Degradation Processes of Original and Retrofitted Masonry Buildings Subjected to the Action of Seismic Forces

On the base of the experience gained in the Umbria-Marche (Italy) 1997 earthquake, the research investigate on the architectonic and structural seismic vulnerability sources of the masonry buildings realised with non aseismic traditional techniques. Specific reference is done to the building types that are common in the hilly regions of central Italy.Using the damage analyses already performed by the authors with reference to the abovementioned earthquake, the more frequent collapse mechanisms and the corresponding activation causes are identified.With reference to the different collapse mechanisms, as related to the building characteristics,the effectiveness of alternative retrofitting techniques can be evaluated in terms of the upgraded seismic resistant capacities of the structural systems.