Seismic safety evaluation of historical centres

After recent seismic events, the topic of seismic prevention and mitigation in historical centres is becoming very important, in particular for seismic prone areas, like Italy, Greece, Portugal, in which a lot of historical towns, for the high quantity of old buildings and for their urban structure, suffered from significant damages. For this reason, this study deals with a new strategy for the seismic prevention and mitigation of historical centres, analyzing them in terms of structural safety. The proposed approach is based on two relevant steps: the first is to study the Urban Risk, the second is to program the Post-Earthquake Activity. The first activity consists in the analysis of a complex system aiming at individuating the nodal fragility, the second tends to evaluate the buildings safety and the occupancy conditions for these buildings. In this paper a particular aspect of this topic is discussed, i.e. how different typologies of buildings, that coexist in historical towns, could influence the reconstruction strategy. In fact, the term “old buildings” surely include masonry historical building, but also includes more recent r.c. buildings designed without any seismic provisions or, as unfortunately usual, realized with poor quality material. Considering that in recent seismic events often this class of buildings caused many damages and deaths, an efficient procedure able to measure the impact of r.c. structures on seismic prevention and mitigation in historical centres has to be considered a fundamental goal to reach.