Evaluation of expected life-cycle maintenance cost of deteriorating structures

In a world where financial resources do not keep pace with the growing demand for maintenance of deteriorating structures, it is imperative that those responsible for maintenance decisions make the best possible use of limited financial resources. Decision makers have to evaluate the expected life-cycle maintenance cost of deteriorating structures and use benefit/cost techniques for finding the optimal resource allocation. This paper proposes a methodology for the evaluation of expected life-cycle maintenance cost of deteriorating structures by considering uncertainties associated with the application of cyclic maintenance actions. The methodology can be used to determine the expected number of maintenance interventions on a deteriorating structure, or a group of deteriorating structures, during a specified time horizon and the associated expected maintenance costs. The method is suitable for application to both new and existing civil infrastructures under various maintenance strategies. The ultimate objective is to evaluate the costs of alternative maintenance strategies and determine the optimum maintenance regime over a specified time horizon. In its present format, the first line of application of the method is for highway bridges. However, the method can be used for any structure, or group of structures, requiring maintenance in the foreseeable future. The proposed method can be programmed and incorporated into an existing software package for life-cycle costing of civil infrastructures. An existing reinforced concrete bridge stock is analyzed to illustrate the proposed methodology and to reveal the cost-effectiveness of preventive maintenance interventions.