MAINTAINING RELIABILITY OF CONCRETE STRUCTURES .2. OPTIMUM INSPECTIONREPAIR

This is the second of two papers that describe the role of in-service inspection/repair in maintaining the reliability of concrete structure s taking into account the randomness of existing damage and damage det ection. Since inspection and maintenance are costly, there are trade-o ffs between the extent and accuracy of inspection, required level of r eliability, and cost. The method to evaluate degradation in strength o f a component described in part 1 is combined with the time-dependent reliability analysis to devise optimum strategies for inspection and m aintenance that minimize the expected future cost of structures and co mponents, while maintaining then limit-state probabilities at or below an established target failure probability. Optimum inspection/repair strategies are sensitive to the relative costs of inspection, repair, and failure as well as to the threshold value of damage detection. Ins pection at approximately uniform intervals leads to near minimum costs for a wide variety of cases studied.