A UNIFIED PROBABILISTIC APPROACH TO DESIGN AND INSPECTION OF OFFSHORE STEEL STRUCTURES

A probabilistic strategy has been developed for determining the relative effectiveness of differing underwater inspection and maintenance regimes (type of inspection, inspection intervals and the policy for responding to defects when found). The strategy requires knowledge of inspection records, fatigue test data and jacket analysis results, including redundancy studies. These data are combined using Bayesian statistics, risk analysis methods and a Monte Carlo simulation technique. The strategy can, and has been, used to developed an inspection planning and management system for offshore structures and can also be used to inform the design process by making it possible to objectively decide on a target design fatigue life to minimize total life costs at minimum risk.