Fatigue Data for Reliability‐Based Offshore Platform Inspection and Repair
Publication: Journal of Structural Engineering
Volume 117, Issue 10
Abstract
Fatigue of welded fixed offshore platforms is a primary design and operational concern. Environmental, fatigue data, and method uncertainties, as well as inspection and repair activities, are major parameters that influence the welded joint reliability. This paper investigates and establishes the relation between welded tubular joint fatigue life computed from a deterministic design process and the probability of occurrence of: (1) First detectable crack; (2) first through‐thickness cracking; and (3) total joint failure stages. Several experimental fatigue data bases were used to derive the appropriate probabilistic distributions and relations between different joint failure stages. The effect of repair methods, such as repair welding and grinding, on the fatigue life is studied, and parameters that modify the probability of joint failure states are introduced. The data examined show that time to first discernible surface cracking for welded tubular joints is about 10‐65% of the time to through‐thickness cracking, with a mean value of 35%. The total joint failure will occur at about 150% of the time to through‐thickness crack. Simplified relations between crack size and remaining fatigue life are derived based on recent experimental results. Data presented in this paper provide the basic tools for performing a reliability‐based inspection and repair assessment.
Get full access to this article
View all available purchase options and get full access to this article.
References
1.
Background to new fatigue design guidance for steel welded joints in offshore structures. (1984). U.K. Dept. of Energy, HMSO, London, U.K.
2.
Carr, P., Clayton, M., Busby, P. L., and Dobson, J. (1986). “A probabilistic strategy for subsea inspection of steel structures.” J. Soc. Petroleum Engrs., 187–195.
3.
“Design of tubular joints for offshore structures.” (1985). UR33, Underwater Engineering Group (UEG Publications, London, England.
4.
Hanna, S. Y. (1988). “Fatigue model for reliability based inspection and repair of welded tubular offshore structures.” Conoco Report M‐33‐88.
5.
Karsan, D. I., and Kumar, A. (1990). “Fatigue failure parts for platform inspection.” J. Struct. Engrg., ASCE, 116(5), 1679–1695.
6.
Karsan, D. I., Kumar, A., and Hanna, S. Y. (1988). “Failure path identification for fixed offshore structures subjected to fatigue.” Proc. Int. Conf. on the Behavior of Offshore Structures, BOSS '88, Trondheim, Norway, June, 1223–1238.
7.
Knapp, A. E., and Stahl, B. (1985). “Offshore platform fatigue cracking probability.” Struct. Engrg., ASCE, 111(8), 1647–1660.
8.
Kumar, A., and Karsan, D. I. (1989). “Rational inspection of offshore platforms.” Proc. 8th Offshore Mechanics and Arctic Engineering Conf., (OMAE 89), 1, 293–300.
9.
Martindale, S. G., and Wirsching, P. H. (1983). “Probability‐based progressive fatigue collapse.” J. Struct. Engrg., ASCE, 109, 1792–1811.
10.
“Offshore installation: Guidance on design and construction.” (1984). U.K. Dept. of Energy, HMSO, London, U.K.
11.
Proc. of the Third Int. European Coal and Steel Community (ESC) Offshore Conference on Steel in Marine Structures (SIMS 87) Delft, The Netherlands.
12.
Stahl, B., and Geyer, J. F. (1984). “Fatigue reliability of parallel member systems.” J. Struct. Engrg., ASCE, 110(10), 2307–2323.
13.
Tweed, J. H. (1987). “Surface crack behavior of UKSRP‐joints and implications for predicting remaining fatigue life of defective tubular joints.” Proc. of the Third Int. European Coal and Steel Community (ESC) Offshore Conference on Steel in Marine Structures (SIMS 87), Delft, The Netherlands, 845–858.
14.
Tweed, J. H., and Freeman, J. H. (1987). “Remaining fatigue life of defective tubular joints: An assessment based on surface crack growth in tubular joint fatigue tests.” Offshore Technology Report, OTH 87 259, HMSO, London, U.K.
15.
UKOSRP IT. Summary and task reports. (1987). HMSO, London, U.K.
16.
Wirsching, P. H. (1981). “Fatigue reliability analysis in offshore structures.” Probabilistic methods in structural engineering. M. Shinozaka and T. P. Yao, eds., ASCE, New York, N.Y., 293–307.
17.
Wirsching, P. H. (1984). “Fatigue reliability for offshore structures.” J. Struct. Engrg., ASCE, 110(10), 2340–2356.
Information & Authors
Information
Published In
Copyright
Copyright © 1991 ASCE.
History
Published online: Oct 1, 1991
Published in print: Oct 1991
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.