Cost-Benefit Analysis for Offshore Structures Under Structural Deterioration

Abstract The partial or complete interruption of offshore facilities has a direct impact on the political, social, and economic sectors as well as on the environment. Then, these kinds of structures are considered as important systems. Periodic inspection and maintenance activities contribute to maintaining the structural system at satisfactory reliability levels. Based on the above, an approach to determine the optimal inspection interval that represents the minimum total cost using cost-benefit analysis (CBA) is proposed. The total cost involves inspection, repair, and failure cost. The size of crack due to fatigue in critical joints is considered as a damage condition. Demand exceedance rates are used to estimate demands that are involved in the cost of failure. The approach is exemplified on two structures located in different geographical areas of the Bay of Campeche, Mexico. The optimal time for maintenance is five and six years after installing the offshore platform located in Ku and Och area, respectively. The implementation of maintenance actions every five and six years reduces costs by 58% and 61% compared to the absence of maintenance. The proposed approach provides decision-makers with a strategic instrument to optimize the allocation of economic resources for maintenance.