The role of overstrength in damage propagation and monitoring of architectural heritage

The protection and structural retrofitting of architectural heritage are fundamental issues for both modern architects and structural engineers and require a great combined effort of different skills. Historical constructions accumulate damage during their lifetime due to materials deterioration, repeated loads and exceptional events. In this sense, it is important not only to evaluate the safety of these structures under traditional loads, but also their structural response to propagation of damage. Thinking about robustness, indented as the capacity of a structure not to be too sensitive to local damage, whatever the source of damage, in the present paper a methodology able to increase the robustness of historical structures is proposed. The paper aims at evaluating the contribute of an additional strength (i.e., overstrength) in the retrofit of key structural members and in the development of several collapse resisting mechanisms of the whole construction. The procedure proposed in the presented paper suggests a strategy that is suitable for monitoring an historical construction, considering the effects of overstrength in damage propagation.