OPTIMAL PLAN FOR INSPECTION AND MAINTENANCE OF STRUCTURAL COMPONENTS BY CORROSION

This paper studies the optimal plan for inspection and maintenance of steel structural components in tension by uniform corrosion, considering the following: A deteriorating model uncertain in time is considered, the probability to detect damage during the inspections is modeled, if damage is detected, the structural component is repaired, the failure probability of the component over time is considered supposing that the demands and capacities are random in time, the optimal plan will be the one in which the expected costs (costs of inspection, repair and failure) are minimum in the life cycle of the component, allowing to detect the number of inspections that minimize the expected costs; to determine the optimal plan, all the possibilities that are given of the tree diagram are studied, where each inspection has two existent possibilities: repair or not to repair, the occurrence possibility of each branch in the resulting tree diagram is calculated. In addition, the influence of the variables and parameters are calculated as: the net discount rate of money (r), uniform corrosion rate (v), the mean load (mu(S)), failure costs (C-f), repair cost (C-rep) inspection cost (C-ins) and quality of a nondestructive inspection (eta(0.5)). The results indicate that the optimal number of inspections in the life-cycle of the component is sensible to each of the parameters involved, therefore every value of the variables that intervene in an optimization study must be fully justified.