Features, recent application and conditions for the correct use of seismic isolation systems

摘要

Over 16,000 structures have been protected in the world by seismic isolation (SI) and other anti-seismic systems. Such structures are located mostly in Japan, but they are more or less numerous in more than 30 other countries, including Italy (which is now fourth at worldwide level for the number of isolated buildings, after Japan, China and the Russian Federation). Application of SI is increasing everywhere, although its extent is strongly influenced by earthquake lessons and the features of the design rules used. It concerns both new and existing structures of all kinds. This paper provides a short overview on its recent progress worldwide and on the behaviour of seismically isolated buildings during recent earthquakes, based on the most recent information available to the authors (including some preliminary data on the effects of the 2011 Christchurch and Tohoku events). Particular attention is paid to the isolated buildings in Italy, in the context of the effects of recent quakes (2002 Molise and Puglia and 2009 Abruzzo events). Based on the Italian experience, some important conditions for the correct use of the anti-seismic systems are also stressed in the Conclusions.