Possible application of the Markovian renewal processes to the life-cycle assessment of deteriorating structures

The reliability of structural systems immerged into aggressive environments changes over time and, generally, proper maintenance interventions are required to achieve suitable levels of lifecycle performance. Often the damage process affecting the systems suffers of uncertainty due to the randomness involved into each environmental attach, therefore the life-cycle assessment must be based on a suitable damage modeling and on a probabilistic analysis able to model the main features of the time-variant deterioration process. In this paper, an appropriate time dependent damage modeling is applied in connection with a probabilistic analysis based on the semi-Markov theory. The rehabilitation of deteriorated structures requires the development of maintenance strategies where possible selective maintenance scenarios can be considered. In this paper, with the introduction of an appropriate condition index, some repairing strategies, applied only on members heavily deteriorated, are compared each other. The advantages of selective maintenance actions are also investigated by the economical point of view.