Abstract
Base isolation systems are nowadays largely used to protect the build environment and to avoid loss of life. While the behaviour of natural rubber bearings NRB and lead rubber bearings LRB is well-known, hybrid devices incorporating a NRB and a LRB, due to their complex behaviour, are difficult to be modeled. The authors have developed a theoretical model able to describe with high accuracy the performance during earthquakes of hybrid isolation systems, meantime permitting to determine the equivalent stiffness for all levels of horizontal loads. At the end of the paper numerical simulations give an overview about the possibilities to control the structure response by fitting some parameters of the device. Finally comparison with the behaviour of “classical” devices is performed. Keywords: rubber, neoprene, composites, base isolation, earthquake