Skip to main content
SpringerLink
Log in

Experimental and Numerical Investigation of Load Sharing Ratio for Piled Raft Foundation in Granular Soils

  • Geotechnical Engineering
  • Published:
KSCE Journal of Civil Engineering Aims and scope

Abstract

If the rigidity and the bearing capacity of the soil under a superstructure are not efficient to bear loads of structures, a common remedy is to increase the depth of the footing to transmit loads to soil layers having high bearing capacity (well graded dense gravel, gravelly sand, hard clay, rock, etc.) by using the pile group. Piled raft foundation (PRF) has come a significant footing system of late years due to that it combines load-carrying capacities of piles and raft. Therefore, extensive empirical, numeric and analytical studies have been carried out for reliable design of these footing system. Nonetheless, the load sharing ratio (LSR) between the driven piles and the raft received no attention from researchers. It is aimed to examine the LSR between the driven pile group and the raft in this study. Therefore, a testing apparatus was set up, and loading tests were carried out including the raft and the piled raft cases. Thus, the LSR of the piles and the raft were measured by means of the tests, and the effect of the pile length and relative density on this ratio was also investigated. The model of the test setup was determined numerically for same loading conditions and the material properties by using ABAQUS software. From the test and finite element analysis results, it has been found that rafts share foundation loads at such levels that should not be ignored. Vertical settlements of raft foundations at certain loads are found to be greater than the settlements of piled raft foundations at the same loads. Relative density was observed to be effective in the range of 1–2% on the LSR of the piles in PRFs. In addition to this, the length of the pile was found to be more effective on this ratio in the range of 11–14%.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

References

  • ASTM D854 (2006) Standard test methods for specific gravity of soil solids by water pycnometer. ASTM D854, ASTM International, West Conshohocken, PA, USA

    Google Scholar 

  • ASTM D3080M-11 (2011) Standard test method for direct shear test of soils under consolidated drained conditions. ASTM D3080M-11, ASTM International, West Conshohocken, PA, USA

    Google Scholar 

  • ASTM D4253-16 (2016) Standard test methods for maximum index density and unit weight of soils using a vibratory table. ASTM D4253-16, ASTM International, West Conshohocken, PA, USA

    Google Scholar 

  • ASTM D4254-16 (2016) Standard test methods for minimum index density and unit weight of soils using a vibratory table. ASTM D4254-16, ASTM International, West Conshohocken, PA, USA

    Google Scholar 

  • ASTM D6913 (2017) Standard test methods for particle-size distribution (gradation) of soils using sieve analysis. ASTM D6913, ASTM International, West Conshohocken, PA, USA

    Google Scholar 

  • Bazyar MH, Ghorbani A, Katzenbach R (2009) Small-scale model test and three dimensional analysis of pile-raft foundation on medium-dense sand. International Journal of Civil Engineering 7(3):170–175

    Google Scholar 

  • Burland JB (1995) Piles as settlement reducers. 18th Italian congress on soil mechanics, Pavia, Italy, 21–34

  • Burland JB, Broms BB, De Mello VFB (1977) Behavior of foundations and structures. Proceedings of 13th international conference on soil mechanics and foundation engineering, January 5–10, New Delhi, India, 495–546

  • Cerato AB, Lutenegger AJ (2006) Bearing capacity of square and circular footings on a finite layer of granular soil underlain by a rigid base. Journal of Geotechnical and Geoenvironmental Engineering 132(11):1496–501

    Article  Google Scholar 

  • Clancy P, Randolph MF (1993) An approximate analysis procedure for piled raft foundations. International Journal for Numerical and Analytical Methods in Geomechanics 17:849–869

    Article  Google Scholar 

  • Conte G, Mandolini A, Randolph MF (2003) Centrifuge modelling to investigate the performance of piled rafts. Proceedings of the 4th international geotechnical seminar on deep foundations on bored and auger piles, June 2–4, Ghent, Belgium, 359–366

  • Cooke RW (1986) Piled raft foundations on stiff clays, A contribution to design philosophy. Géotechnique 36(2):169–203

    Article  Google Scholar 

  • Davis E, Poulos H (1972) The analysis of pile raft systems. Australian Geomechanics Journal 1(62):21–27

