Evaluation of Axial Performance of Hollow Bar Micropiles Constructed with Different Drill Bit to Hollow Bar Diameter Ratio

Abstract

Hollow bar micropiles (HBMP) have been popular for some time due to their fast installation and efficient load transfer mechanism. In the construction of HBMP, it is common practice to use a diameter ratio of drill bit/ hollow bar (Db/Dh) between 2 and 2.5. However, increasing the drill bit diameter should increase the micropile diameter and hence may enhance its performance and increase its capacity for a minimal increase in cost. In this study, a field testing program was conducted on six single HBMP with two different (Db/Dh) ratios installed in sand to investigate their performance. The ratio Db/Dh was increased from 2.25 to 3 by increasing the drill bit diameter for the same size hollow bar. The micropile length was 6 m, with 0.25 m free standing above ground. The micropiles were subjected to compression and tension load tests. The results demonstrated that increasing Db/Dh to 3 improved the micropiles performance and increased their compression and uplift capacities: the stiffness increased by 38% and 32% in compression and uplift, while the capacity increased by 17% and 22.5%, respectively. The compressive load–displacement response of micropiles was slightly stiffer than the uplift response and their ultimate compressive capacity was slightly higher than their uplift capacity.

This is a preview of subscription content, access via your institution.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10
Fig. 11
Fig. 12
Fig. 13
Fig. 14
Fig. 15
Fig. 16

References

  1. . AASHTO (2012) AASHTO LRFD bridge design specification, Customary U.S. Units. The American Association of State Highway and Transportation Officials (AASHTO). Section 10

  2. Abd Elaziz AY, El Naggar MH (2012) Axial behaviour of hollow bar micropiles under monotonic and cyclic loading. Geotech Test J 35(2):249–260

    Google Scholar 

  3. Abd Elaziz AY, El Naggar MH (2014) Geotechnical capacity of hollow-bar micropiles in cohesive soils. Can Geotech J 51(10):1123–1138

    Article  Google Scholar 

  4. American Petroleum Institute (API) (1987) Recommended practice for planning, designing and constructing fixed offshore platforms. API Recommended practice 2A, 17 Ed

  5. American Petroleum Institute (API) (2009) Recommended practice for field testing water-based drilling fluids. API Recommended practice RP 13B-1

  6. ASTM International (2013) Standard test methods for deep foundations under static axial compressive load. D1143/D1143M-07 (Reapproved (2013M) American Society for Testing and Materials. West Conshohocken, PA

  7. ASTM International (2015) Standard test methods for deep foundations under static axial compressive load. C900-15. American Society for Testing and Materials, West Conshohocken, PA

  8. ASTM International (2013) Standard test methods for deep foundations under static axial tensile load. D3689/3689M-07 (Reapproved 2013). American Society for Testing and Materials, West Conshohocken, PA

  9. Bruce DA, Nicholson PJ (1989) The practice and application of pin piling. In: Proceedings of the ASCE foundation engineering, Evanston, IL, p 19

  10. Bruce DA, Dimillio AF, Juran I (1997) Micropiles: The state of practice. Part1. Characteristics, definitions and classifications. In: Conference on ground improvement, pp 25–35

  11. Butler HD, Hoy HE (1977) User manual for the Texas quick-load method for foundation load testing. Federal Highway Administration Office of Development, Washington, DC

    Google Scholar 

  12. Davisson MT (1972) High capacity piles. In: Proceedings of soil mechanics lecture series on innovations in foundation construction, American Society of Civil Engineers, Illinois Section, Chicago, pp 81–112

  13. Drbe OE, El Naggar MH (2014) Axial monotonic and cyclic compression behaviour of hollow bar micropiles. Can Geotech J 52:426–441

    Article  Google Scholar 

  14. FHWA (2005) Micropiles design and construction. Federal Highway Administration (FHWA), U.S. Department of Transportation, Washington, D.C. Publication No. FHWA-NHI-05-039

