1st Croatian Conference on Earthquake Engineering 1CroCEE 2021

Seismic isolation and supplemental energy dissipation are well-known techniques used since the 1970s. In Italy, their application in the first three decades (1970s, 1980s and 1990s) was more often in bridges than in buildings. As far as existing buildings are concerned, in Italy their use as retrofitting techniques is continuously increasing since 2003, following a series of destructive earthquakes (2002 San Giuliano di Puglia, 2009 L’Aquila, 2012 Emilia, 2016 Central Italy). Those earthquakes created the collapse of many old masonry buildings, and extensive damages to RC buildings as well, that were declared unfit for use. The guidelines for the repair of damaged buildings required not just to repair the earthquake-induced damages, but to improve the seismic behaviour of the buildings in comparison to their original undamaged state. The minimum target was a Capacity/Demand (C/D) ratio, in terms of PGA, of 0.6. Due to the very low capacity of most buildings, this target was not easy to reach with conventional retrofit techniques; that is why seismic isolation or supplemental energy dissipation have been often used. The paper describes examples of retrofit of buildings both with seismic isolation and supplemental energy dissipation. In particular, a typical procedure for inserting the isolators into existing RC buildings is described. Furthermore, the advantages of both seismic isolation and supplemental energy dissipation are described.