This paper has the main purpose to describe the overview development of a Risk Based Inspection (RBI) methodology applicable to a semisubmersible production platform. Considering news and inventive methodologies for: inspection, acquisition and management of corrosion rates, critical points monitoring, crack propagation studies based on fracture mechanics, structural reliability and a structural database in order to facilitate the structural management in the asset. The data for this paper are based on inspection historical data and hydrodynamic and structural analysis software ABS OSAP System; see reference 8, to provide the structural results of buckling and fatigue analysis. RBI methodology can be applied to semisubmersible platforms in order to rationalize the structure integrity management, as well as optimize the class process maintenance.

The RBI methodology when compared with the traditional method has a lot of advantages as: focusing inspection during the unit life, lower accidents risk, resulting in the reduction of the maintenance cost. The main focus of RBI methodology for semi's concentrate in the reduction of underwater scope of inspection, while increase the importance of focusing critical areas based on the risk assessment and reliablility results.

The proposed paper has a significant contribution to the knowledge on reliability of semisubmersible, as well as the optimization and rationalization of integrity management.


The pioneer development of RBI for FPSO has been done during the year of 2001. It has been a result of significant joined efforts from different companies and the first implemented RBI in the world. Since this time, the methodology has been improved and for different purposes ABS also establishes different levels for the methodology and respective requirements. Considering the needs to optimize the conventional survey inspection programs of a semi-submersible Platform, the RBI methodology has been considered a next step of new technology to be invstigated. In order to reach the objective some tasks have been carried out and will be described on this paper.

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