2010, Martelli & Forni 2010 & 2011a, b, Martelli et al., 2008 & 2011a, b, c, Sannino et al., 2009). They are located in more than 30 countries (Fig. 1) and concern both new constructions and retrofits of existing structures of all kinds: bridges and viaducts, civil and industrial buildings, cultural heritage and industrial components and installations, including some high risk nuclear and chemical plants. They are made of all types of materials: reinforced concrete (r.c.), steel and even wood.
