Optimal time intervals for maintenance in jacket platforms based on cost-benefit analysis

The development of effective maintenance strategies for offshore platforms is essential to preserve their reliability at acceptable levels.Thus, the environmental and economic consequences of possible structural failures are prevented.This work presents a methodology to estimate the optimal time interval for maintenance actions based on cost benefit analysis (CBA).Structural reliability is estimated in terms of the expected number of failures while the expected total cost considers the cost of inspection, repair and failure in time.Demand exceedance rates are used to estimate demands in time.The uncertainties related to manufacturing process and wave occurrences are considered.The structural damage is defined as the crack growth at different hot spots of the tubular members due to fatigue.Optimal time intervals are estimated on a jacket offshore platform located in the Gulf of Mexico.The results indicate that the optimal time interval is equal to 5 years for systems in which the cost is reduced by about 61% compared to the absence of maintenance.The methodology provides an outline that helps to make the most appropriate decision to extend the useful life of an offshore system.