Cost of life extension of deteriorating structures under reliability-based maintenance

Due to intensive investments in the construction of civil infrastructures in the 1960s and 1970s, the number of deteriorating structures has increased considerably in the last decade. In many cases these structures require unavailable financial resources for inspection, maintenance, repair, rehabilitation, and replacement. As a consequence, there is an urgent need for developing cost-effective maintenance strategies for deteriorating structures. The existing structures management models evaluate the need for maintenance using measures of the strength deterioration of the structure. Strength deterioration is not a consistent measure of safety and for this reason, in this paper, the reliability index is used as a measure of structural performance. The time-dependent reliability index and the effect of maintenance actions are described using a model based on that proposed by the second author. In spite of the importance of the cost of a maintenance action and of its effects on the reliability index, there is very limited information on the relation between the cost and the effect of maintenance actions. In this paper, a model considering the interaction between maintenance cost and its effect on the reliability index is proposed. This model is used to compare the cost-effectiveness of several maintenance strategies for a deteriorating structure. The effect of the parameters associated with the cost model on the optimal maintenance scenario is also analyzed.