Effect of Pile Pitch Variation on the Uplift Capacity Using UTM Apparatus

Document Type : Research Article


1 Faculty of Civil Engineering, Shahid Rajaee Teacher Training University, Tehran, Iran

2 Assistant Professr, Faculty of Civil Eng., Shahid Rajaee Teacher Training University, Tehran, Iran.


Using helical piles to reinforce the soil is of little cost and time. The purpose of this paper is to investigate the effects of utilizing helical piles on performance improvement in the uplift capacity and displacement. For this purpose, laboratory specimens of simple and helical piles with the pitch of 13, 20, and 25 mm were investigated. Shahriar sand was used with a relative density of 70% and the compression operation has been performed using hammering. The universal Zwick/Roell Z150 apparatus was employed for tensile. The physical modeling of the helical pile was carried out using dimensional analysis and non-dimensionalization by the Buckingham π  theorem. The results showed that the maximum uplift capacity of helical piles with the pitch of 13, 20, and 25 mm in comparison with the simple pile increased 453.57%, 518.66%, and 436.24%, respectively. When the ratio of the pitch/central shaft diameter is between 1 and 1.5, the tensile capacity was improved by the generated friction and the weight of sand on the blade as a resisting factor. By increasing the ratio of pile pitch to pile diameter to 1.92, the blade torsional angle increased and the sand weight on the blades decreased. Therefore, the uplift capacity was reduced compared to the previous two. The outputs showed that the displacements of the helical piles with different pitch-to-diameter ratios are approximately equal.


Main Subjects

[1] F. Supportworks, Helical Piles and Anchors, Hydraulically Driven Push Piers, Polyurethane Injection, Supplemental Support Systems, 2nd ed., FSI, 2014.
[2] A. Sprince, L. Pakrastinsh, Helical Pile Behaviour and Load Transfer Mechanism in Different Soils, in: Modern Building Materials, Structures and Techniques. Proceedings of the International Conference, Vilnius Gediminas Technical University, Department of Construction Economics …, 2010, pp. 1174.
[3] M. Sakr, F. Bartlett, High capacity helical piles–a new dimension for bridge foundations, in:  Proceedings of 8th international conference on short and medium span bridges, Niagara Falls, Canada, 2010.
[4] R. Merifield, Ultimate uplift capacity of multiplate helical type anchors in clay, Journal of Geotechnical and Geoenvironmental Engineering, 137(7) (2010) 704-716.
[5] S. Ghafarpour Jahromi, P. Nouhi Hefzabad, An Overview of Quasi-Dynamic Method in the Deformation and Seismic Displacement Estimation of retaining Walls, in:  National Conference on Civil Engineering, Architecture and Urban Development of the Islamic World Countries, Tabriz University - Azarbaijan Shahid Madani University- Tabriz University of Applied Sciences and technology, 2018, pp. 1-10.
[6] A. Ebrahimi, H. Rahimzadeh, P. Nouhi Hefzabad, Finite Element modeling for calculating soil slope stability coefficient, in:  National Conference on the Application of new Technologies in Engineering Science, Electrical, Computer and IT, Eivanaki university, 2018, pp. 1-10.
[7] D.J.Y. Zhang, Predicting capacity of helical screw piles in Alberta soils, (1999).
[8] A. Eslami, Foundation engineering, design and implementation, 3rd ed., 2009.
[9] J. Khazaei, A. Eslami, A. Karimi, M. Zarabi, Study of Bearing Capacity of the helical piles using FCV-AUT, in:  The first National Conference on Soil Mechanics and geotechnics, Shahid Rajaee Teacher Training University, Tehran, 2014.
[10] K. Ilamparuthi, P. Ravichandran, M.M. Toufeeq, Study on uplift behaviour of plate anchor in geogrid reinforced sand bed, in:  Geotechnical Earthquake Engineering and Soil Dynamics IV, 2008, pp. 1-10.
[11] S.N. Rao, Y. Prasad, M.D. Shetty, The behaviour of model screw piles in cohesive soils, Soils and Foundations, 31(2) (1991) 35-50.
[12] J.S. Mooney, S. Adamczak, S.P. Clemence, UPLIFT CAPACITY OF HELICAL ANCHORS IN CLAY AND SILT, in:  Unknown Host Publication Title, American Society of Civil Engineers (ASCE), 1985, pp. 48-72.
[13] M. Hasan, N. Samadhiya, Soft soils improvement by granular piles reinforced with horizontal geogrid strips, International Journal of Geotechnical Engineering, 12(1) (2018) 101-108.
[14] Y. Chen, A. Deng, A. Wang, H. Sun, Performance of screw–shaft pile in sand: Model test and DEM simulation, Computers and Geotechnics, 104 (2018) 118-130.
[15] Z.Z. Mosquera, C.d.H. Tsuha, A.T. Beck, Serviceability performance evaluation of helical piles under uplift loading, Journal of Performance of Constructed Facilities, 30(4) (2015) 04015070.
[16] C. Davidson, M. Brown, A. Brennan, J. Knappett, B. Cerfontaine, Y. Sharif, Physical modelling of screw piles for offshore wind energy foundations, in:  1st International Symposium on Screw Piles for Energy Applications, 2019.
[17] A.C.D.-o. Soil, Rock, Standard Practice for Classification of Soils for Engineering Purposes (Unified Soil Classification System) 1, ASTM international, 2017.
[18] B. Rezaei, Investigation of effective parameters on the uplift capacity in the laboratory scale helical piles, Bu- Ali- Sina University, 2013.
[19] D. ASTM, Standard test methods for one-dimensional swell or collapse of soils, in, 2014.
[20] D.-. ASTM, Standard test method for direct shear test of soils under consolidated drained conditions, D3080/D3080M, (2011).
[21] D. ASTM, Standard test methods for minimum index density and unit weight of soils and calculation of relative density, in, West Conshohocken PA., 2006.
[22] A.C.D.-o. Soil, Rock, Standard test methods for maximum index density and unit weight of soils using a vibratory table, ASTM International, 2006.
[23] A.D. -98, Standard test method for laboratory determination of water (moisture) content of soil and rock by mass, in, ASTM International West Conshohocken, PA, 1998.
[24] S.A. Stanier, J.A. Black, C.C. Hird, Modelling helical screw piles in clay and design implications, Proceedings of ICE-Geotechnical Engineering, 167(5) (2013) 447-460.
[25] F.J. Blatt, R. LaBrecque, Principles of physics, in, AAPT, 1988.
[26] K. Fleming, A. Weltman, M. Randolph, K. Elson, Piling engineering, CRC press, 2008.
[27] R. Resnick, J. Walker, D. Halliday, Fundamentals of physics, John Wiley, 1988.
[28] I.H. Shames, I.H. Shames, Mechanics of fluids, McGraw-Hill New York, 1982.
[29] F.M. White, Fluid mechanics, 1999, Google Scholar, (1979) 367-375.
[30] N.P. Kurian, S.J. Shah, Studies on the behaviour of screw piles by the finite element method, Canadian Geotechnical Journal, 46(6) (2009) 627-638.