    Google Scholar 

  • Dutta TT, Saride S (2015) Effect of confining pressure, relative density and shear strain on the poisson’s ratio of clean sand. 50th proceedings of Indian geotechnical conference EI Sawwaf M (2010) Experimental study of eccentrically loaded raft with connected and unconnected short piles. Journal of Geotechnical and Geoenvironmental Engineering 136(10):394–402, DOI: https://doi.org/10.1061/(ASCE)GT.1943-5606.0000341

    Google Scholar 

  • El-Garhy B, Galil AA, Youssef A, Raia MA (2013) Behavior of raft on settlement reducing piles: Experimental model study. Journal of Rock Mechanics and Geotechnical Engineering 5(5):389–399, DOI: https://doi.org/10.1016/j.jrmge.2013.07.005

    Article  Google Scholar 

  • Fioravante V, Giretti D (2010) Contact versus noncontact piled raft foundations. Canadian Geotechnical Journal 47(11):1271–1287, DOI: https://doi.org/10.1139/T10-021

    Article  Google Scholar 

  • Giretti D (2010) Modelling of piled raft foundations in sand. PhD Thesis, University of Ferrara, Ferrara, Italy

    Google Scholar 

  • Gok S (2007) Design of piled raft foundation. PhD Thesis, Istanbul Technical University, Istanbul, Turkey

    Google Scholar 

  • Horikoshi K, Randolph MF (1996) Centrifuge modelling of piled raft foundations on clay. Geotechnique 46(4):741–752

    Article  Google Scholar 

  • Huang M, Liang FY, Li Z (2007) Recent advances of pile foundation in China. Proceedings of the international workshop on recent advances of deep foundations, February 1–2, Yokosuka, Japan, 15–124

  • Kumar A, Choudhury D, Katzenbach R (2016) Effect of earthquake on combined pile-raft foundation. International Journal of Geomechanics 16(5), DOI: https://doi.org/10.1061/(ASCE)GM.1943-5622.0000637

  • Kwon O (2007) Load sharing ratio of raft in piled raft on granular soils by model test. Journal of the Korean Geoenvironmental Society 8(3):67–75

    Google Scholar 

  • Lee SH, Chung C (2005) An experimental study of the interaction of vertically loaded pile groups in sand. Canadian Geotechnical Journal 42(5):1485–1493, DOI: https://doi.org/10.1139/t05-068

    Article  Google Scholar 

  • Lee J, Park D, Choi K (2014) Analysis of load sharing behavior for piled rafts using normalized load response model. Computers and Geotechnics 57:65–74, DOI: https://doi.org/10.1016/j.compgeo.2014.01.003

    Article  Google Scholar 

  • Lee J, Park D, Park D, Park K (2015) Estimation of load-sharing ratios for piled rafts in sands that include interaction effects. Computers and Geotechnics 63:306–314, DOI: https://doi.org/10.1016/j.compgeo.2014.10.014

    Article  Google Scholar 

  • Lee J, Salgado R (1999) Determination of pile base resistance in sands. Journal of Geotechnical and Geoenvironmental Engineering, 125(8): 673–683, DOI: https://doi.org/10.1061/(ASCE)1090-0241(1999)125:8(673)

    Article  Google Scholar 

  • Lee J, Salgado R (2005) Estimation of bearing capacity of circular footings on sands based on cone penetration test. Journal of Geotechnical and Geoenvironmental Engineering 131(4):442–452, DOI: https://doi.org/10.1061/(ASCE)1090-0241(2005)131:4(442)

    Article  Google Scholar 

  • Liang FY, Chen LZ, Shi XG (2003) Numerical analysis of composite piled raft with cushion subjected to vertical load. Computers and Geotechnics 30(6):443–453, DOI: https://doi.org/10.1016/S0266-352X(03)00057-0

    Article  Google Scholar 

  • Liang FY, Li J, Chen LZ (2006) Optimization of composite piled raft foundation with varied rigidity of cushion. GeoShanghai international conference 2006, June 6–8, Shanghai, China, 29–34, DOI: https://doi.org/10.1061/40865(197)3

