Classification criterion of narrow/wide ice-resistant conical structures based on direct measurements

Abstract

Ice-induced structural vibration generally decreases with an increase in structural width at the waterline. Definitions of wide/narrow ice-resistant conical structures, according to ice-induced vibration, are directly related to structure width, sea ice parameters, and clearing modes of broken ice. This paper proposes three clearing modes for broken ice against conical structures: complete clearing, temporary ice pile up, and ice pile up. In this paper, sea ice clearing modes and the formation requirements of dynamic ice force are analyzed to explore criteria determining wide/narrow ice-resistant conical structures. According to the direct measurement data of typical prototype structures, primary quantitative criterion of the ratio of a cone width at waterline (D) to sea ice thickness (h) is proposed. If the ratio is less than 30 (narrow conical structure), broken ice is completely cleared and a dynamic ice force is produced; however, if the ratio is larger than 50 (wide conical structure), the front stacking of broken ice or dynamic ice force will not occur.

Keywords

narrow/wide structure / broken ice clearing mode / complete clearing / complete unloading / dynamic ice force

References

[1] Brown TG. Four years of ice force observations on the Confederation Bridge. Proceedings of 14th International Conference on Port and Ocean Engineering under Arctic Conditions, 2001, 285-299

[2] Brown TG, Määttänen M. Comparison of Kemi-I and Confederation Bridge cone ice load measurement results. Cold Regions Science and Technology, 2009, 55(1): 3-13

[3] Dalian University of Technology Report on sea ice management, 2005, Dalian: Dalian University of Technology, 2004-2005

[4] Dempsey JP, Fox C, Palmer AC. Ice-slope interaction: transitions in failure mode. Proceedings of Offshore Mechanics and Arctic Engineering Conference, 1999, 225-230

[5] Frederking R. Dynamic Ice force on an inclined structure. Proceedings of IUTAM Symposium on the Physics and Mechanics of Ice, 1980, 104-116

[6] Frederking R, Timco G. Quantitative analysis of ice sheet failure against an inclined plane. Journal of Energy Resources Technology, 1985, 107(3): 160-169

[7] Izumiyama K, Kitagawa H, Koyama K, Uto S. A numerical simulation of ice-cone interaction. Proceedings of IAHR Ice Symposium, 1992, 188-199

[8] Lau M, Molgaarad J, Williams FM, Asj S. An analysis of ice breaking pattern and ice piece size around sloping structures. Proceedings of 18th International Conference on Offshore Mechanics and Arctic Engineering, 1999, 199-207

[9] Liferov P, Bonnemaire B. Ice rubble behavior and strength: Part I. Review of testing and interpretation of results. Cold Regions Science and Technology, 2005, 41(2): 135-151

[10] Määttänen M. The effect of ice pile-up on the ice force of a conical structure. Proceedings of 16th IAHR Ice Symposium, 1990, 1010-1021

[11] Määttänen M, Hoikkanen AN, Avis J. Ice failure and ice loads on a conical structure KEMI-I cone full scale ice force measurement data analysis. Proceedings of 19th IAHR Ice Symposium, 1996, 8-16

[12] Määttänen M, Reddy D, Arockiasamy M, Cheema PS. Ice-structure interaction studied on a lighthouse in the Gulf of Bothnia using response spectrum and power spectral density function analyses. Proceedings of 4th International Conference on Port and Ocean Engineering under Arctic Conditions, 1977, 321-334

[13] Mayne DC, Brown TG. Comparison of flexural failure ice-force models. Proceedings of 19th International Conference on Offshore Mechanics and Arctic Engineering, 2000, 1269-1276

[14] Mayne DC, Brown TG. Rubble pile observations. Proceedings of 10th International Offshore and Polar Engineering Conference, 2000, 596-599

[15] Nevel DE. Ice forces on cones from floes. Proceedings of 11th IAHR Ice symposium, 1992, 1391-1404

[16] Paavilainen J, Tuhkuri J. Parameter effects on simulated ice rubbling forces on a wide sloping structure. Cold Regions Science and Technology, 2012, 81(5): 1-10

[17] Paavilainen J, Tuhkuri J. Pressure distributions and force chains during simulated ice rubbling against sloped structures. Cold Regions Science and Technology, 2013, 85(1): 157-174

[18] Paavilainen J, Tuhkuri J, Polojärvi A. 2D numerical simulations of ice rubble formation process against an inclined structure. Cold Regions Science and Technology, 2011, 68(1-2): 20-34

[19] Qu Y, Yue QJ, Bi XJ, Karna T. A random ice force model for narrow conical structures. Cold Regions Science and Technology, 2006, 45(3): 148-157

[20] Shkhinek K, Uvarova E. Dynamics of the ice sheet interaction with the sloping structure. Proceedings 16th International Conference on Port and Ocean Engineering under Arctic Conditions, 2001, 639-648

[21] Timco G, 1984. Model tests of ice forces on a wide inclined structure. Proceedings of IAHR Ice Symposium, Hamburg, 87–96.

[22] Timco G, Johnston M. Ice loads on the caisson structures in the Canadian Beaufort Sea. Cold Regions Science and Technology, 2004, 38(2-3): 185-209

[23] Wang LY, Xu JZ. Calculation of ice force acting upon a wide cone structure. Engineering Mechanics, 1993, 10(3): 71-80

[24] Xu N. Research on ice force of conical offshore structures, 2011, Dalian: Dalian University of Technology, 93-95

[25] Xu N, Yue QJ. The developing process and risk analysis of ice jams based on field test. Proceedings of the 20th International Conference on Port and Ocean Engineering Under Arctic Conditions, 2009

[26] Xu N, Yue QJ. Dynamic ice forces analysis of conical structure based on direct measurement. Proceedings of the 29th International Conference on Ocean, Offshore and Arctic Engineering, 2010, 771-776

[27] Yue QJ, Bi XJ. Full-scale test and analysis of dynamic interaction between ice sheet and conical structure. Proceedings of 14th International Association for Hydraulic Research (IAHR) Symposium on Ice, 1998, 939-945