Abstract
The safety of offshore floating units highly depends on the platform’s station keeping capability, which is provided by its mooring system. Mooring chain fatigue failures have recently aroused the interest of the technical community in developing new design and monitoring methodologies focused on considering the effects of corrosion degradation in time. The fatigue limit state and the corrosion allowance of mooring chains are safety requirements that need to be verified continuously through mandatory regular inspections. The present work proposes a new efficient reliability-based method for planning future inspections of mooring chains, which combines recently developed fatigue assessment and corrosion methodologies and takes into account the observations of the previous inspections. The risk-based assessment of the mooring system is continuously updated with new inspection data, being a suitable tool for monitoring the current reliability level of the structure. The method is incorporated into a computational tool that monitors the system reliability and drafts future inspection dates based on a sound safety criterion. Additionally, this work presents a case study as an application of the proposed inspection planning method. The results show that the proposed method is able to optimize the number of inspections in all the analyzed scenarios, and it may be used as a relevant tool to help designers and operators in avoiding mooring chain failures.
