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Research Papers: Offshore Technology

Quasi-Static Analysis of the Multicomponent Mooring Line for Deeply Embedded Anchors

[+] Author and Article Information
Zhen Guo

Research Center of Coastal and Urban
Geotechnical Engineering,
College of Civil Engineering and Architecture,
Zhejiang University,
Hangzhou 310058, Zhejiang, China
e-mail: nehzoug@163.com

Lizhong Wang

Professor
Research Center of Coastal and Urban
Geotechnical Engineering,
College of Civil Engineering and Architecture,
Zhejiang University,
Hangzhou 310058, Zhejiang, China
e-mail: wlzzju@163.com

Feng Yuan

Research Center of Coastal and Urban
Geotechnical Engineering,
College of Civil Engineering and Architecture,
Zhejiang University,
Hangzhou 310058, Zhejiang, China
e-mail: yuanfen5742@163.com

1Corresponding author.

Contributed by the Ocean, Offshore, and Arctic Engineering Division of ASME for publication in the JOURNAL OF OFFSHORE MECHANICS AND ARCTIC ENGINEERING. Manuscript received November 6, 2011; final manuscript received November 5, 2015; published online December 10, 2015. Editor: Solomon Yim.

J. Offshore Mech. Arct. Eng 138(1), 011302 (Dec 10, 2015) (9 pages) Paper No: OMAE-11-1097; doi: 10.1115/1.4031986 History: Received November 06, 2011; Revised November 05, 2015

Multicomponent taut mooring lines are widely used to secure floating facilities to anchors embedded in the seabed to restrict motions. Optimal design of the mooring line system requires a realistic model of the combined performance of all segments of the mooring line, including the separate segments contained within both the water column and the soil column. This paper presents a two-dimensional quasi-static model, which can analyze mooring lines comprising multiple types of mooring lines or chains, taking into account the effects of ocean currents, soil resistance, and elastic elongation of mooring line. An example analysis is carried out to predict the responses of multicomponent mooring line during pretension and under service conditions. The example analysis puts special focus on conditions where the floating facility undergoes a series of motion away from its original position to assess the effect of the vertical offset is studied in detail. Finally, based on the presented model, the performances of different components of the mooring system are thoroughly investigated and some useful conclusions are drawn.

Copyright © 2016 by ASME
Topics: Mooring , Chain , Soil
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References

Andersen, K. H. , Murff, J. D. , Randolph, M. F. , Clukey, E. C. , Erbrich, C. T. , Jostad, H. P. , Hansen, B. , Aubeny, C. , and Sharma, P. , 2005, “ Suction Anchors for Deepwater Applications,” International Symposium on Frontiers in Offshore Geotechnics, pp. 3–30.
Murff, J. D. , Randolph, M. F. , Kolk, H. J. , Ruinen, R. M. , Strom, P. J. , and Thorne, C. P. , 2005, “ Vertically Loaded Plate Anchors for Deepwater Applications,” International Symposium on Frontiers in Offshore Geotechnics, pp. 31–48.
Smith, T. M. , Chen, M. C. , and Radwan, A. M. , 1985, “ Systematic Date for the Preliminary Design of Mooring Systems,” 4th International Offshore Mechanics and Arctic Engineering Symposium, Vol. 1, pp. 403–407.
Smith, R. J. , and MacFarlane, C. J. , 2001, “ Statics of a Three Component Mooring Line,” Ocean Eng., 28(7), pp. 899–914. [CrossRef]
Chai, Y. T. , Varyani, K. S. , and Barltrop, N. D. P. , 2002, “ Semi-Analytical Quasi-Static Formulation for Three-Dimensional Partially Grounded Mooring System Problems,” Ocean Eng., 29(6), pp. 627–649. [CrossRef]
Yu, L. , and Tan, J. H. , 2005, “ Research on Optimum Multi-Component Mooring Lines Based on Catenary Equation,” Ocean Eng., 23(1), pp. 69–73 (in Chinese).
Reese, L. C. , 1973, “ A Design Method for an Anchor Pile in a Mooring System,” 5th Annual Offshore Technology Conference, Houston, TX, Apr. 29–May 2, pp. 209–214.
Gault, J. A. , and Cox, W. R. , 1974, “ Method for Predicting Geometry and Load Distribution in an Anchor Chain From a Single Point Mooring Buoy to a Buried Anchorage,” 6th Annual Offshore Technology Conference, Houston, TX, May 6–8, pp. 309–318.
Vivatrat, V. , Valent, P. J. , and Ponterio, A. A. , 1982, “ The Influence of Chain Friction on Anchor Pile Design,” 14th Annual Offshore Technology Conference, Houston, TX, pp. 153–163.
Degenkamp, G. , and Dutta, A. , 1989, “ Soil Resistances to Embedded Anchor Chain in Soft Clay,” ASCE J. Geotech. Eng. Div., 115(10), pp. 1420–1438. [CrossRef]
Neubecker, S. R. , and Randolph, M. F. , 1995, “ Profile and Frictional Capacity of Embedded Anchor Chains,” ASCE J. Geotech. Eng. Div., 121(11), pp. 797–803. [CrossRef]
Neubecker, S. R. , and Randolph, M. F. , 2004, “ Study of Chain Slippage for Embedded Anchors,” 36th Annual Offshore Technology Conference, Houston, TX, May 3–6, pp. 668–676.
Aubeny, C. , and Chi, C. M. , 2014, “ Analytical Model for Vertically Loaded Anchor Performance,” ASCE J. Geotech. Geoenviron. Eng., 140(1), pp. 14–24. [CrossRef]
House, A. R. , 2002, “ Suction Anchor Foundations for Buoyant Offshore Facilities,” Ph.D. thesis, The University of Western Australia, Perth, Australia.
Berteaux, H. O. , 1976, Buoy Engineering, Wiley, New York.
Wilson, B. W. , 1960, “ Characteristics of Anchor Cables in Uniform Ocean Currents,” A & M College of Texas, College Station, TX, Technical Report No. 204-1.
Yen, B. C. , and Tofani, G. D. , 1984, “ Soil Resistance to Stud Link Chain,” 16th Annual Offshore Technology Conference, Houston, TX, Paper No. OTC 4769, pp. 1–10.
API RP 2SK, 2005, Recommended Practice for Design and Analysis of Stationkeeping Systems for Floating Structures, 3rd ed., API Publishing Services, Washington, DC.

Figures

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Fig. 1

Arrangement of a multicomponent mooring line

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Fig. 2

Forces acting on the mooring line: (a) line suspended in water and (b) line embedded in soil

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Fig. 3

Bearing capacity factor

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Fig. 4

Discrete model for multicomponent mooring line

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Fig. 5

Force sketch of discrete segments: (a) segments in water and (b) segments in soil

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Fig. 6

Module one for the mooring line during pretension

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Fig. 7

Module two for the mooring line in service

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Fig. 8

Line profiles at different pretension levels

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Fig. 9

Uplift angles at different pretension levels

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Fig. 10

Profiles of mooring line at given moments

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Fig. 11

Effect of vertical offsets on the line tension

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Fig. 12

Effect of vertical offset on uplift angle

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Fig. 13

Line profiles for different combination moorings

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Fig. 14

Line tensions of top point under the motion

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Fig. 15

Line tensions under the motion

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