The present paper first gives a brief outline of the simplified and generic approach to reliability and risk based inspection planning and thereafter sets focus on a recent application of the methodology for planning of in-service NDT inspection of the fixed offshore steel jacket structures in the DUC concession area in the Danish part of the North-Sea. The platforms are operated by Maersk Oil and Gas on behalf of DUC partners A.P.Moller, Shell and Texaco. The study includes a sensitivity analysis performed for the identification of relevant generic parameters such as the bending to membrane stress ratio, the design fatigue life and the material thickness. Based on the results of the sensitivity analysis a significant number of inspection plans were compared for fixed generic parameters (pre-defined generic plans) and a data-base named iPlan was developed from which inspection plans may be obtained by interpolation between the pre-defined generic plans. The iPlan data-base facilitates the straightforward production of large numbers of inspection plans for structural details subject to fatigue deterioration. In the paper the application of the generic inspection plan data-base iPlan is finally illustrated on an example. The implemantation into the Excel spreadsheet iPlan for practical application is shown. Acceptance criteria have been considered for the inspection planning of fatigue sensitive structural details of jacket steel structures. It has been described how the acceptable annual probability of fatigue failure for specific details may be derived on the basis of the RSR for the structure given fatigue faulire of the considered detail. Generic inspection plans can be derived for different structural details (SN curves), FDF values (Fatigue Design Factor), RSR values (Reserve Strength Ratio), inspection, repair and failure costs and inspection/repair methods. It is noted that generic inspection plans may also be applied as a decision tool for evaluating the effect of servive life extensions, load increases and strengthening on the required inspection and maintenance effort.
Field implementation of RBI for jacket structures
Felderprobung der sicherheits- und risikobasierten Inspektionsplanung
2003
10 Seiten, 6 Bilder, 4 Tabellen, 10 Quellen
Conference paper
English
Field implementation of RBI for jacket structures
Tema Archive | 2005
|Probabilistic inspection planning of jacket structures
Tema Archive | 1999
|