  • Nguyen DDC, Jo SB, Kim DS (2013) Design method of piled-raft foundations under vertical load considering interaction effects. Computers and Geotechnics 47:16–27, DOI: https://doi.org/10.1016/j.compgeo.2012.06.007

    Article  Google Scholar 

  • Park D, Lee J (2014) Comparative analysis of various interaction effects for piled rafts in sands using centrifuge tests. Journal of Geotechnical and Geoenvironmental Engineering 141(1), DOI: https://doi.org/10.1061/(ASCE)GT.1943-5606.0001183

  • Phung DL (1993) Footings with settlement-reducing piles in non-cohesive soil. PhD Thesis, Chalmers University of Technology, Gothenburg, Sweden

    Google Scholar 

  • Poulos HG (1991) Analysis of piled strip foundations. In: Proceedings of conference on computer methods and advances in geomechanics. Balkema, Rotterdam, The Netherlands, 183–191

    Google Scholar 

  • Poulos HG (2002) Simplified design procedure for piled raft foundations. International deep foundations congress 2002, February 14–16, Orlando, FL, USA, 441–458

  • Poulos HG, Davis EH (1980) Pile foundation analysis and design. Wiley, New York, NY, USA

    Google Scholar 

  • Randolph MF (1994) Design methods for pile groups and piled rafts: State-of-the-art report. Proceedings of the 13th international conference on soil mechanics and foundations engineering, January 5–10, New Delhi, India, 61–82

  • Rodriguez RE, Cunha RP, Caicedo HB (2019) Analysis of settlements in piled raft systems founded in soft soil under consolidation process. Canadian Geotechnical Journal, DOI: https://doi.org/10.1139/cgj-2018-0702

  • Roh Y, Kim I, Kim G, Lee J (2019) Comparative analysis of axial load capacity for piled-raft foundation with changes in groundwater level. KSCE Journal of Civil Engineering 23(10):4250–4258, DOI: https://doi.org/10.1007/s12205-019-0239-3

    Article  Google Scholar 

  • Sawada K, Takemura J (2014) Centrifuge model tests on piled raft foundation in sand subjected to lateral and moment loads. Soil and Foundations 54(2):126–140, DOI: https://doi.org/10.1016/j.sandf.2014.02.005

    Article  Google Scholar 

  • Schanz T, Veermer PA (1996) Angles of friction and dilatancy of sand. Geotechnique 46(1):145–151

    Article  Google Scholar 

  • Sharafkhah M, Shooshpasha I (2018) Physical modeling of behaviors of cast-in-place concrete piled raft compared to free-standing pile group in sand. Journal of Rock Mechanics and Geotechnical Engineering 10(4):703–716, DOI: https://doi.org/10.1016/j.jrmge.2017.12.007

    Article  Google Scholar 

  • Sinha A, Hanna AM (2016) 3D numerical model for piled raft foundation. International Journal of Geomechanics 17(2), DOI: https://doi.org/10.1061/(ASCE)GM.1943-5622.0000674

  • Turek J, Katzenbach R (2003) Small scale model tests with combined piled raft foundations. IDeep foundations on bored and auger piles: Proceedings of the 4th international geotechnical seminar on deep foundations on bored and auger piles, June 2–4, Ghent, Belgium

  • Viggiani C (1998) Pile groups and piled rafts behavior. In: Deep foundations on bored and auger piles. Balkema, Rotterdam, The Netherlands, 77–90

    Google Scholar 

  • Wong IH, Chang MF, Cao XD (2000) Raft foundations with disconnected settlement-reducing piles. In: Design applications of raft foundations. Thomas Telford Ltd., London, UK, 469–486

    Chapter  Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Dept. of Civil Engineering, Karadeniz Technical University, Trabzon, 61080, Turkey

    Bayram Ateş & Erol Şadoğlu

Authors
  1. Bayram Ateş
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Erol Şadoğlu
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Bayram Ateş.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Ateş, B., Şadoğlu, E. Experimental and Numerical Investigation of Load Sharing Ratio for Piled Raft Foundation in Granular Soils. KSCE J Civ Eng 26, 1662–1673 (2022). https://doi.org/10.1007/s12205-022-1022-4

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s12205-022-1022-4

Keywords

Search

Navigation