  15. FHWA (2013) Post-tensioning tendon installation and grouting manual. Federal Highway Administration (FHWA), U.S. Department of Transportation, Washington, D.C. Publication No. FHWA-NHI-13-026

  16. Fuller FM, Hoy HE (1970) Pile load tests including quick-load test method conventional methods and interpretations. Highw Res Board HRB 333:78–86

    Google Scholar 

  17. Gomez JE, Rodriguez CJ, Robinson HD, Mikitka J, Keough L (2008) Bond strength of hollow-core bar micropiles. In: Proceedings of 6th annual conference on case histories in geotechnical engineering, Arlington, VA

  18. Han J, Ye SL (2006) A field study on the behavior of micropiles in clay under compression or tension. Can Geotech J 43(1):19–29

    Article  Google Scholar 

  19. Kershaw AK, Luna R (2014) Full-Scale field testing of micropiles in stiff clay subjected to combined axial and lateral loads. J Geotech GeoEnviron Eng 140(1):255–261

    Article  Google Scholar 

  20. Kulhawy FH, Mayne PW (1990). Manual on estimating soil properties for foundation design. Research project No. 1493-6, EL-6800, Electric Power Research Institute, Palo Alto, CA

  21. Kulhawy FH, Hirany A (2009) Interpreted failure load for drilled shafts via Davisson and L1-L2. Selected Papers of the 2009 international foundation congress and equipment expo. ASCE, New York, pp 127–134

  22. Lancellotta R (1995) Geotechnical engineering. A. A. Balkema, Robtterdam

  23. Li J, Kast G (2007) 30 years of GEWI-Pile applications in Canada. Proc. International Society of Micropiles, Toronto

  24. Littlejohn GS, Bruce DA (1977). Rock anchors state-of-the-art. Foundation Publications Ltd., Brentwood, Essex, England, p 50

  25. Pearlman SL Wolosick JR (1992) Pin Piles for bridge foundations. In: Proceedings of 8th annual international bridge conference, Pitsburgh, Pennsylvania, p 8

  26. Reese LC, O’Neill MW (1988). Drilled shafts: construction procedures and design methods. Federal Highway Administration, McLean, Va. FHWA-HI-88-042

  27. Robertson PK (1990) Soil classification using cone penetration test. Can Geotech J 27(1):151–158

    Article  Google Scholar 

  28. Said I (2006) Comportement des interfaces et modelisation des pieux sous charge axiale. PhD thesis, Ecole Nationale des Ponts et Chaussees

  29. Stuedlein AW, Gibson MD, Horvits GE (2008). Tension and compression micropile load test in gravelly sand. In: Conference on 6th international conference on case histories in geotechnical engineering, Arlington, VA

  30. Timothy MJ, Bean JJ, Bolton MK (2012) miniJET: a new type of micropile. In: Proceedings of grouting and deep mixing. American Society of Civil Engineers (ASCE), New Orleans, Louisiana, pp 1095–1104

  31. Wolosick J (2009) Ultimate micropile bond stresses observed during load testing in clays and sands. In: Proceedings, selected papers of the 2009 international foundation congress and equipment expo. ASCE, New York, 12-22selected papers of the, 2009

Download references

Acknowledgements

The authors would like to acknowledge the support of HC MATCON for providing the materials, installing the micropiles and setting the reaction frames, and NSERC for partially funding the project. The authors would also like to thank the Libyan Ministry of Education for providing a scholarship for the first author. The authors would like to acknowledge the effort of Dr. Wenbing Wu from China University of Geosciences for his help during the testing program.

Author information

Affiliations

Authors

Corresponding author

Correspondence to Maged A. Abdlrahem.

Additional information

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Abdlrahem, M.A., El Naggar, M.H. Evaluation of Axial Performance of Hollow Bar Micropiles Constructed with Different Drill Bit to Hollow Bar Diameter Ratio. Geotech Geol Eng (2021). https://doi.org/10.1007/s10706-021-01718-x

Download citation

Keywords

  • Hollow bar micropiles
  • Field load tests
  • Axial capacity
  • Uplift capacity
  • Micropile stiffness