Evolution of damage on historical heritage buildings in presence of catastrophic events and aggressive natural phenomena

The feasibility analysis of projects for the preservation of the historical heritage buildings is an important problem concerning the evaluation of “the total cost of intervention”, which includes all the future damage costs. The total cost of intervention represents a suitable measure of the expected deterioration risk and its evolution obviously depends on the damage process which buildings are subjected to. That damage phenomena affecting masonry buildings pleased into an aggressive environment are suitably modelled by renewal processes: this happens both in the case of catastrophic events, or in the case of the so-called “natural aging”, in which damage comes off gradually in time. In the hypothesis of a Markovian renewal process describing the damage process, the total cost of all the future damage is evaluated taking into account both the damage aspects: damages due to catastrophic aspects and damages due to aggressive environment, supposing different maintenance and/or rehabilitation scenarios. A semi-Markov process is defined to model the damage rehabilitation history of buildings in presence of seismic events, natural ageing and rehabilitation strategies. The expected rewards connected to the process are defined; they represent a significant measure of the risk.