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Field study of group effects on the pullout capacity of “deep” helical piles in sand

Journal Article · · Canadian Geotechnical Journal
 [1];  [1];  [2]
  1. Department of Civil and Environmental Engineering, University of Rhode Island, 2 East Alumni Avenue, Kingston, RI 02881, USA.
  2. Triton Systems, Inc., 330 Billerica Road, Suite 200, Chelmsford, MA 01824, USA.
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This paper presents the results of a field load test program used to investigate group effects on the pullout capacity of single-helix “deep” helical piles/anchors in sand. The high tensile capacity and silent installation of helical piles has given them serious consideration as an alternative to conventional deep foundations and anchors for offshore renewable energy structures. New offshore applications may consider the use of groups of helical piles to resist structural loads. Group interaction effects are known to occur in helical piles, but there is a scarcity of field data on groups in sands under tensile loading. This study involved the installation and load testing of single-helix 152mm diameter round shaft piles and pile groups embedded in sand to depths of 12 and 18 helix diameters below the ground surface. The study was designed to explore the effects of close pile spacing, group configuration (i.e., number of piles), and soil strength (i.e., friction angle) as interpreted from cone penetration test (CPT) resistance. The results showed group efficiencies ranging from about 0.6 to 1.0 at a horizontal spacing of 2 to 3 times the helix diameter in sands with friction angles of about 39° to 44°. The data from this study may also be useful for validation of numerical models for analysis of helical pile group interactions.

Research Organization:
Triton Systems, Inc., Chelmsford, MA (United States)
Sponsoring Organization:
USDOE Office of Science (SC)
DOE Contract Number:
SC0017969
OSTI ID:
1980781
Journal Information:
Canadian Geotechnical Journal, Vol. 59, Issue 4; ISSN 0008-3674
Publisher:
Canadian Science Publishing
Country of Publication:
United States
Language:
English

References (20)

Measurement of Lateral Stress Around Multihelix Anchors in Sand journal January 1984
Scaling Considerations for 1-g Model Horizontal Plate Anchor Tests in Sand journal August 2016
Model investigation of the performance of single anchors and groups of anchors journal April 1994
Numerical study of single helical piles and helical pile groups under compressive loading in cohesive and cohesionless soils journal March 2021
Behaviour of Group of Helical Screw Anchors Under Compressive Loads journal January 2015
Effect of soil deformability on the failure mechanism of shallow plate or screw anchors in sand journal May 2019
Control of screw pile installation to optimise performance for offshore energy applications journal March 2023
Influence of Dilation Angle on Drained Shallow Circular Anchor Uplift Capacity journal February 2017
Historical Development of Iron Screw-Pile Foundations: 1836–1900 journal January 2011
Effects of screw pile installation on installation requirements and in-service performance using the discrete element method journal September 2021
Physical modeling in sand journal June 1994
Experimental and theoretical studies on installation torque of screw anchors journal June 1991
The effect of shape on the pull-out capacity of shallow plate anchors in sand journal April 2019
Helical piles: an innovative foundation design option for offshore wind turbines
  • Byrne, B. W.; Houlsby, G. T.
  • Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, Vol. 373, Issue 2035 https://doi.org/10.1098/rsta.2014.0081
journal February 2015
Stresses and Strains Around Helical Screw Anchors in Sand journal December 1992
Vertical Uplift Capacity of a Group of Helical Screw Anchors in Sand journal March 2013
A Simple Method for Assessing the Peak Friction Angle of Sand at Very Low Confining Pressures journal April 2018
Experimental investigation of the uplift behaviour of circular plate anchors embedded in sand journal June 2002
A review on the behavior of helical piles as a potential offshore foundation system journal February 2020
Pullout Resistance of Buried Anchor in Sand journal September 1988

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