Effect of Pile Scouring on the Structural Behavior of a Fixed Jacket Platform with Consideration of Non-linear Pile Seabed Interaction

Document Type: Regular Paper

Authors

1 Faculty Member, Assistant Professor, Marine Engineering Department, Petroleum University of Technology, Mahmoudabad, Iran

2 M.Sc. Student, Marine Engineering Department, Petroleum University of Technology

Abstract

In offshore structures, most of failures are caused by the lack of sufficient piles strength. Scour phenomena affects the load transition and the pile strength. The necessity of the consideration of scouring phenomena amplifies when the scour depth becomes remarkable, which can endanger the jacket stability. In this paper, a new method is used to consider the pile scouring using nonlinear pushover analysis with SACS software. A recently-built existing jacket platform namely SPD 19C is selected as a case study. Results show that Reserve Strength Ratio (RSR) of the jacket platform decreases when scour depth increased in the both aged and recently-built cases. RSR decreasing becomes more sensible as scour depth increases. According to API RP2A collapse will be occurred in the range of RSR< 1.6. It is shown at RSR=1.6, collapse will be occurred in the scouring depth of 13.5m and 11m for recently-built and aged platform respectively, which both have approximately 27% lower RSR than their original state. So scour protection methods should be addressed in vulnerable areas as preventive alternatives.

Keywords

Main Subjects


1] Nichols, N. W., Goh, T. K., and Bahar, H. (2006). “Managing Structural Integrity for Aging Platform,” in SPE Asia Pacific Oil and Gas Conference and Exhibition, Adelaide,Australia, DOI: 10.2118/101000-MS.

[2] Sumer, B. M., and Fredsøe, J., (2002). “The Mechanics of Scour in the Marine Environment.” Denmark: world scientific Publishing Co. Pte. Ltd, vol. 17, ISBN: 981-02-4930-6.

[3] Coastal Engineering Manual (2001). Scour and Scour Protection. Chapter VI—5-6, Engineer Manual EM 1110-2-1100, Headquarters, U.S. Army Corps 01 Engineers, Washington, D. C.

[4] Breusers, H.N.C. and Raudkivi, A.J. (1991).” Scouring.” A.A. Balkema, Rotterdam, viii + 143 p, Bib ID: 1890407, ISBN 10: 9061919835, ISBN 13: 9789061919834.

[5] Melville, B.W. and Coleman, S.E. (2001). “New Zealand Bridge Scour Experiences”. JOURNAL OF HYDRAULIC ENGINEERING, DOI: 10.1061/ (ASCE) 07339429(2001)127:7(535).

[6] Herbich, J.B. (1981). “Scour around pipelines and other objects.” Offshore Pipeline Design Elements. Marcell Dekker Inc., New York, 43-96.

[7] Herbich, J.B., Schiller, R.E., Jr., Watanabe, R.K. and Dunlap, W.A. (1984). “Seafloor Scour.” Design Guidelines for Ocean-Founded Structures, Marcell Dekker Inc., New York, ISBN-10: 0824770951.

[8] Mao, Y. (1986). “The interaction between a pipeline and an erodible bed.” PhD Thesis fulfillment article, Series Paper 39, Tech. Univ. of Denmark, ISVA, DOI: 10.1061/ (ASCE) 0733-950X (1988)114:1(81).

[9] Ettema, R. (1976). “Influence of bed material gradation on local scour”. Report No. 124, University of Auckland, Department of Civil Engineering.

[10] Baker R. A. (1986). “Local Scour at Bridge Piers in Non-Uniform Sediment.” MSc Thesis fulfillment article, University of Auckland, New Zealand, ISSN: 0111-0136.

[11] Melville, B.W. and Sutherland, A.J. (1988). “Design methods for local scour at bridge piers.” Hydraulic Engineering, ASCE, vol. 1114, No. 10, pp 1210-1226, DOI: 10.1061/ (ASCE) 0733-9429(1988)114:10(1210).

[12] Sumer, B.M., Christiansen, N. and Fredsøe, J. (1993). “Influence of cross section on wave scour around piles.” Waterway, Port, Coastal and Ocean Engineering, ASCE, vol. 119, No. 5, pp 477-495, DOI: 10.1061/ (ASCE) 0733-950X (1993)119:5(477).

[13] Briaud J.-L., Ting, F.C.K., Chen, H.C., Gudavalli, R. perugu, S. and Wei, G. (1999). “Prediction of Scour Rate in cohesive Soils at bridge piers.” Geotechnical and Geoenviromental Engineering, ASCE, vol. 125, No. 4, pp 237-246, ISSN: 1090-0241.

[14] Stahlmann, A., (2013). “Numerical and Experimental Modeling of Scour at Foundation Structures for Offshore Wind Turbines “International Offshore and Polar Engineering (ISOPE), Document ID:  ISOPE-I-13-031, ISBN 978-1-880653-99–9 and ISSN 1098-6189.

[15] Fen Li, Jie Han, Cheng Lin (2013). “Effect of Scour on the Behavior of Laterally Loaded Single Piles in Marine Clay”, Marine Georesources & Geotechnology, Volume 31, 2013- Issue 3. DOI: 10.1080/1064119X.2012.676157.

[16] Harris, J., Whitehouse, R., Todd, D., Gunn, L., Lewis, R., (2016). “Analyzing Scour Interaction between Submarine Pipelines, Valve Station and Mechanical Protection Structures”, Offshore Technology Conference, Document ID:  OTC-27289-MS, DOI: 10.4043/27289-MS.

[17] Haitao Zhang, Xianqi Luo, Jinfeng Bi, Hui Shen (2016). “Seabed Scour around Inclined-pile Group Foundation of Offshore Wind Turbine”, International Ocean and Polar Engineering Conference (ISOPE), Document ID:  ISOPE-I-16-213, ISBN: 978-1-880653-88-3, ISSN 1098-6189.

[18] Robert F. Stevens, Kevin Smith, Lawrence Soosainathan, and James Fisher, Mohamed M. Mekkawy, Amir Rahim, Daniel P. O'Connell, (2017). “Seabed Scour Considerations for Marine Renewable Energy Facilities”, Offshore Technology Conference, Document ID: OTC-27863-MS, DOI: 10.4043/27863-MS.

[19]George, J. M., Wahab, M. M. A. and Kurian, V. J., (2016). "Changes in the Pushover Analysis of Offshore Jacket Platforms Due to the Incorporation of the Aging Effect of Piles," ARPN Journal of Engineering and Applied Science, VOL. 11, NO. 4, ISSN 1819-6608.

[20] Narayanan, S. P. and Kabir, M., (2009). “Structural Integrity Management for Fixed Offshore Platform in Malaysia”, World Academy of Science, Engineering and Technology, Malaysia, vol. 3, No. 10. DOI: 1999.3/6666.

[21] API, (2013). Structural Integrity Management of Fixed Offshore Structures, American Petroleum Institute, DOI: 10.4043/20675-MS.

[22] API, (2014). Planning, Designing, and Constructing Fixed Offshore Platforms-WSD, American Petroleum Institute, DOI: 10.4043/23558-MS.


Volume 6, Issue 2 - Serial Number 12
Summer and Autumn 2018
Pages 20-28
  • Receive Date: 03 August 2017
  • Revise Date: 21 August 2017
  • Accept Date: 05 September 2017