A Markovian-based methodology for the life-cycle cost analysis of bridge maintenance interventions under changing deterioration rates

Markovian transition probability matrices employing condition states are often used in bridge management systems to determine optimal intervention strategies. This approach assumes a constant deterioration matrix throughout the entire analysis period. In addition, decisions to carry out interventions are normally based on deterioration to predefined condition states, which are generally not linked to structural safety. However, in order to adequately model and evaluate certain intervention options, such as fiber-reinforced polymer (FRP) strengthening, it is necessary to model the impact of the intervention on the deterioration rate, as well as the safety of the structure. This paper presents a Markovian approach to model interventions that impact deteriorating rates. A model employing this approach is proposed, which also accounts for the safety of the structure. A simplified methodology to determine the optimal intervention strategy based on steady state probabilities is also presented. The proposed model and methodology are illustrated in a hypothetical bridge example, where one of the interventions is FRP strengthening of a concrete girder bridge.