ENG  Vol.4 No.12 , December 2012
Design Considerations for Pile Groups Supporting Marine Structures with Respect to Scour
Abstract
Piles supporting marine structures such as jetties, relieving platforms, quay walls and fixed offshore structures are subjected to lateral loads due to berthing and mooring forces, wind, waves, storm surges and current forces. This paper presents some factors that affect the design of pile groups supporting marine structures founded in cohesionless soils. Some main aspects that should be considered in the pile group design are addressed such as pile batter angle, pile group arrangement, pile spacing, pile slenderness ratio and magnitude of lateral static loading. Numerical analyses were conducted to investigate these design aspects with and without impact of scour. Different scour depths were considered to cover the possible root causes of scour around pile groups such as waves, current and ship propeller jets. The study revealed that scour has greater impact on lateral loading of pile groups compared to its impact on single piles. Pile groups with side-by-side arrangement exposed to scour are more critical than single piles and piles groups with tandem arrangement due to the combined effect of scour and pile-soil-pile interaction. It is also concluded that scour protection is not always required. More attention and considerations should be given to scour protection around piles especially if the piles are closely spaced, arranged side-by-side and if slenderness ratio is less than 12.5.

Cite this paper
Y. Mostafa, "Design Considerations for Pile Groups Supporting Marine Structures with Respect to Scour," Engineering, Vol. 4 No. 12, 2012, pp. 833-842. doi: 10.4236/eng.2012.412106.
References

[1]   B. M. Sumer, J. FredsØe and N. Christiansen, “Scour around a Vertical Pile in Waves,” Journal of Waterway, Port, Coastal and Ocean Engineering, ASCE, Vol. 118, No. 1, 1992, pp. 15-31. doi:10.1061/(ASCE)0733-950X(1992)118:1(15)

[2]   B. M. Sumer and J. Freds?e, “Wave Scour around Group of Vertical Piles,” Journal of Waterway, Port, Coastal and Ocean Engineering, ASCE, Vol. 124, No. 5, 1998, pp. 248-255. doi:10.1061/(ASCE)0733-950X(1998)124:5(248)

[3]   Y. E. Mostafa and A. F. Agamy, “Scour around Single Pile and Pile Groups Subjected to Waves and Currents,” International Journal of Engineering Science and Technology, IJEST, Vol. 3, No. 11, 2011, pp. 8160-8178.

[4]   C. Lin, C. Bennett, J. Han and R. L. Parsons, “Integrated Analysis of the Performance of Pile-Supported Bridges under Scoured Conditions,” Engineering Structures, Vol. 36, 2012, pp. 27-38. doi:10.1016/j.engstruct.2011.11.015

[5]   Y. N. Kishore, S. N. Rao and J. S. Mani, “The Behaviour of Laterally Loaded Piles Subjected to Scour in Marine Environment,” KSCE Journal of Civil Engineering, Vol. 13, No. 6, 2009, pp. 403-406. doi:10.1007/s12205-009-0403-2

[6]   C. Lin, C. Bennett, J. Han and R. L. Parsons, “Scour Effects on the Response of Laterally Loaded Piles Considering Stress History of Sand,” Computers and Geotechnics, Vol. 37, No. 7-8, 2010, pp. 1008-1014.

[7]   Y. E. Mostafa, “Effect of Local and Global Scour on Lateral Response of Single Piles in Different Soil Conditions,” Engineering, Vol. 4, No. 6, 2012, pp. 297-306.

[8]   S. Ni, Y. Huang and L. Lo, “Numerical Investigation of the Scouring Effect on the Lateral Response of Piles in Sand,” Journal of Performance of Constructed Facilities, Vol. 263, 2012, pp. 320-325. doi:10.1061/(ASCE)CF.1943-5509.0000224

[9]   Ensoft Inc., “GROUP, A Program for Analyzing a Group of Piles Subjected to Axial and Lateral Loading,” Version 7.0, Technical Manual, Austin, 2006.

[10]   R. Whitehouse, “Scour at Marine Structures, A Manual for Practical Application,” Thomas Telford Publications, London, 1998. doi:10.1680/sams.26551

[11]   M. F. Randolph, “PIGLET. A Program for Analysis and Design of Pile Groups,” Version 5.1, Technical Manual, The University of Western Australia, Perth, 2004.

[12]   L. M. Zhang, M. C. McVay, S. J. Han, P. W. Lai and R. Gardner, “Effects of Dead Loads on the Lateral Response of Battered Pile Groups,” Canadian Geotechnical Journal, Vol. 39, No. 3, 2002, pp. 561-575. doi:10.1139/t02-008

[13]   T. Tazoh1, M. Sato, J. Jang and G. Gazetas, “Centrifuge Tests on Pile Foundation-Structure Systems Affected by Liquefaction-Induced Soil Flow after Quay Wall Failure,” The 14th World Conference on Earthquake Engineering, Beijing, 12-17 October 2008.

[14]   S. S. Rajashree and T. G. Sitharam, “Nonlinear FiniteElement Modeling of Batter Piles under Lateral Load,” Journal of Geotechnical and Geoenvironmental Engineering, Vol. 127, No. 7, 2001, pp. 604-612. doi:10.1061/(ASCE)1090-0241(2001)127:7(604)

[15]   G. P. Tschebotarioof, “The Resistance to Lateral Loading of Single Piles and Pile Groups,” Special Publication No. 154, ASTM, 1953, pp. 38-48

[16]   R. E. Harn, “Displacement Design of Marine Structures on Batter Piles,” 13th World Conference on Earthquake Engineering, Vancouver, 1-6 Augsut 2004, Paper No. 543.

[17]   B. M. Sumer, K. Bundgaard and J. Freds?e, “Global and Local Scour at Pile Groups,” Proceedings of the Fifteenth International Offshore and Polar Engineering Conference, Seoul, 19-24 June 2005, pp. 577-583.

[18]   A. Yuksel, Y. Celikoglu, E. Cevik and Y. Yuksel, “Jet Scour around Vertical Piles and Pile Groups,” Ocean Engineering, Vol. 32, No. 3-4, 2005, pp. 349-362. doi:10.1016/j.oceaneng.2004.08.002

[19]   C. Chin, Y. Chiew, S. Y. Lim and F. H. Lim, “Jet Scour around Vertical Pile,” Journal of Waterway, Port, Coastal and Ocean Engineering, Vol. 122, No. 2, 1996, pp. 59-67. doi:10.1061/(ASCE)0733-950X(1996)122:2(59)

[20]   D. A. Brown, C. Morrison and L. C. Reese, “Lateral Load Behavior of Pile Group in Sand,” Journal of Geotechnical Engineering, ASCE, Vol. 114, No. 11, 1988, pp. 13261343. doi:10.1061/(ASCE)0733-9410(1988)114:11(1261)

[21]   A. Abdeldayem, G. Elsaeed and A. Ghareeb, “Effect of Pile Group Arrangements on Local Scour Using Numerical Models,” Advances in Natural and Applied Sciences, Vol. 52, 2011, pp. 141-146.

 
 
Top