A Comparison of Fatigue Life Improvement Methods for an Existing Offshore Jacket Platform Structure

  • Authors

    • Swethima Reghu
    • Sruthy S
    2018-09-22
    https://doi.org/10.14419/ijet.v7i4.5.20102
  • ANSYS, Fatigue, hot spot stress, Jacket platform, stress concentration factor

  • Most offshore Jacket platforms are installed in shallow water, less than 300 meters for drilling and production of oil or gas. They are normally fixed to seabed and constructed as three dimensional frameworks with tubular members as structural elements. The surrounding environment around offshore platform is affected by various environmental loads that comprise of wind, waves, currents and earthquake. The major load in such structures is wave loading, repetitive in nature which causes time varying stresses that results global and or local fatigue damage on the offshore steel structure. This study includes fatigue assessment of a selected jacket structure using ANSYS software. This study concentrates mainly on the stress reduction at joints by various methods under the applied cyclic loading. The various methods considered in this study are providing: joint cans with branch stubs, grouted connections, FRP wrappings, stiffeners at the joint section. A comparison of various methods for reducing the hotspot stresses which increases fatigue life are studied and the most effective one is recommended.

     

     

  • References

    1. [1] CHAKRABARTI, SUBRATA K. 2005. HANDBOOK OF OFFSHORE ENGINEERING .Illinois, USA : Elsevier, 2005.

      [2] R G Harwood , E P Shuttleworth “Grouted and mechanical strengthening and repair of tubular steel offshore structureâ€,1988 Techword Services publishing, London.

      [3] A.A. Khalifa, S.Y. AboulHaggag and M.N. Fayed.Fatigue Assessment Analysis of Offshore Structures with Application to an Existing Platform in Suez Gulf, Egypt, World Applied Sciences Journal 30 (8): 1000-1019, 2014

      [4] Almar-Næss, A., (1985), Fatigue Handbook - Offshore Steel Structures

      [5] Seyyed Mahmood Ghassemi Zadeh, Reza Shojayee Baghdar,Seyyed Mohammad Saleh Vaziri Kang Olia. Finite Element Numerical Method for Nonlinear Interaction Response Analysis of Offshore Jacket Affected by Environment Marine Forces Machining Science and Technology, Journal of Marine Science, 2015, 5, 422-442.

      [6] M Aswindas, S.V Venugopal., I. Yamini Sreevalli, A parametric study on efficiency of tubular joint cans in offshore structures, International Journal of Mechanical And Production Engineering, ISSN: 2320-2092

      [7] Baker Jardine.“Fatigue life enhancement of tubular joints by grout injection.â€Health and Safety Executive - Offshore Technology Report

      [8] T S Thandavamoorthy1,A R Santhakumar A G Madhava Rao “Repairing Of Tubular Joints Damaged Under Cyclic Loadings: An Innovative Techniqueâ€,12th WCEE 30 Jan-4th Sept 2000 Auckland, New Zealand.

      [9] DNV RP-C203, DNV Recommended Practice, Fatigue Design of Offshore Steel Structures. Høvik, Norge: DetNorskVeritas, October 2012.

      [10] FUGRO Global Environmental and Ocean Sciences, Gulf of Suez Met Ocean Criteria, July 2009.

      [11] API RP 2A-WSD, API Recommended Practice for planning, designing and constructing fixed offshore platforms - working stress design. Washington: American Petroleum Institute, 2000

      [12] Morison J R., O’ Brien, M P,Johnson, J w.,Schaaf, S.A. The Force Exerted by surface waves on piles. Petroleum Transaction. Vol.(189),1950, 149-157.

      [13] S.E. Abdel Raheem, Elsayed M. A. Abdel Aal., “Nonlinear Analysis of Offshore Structures under Wave Loadingsâ€,15th WCEE 24-28th SEPT 2012 Lisbon – Portugal Vol 1, 1-64, 2009.

      [14] ABS, Guide for the Fatigue Assessment of Offshore Structure, American Bureau of Shipping, ABS Plaza,16855 Northchase Drive, Houston, TX 77060 USA, 2010.

      [15] Kuang, J.G., A.B. Potvin, R.D. Leick and J.L. Kellick, 1977. Stress Concentration in Tubular Joints. Society of Petroleum Engineers Journal.

      [16] R G Harwood , E P Shuttleworth “Grouted and mechanical strengthening and repair of tubular steel offshore structureâ€,1988 Techword Services publishing, London.

      [17] Lesani M. , Bahaari M.R. , Shokrieh M.M.,†FRP wrapping for the rehabilitation of Circular Hollow Section (CHS) tubular steel connectionsâ€, Thin-Walled Structures 90 (2015) 216–234.

      [18] Samindi M.K. Samarakoon, R.M. Chandima Ratnayake. “Strengthening, modification and repair techniques prioritization for structural integrity control of ageing offshore structuresâ€. Reliability Engineering and System Safety 135 (2015)15–26.

      [19] Gandhi, P., G., Raghava and D.S. Ramachandra Murthy, 2000. ‘Fatigue Design of Offshore ring-stiffened welded steel tubular joints’. Journal of Structural Engineering, 126(7): 809-815.

      [20] Graff, W.J., 1981. Introduction to Offshore Structures, Huston, Gulf Publishing.

  • Downloads

  • How to Cite

    Reghu, S., & S, S. (2018). A Comparison of Fatigue Life Improvement Methods for an Existing Offshore Jacket Platform Structure. International Journal of Engineering & Technology, 7(4.5), 333-340. https://doi.org/10.14419/ijet.v7i4.5.20102