Confronto della prestazione sismica di strutture esistenti e di nuova progettazione

Existing building stock in Italy, as well as in many other Mediterranean countries, mostly consists of structures designed for gravity loads only, where the hazard at site would require proper seismic design. The main purpose of this study is to compare seismic behaviour of two different structures, one designed for gravity loads only, and one reflecting modern earthquake resistant design criteria. In particular, the performances of a bidimensional RC frame designed in accordance with Regio Decreto 2229 (1939) have been compared with the same frame but designed according to Decreto Ministeriale 14/01/2008, the recently released Italian seismic code. The two RC frames are characterized by the same global geometry (storey heights, bay lengths), but feature different material properties and element cross-section proportions. These differences strictly affect non-linear cyclic behaviour of the structural elements. Seismic assessment of the two frames has been carried out by non-linear dynamic analyses on a lumped plasticity model. Seismic input and hazard evaluation are those made publicly available by Istituto Nazionale di Geofisica e Vulcanologia and acknowledged by the seismic code