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Numerical Analysis of Piled Raft Foundations Designed for Settlement Control on Steel Grain Silos in Collapsible Soils


The present article assesses the potential use of piled raft foundations for settlement control in grain silos, by performing numerical analyses with instrumented structures built in a particular city of the Mato Grosso state, deep in the Brazilian agricultural frontier. In this city, eight steel grain silos were constructed, and settlements were topographically monitored. The silos were numerically back analyzed using a finite-element-based hybrid numerical tool to verify interactions influence between the isolated (unpiled) foundation rafts during the grain storage season. A parametric analysis was subsequently carried out to verify the potential use of piled rafts to decrease settlement, as well as to improve design in terms of a better configuration concerning the use of compacted soil layers beneath the raft, raft thickness and pile length, and disposition within the foundation system. The numerical analyses indicated the use of a piled raft arrangement with a geometric factor equals to 0.09 as a proposed optimized solution aiming to minimize differential and total settlements. From this arrangement onwards, changes in pile spacing, pile diameter or in the number of piles, leading to higher geometric factors, were not able to provide significant settlement reductions. The increase in raft thickness and the use of compacted soil layers do not contribute to major improvements in the foundation settlement. The alternative optimized solution was able to ensure the serviceability and safety requirements of the silos, which can serve as a design benchmark.

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  1. 1.

    Dogangun A, Karaca Z, Durmus A, Sezen H (2009) Cause of damage and failures in silo structures. J Perform Constr Facil 23:65–71.

    Article  Google Scholar 

  2. 2.

    Poulos HG (1994) An approximate numerical analysis of pile-raft interaction. Int J Numer Anal Methods Geomech 18:73–92.

    Article  Google Scholar 

  3. 3.

    Conciani W (2016) Possíveis Melhoramentos no Projeto e Construção de Silos. Technical Report. Instituto Federal de Educação, Ciência e Tecnologia de Brasília. Brasília.

  4. 4.

    Mandolini A (2003) Design of Pile raft foundations: practice and development. In: 4th International Geotechnical Seminar on Deep Foundation on Bored and Auger Piles, pp 59–80

  5. 5.

    Poulos HG, Small JC, Chow H (2011) Piled Raft foundations for tall Buildings. Geotech Eng J SEAGS AGSSEA 42:78–84

    Google Scholar 

  6. 6.

    Soares WC, Coutinho RQ, da Cunha RP (2015) Piled raft with hollow auger piles founded in a Brazilian granular deposit. Can Geotech J 52:1005–1022.

    Article  Google Scholar 

  7. 7.

    Randolph MF (1994) Design methods for pile groups and piled rafts. In: International Conference on Soil Mechanics and Foundation Engineering. New Delhi, pp 61–82

  8. 8.

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

    Article  Google Scholar 

  9. 9.

    Azizkandi AS, Taherkhani R (2020) Experimental study on connected and non-connected piled raft foundations subjected to eccentric loading. Int J Civ Eng 18:743–761.

    Article  Google Scholar 

  10. 10.

    Baziar MH, Rafiee F, Lee CJ, Azizkandi AS (2018) Effect of superstructure on the dynamic response of nonconnected piled raft foundation using centrifuge modeling. Int J Geomech 18:1–10.

    Article  Google Scholar 

  11. 11.

    Kim KN, Lee SH, Kim KS et al (2001) Optimal pile arrangement for minimizing differential settlements in piled raft foundations. Comput Geotech 28:235–253.

    Article  Google Scholar 

  12. 12.

    Leung YF, Klar A, Soga K (2010) Theoretical study on pile length optimization of pile groups and piled rafts. J Geotech Geoenvironmental Eng 136:319–330.

    Article  Google Scholar 

  13. 13.

    Moayedi H, Nazir R, Ghareh S et al (2018) Performance analysis of a piled raft foundation system of varying pile lengths in controlling angular distortion. Soil Mech Found Eng 55:265–269.

    Article  Google Scholar 

  14. 14.

    Sales MM, Lima BS, Almeida SRM, Farias MM (2015) Automatic optimization of piled raft design based on branch and bound method. Struct Des Tall Spec Build 24:351–365.

    Article  Google Scholar 

  15. 15.

    Azizkandi AS, Kashkooli A, Baziar MH (2014) Prediction of uplift pile displacement based on cone penetration tests (CPT). Geotech Geol Eng 32:1043–1052.

    Article  Google Scholar 

  16. 16.

    Rabiei M, Choobbasti AJ (2020) Innovative piled raft foundations design using artificial neural network. Front Struct Civ Eng 14:138–146.

    Article  Google Scholar 

  17. 17.

    Sharafkhah M, Shooshpasha I (2018) A laboratory study of the effect of piles asymmetric arrangement on the behavior of piled raft foundation in sand. Int J Geotech Eng.

    Article  Google Scholar 

  18. 18.

    Fioravante V, Giretti D (2010) Contact versus noncontact piled raft foundations. Can Geotech J 47:1271–1287.

    Article  Google Scholar 

  19. 19.

    Sousa LCM, Cunha RP (2005) Estudo Experimental de Comportamento de Sapatas Estaqueadas Assentes em Solo Poroso colapsível. Soils Rocks 28:229–240

    Google Scholar 

  20. 20.

    Basile F (2015) Non-linear analysis of vertically loaded piled rafts. Comput Geotech 63:73–82.

    Article  Google Scholar 

  21. 21.

    Luo R, Yang M, Li W (2018) Normalized settlement of piled raft in homogeneous clay. Comput Geotech 103:165–178.

    Article  Google Scholar 

  22. 22.

    Huang M, Jiu Y, Jiang J, Li B (2017) Nonlinear analysis of flexible piled raft foundations subjected to vertical loads in layered soils. Soils Found 57:632–644.

    Article  Google Scholar 

  23. 23.

    Briançon L, Haza-Rosier E, Thorel L et al (2011) Recomendations for design, construction and control of rigid inclusion ground improvements. In: IREX Soil Specialist Cluster

  24. 24.

    Janda T, Cunha RP, Kuklik P, Anjos GM (2009) Three dimensional finite element analysis and back-analysis of CFA standard pile groups and piled rafts founded on tropical soil. Soils Rocks 32:3–18

    Google Scholar 

  25. 25.

    Katzenbach R, Arslan U, Moorman C, Reul O (1998) Piled raft foundations: interaction between piles and raft. Darmstadt Geotech 4:279–296

    Google Scholar 

  26. 26.

    Freitas Neto O, Cunha RP, Santos Junior OF et al (2013) Comparison of numerical methods for piled raft foundations. Adv Mater Res 838–841:334–341.

    Article  Google Scholar 

  27. 27.

    Móczár B, Mahler A, Lodör K, Bán Z (2016) Back analysis of settlements beneath the foundation of a sugar silo by 3D finite element method. Plaxis Bull, pp 12–17

  28. 28.

    Small JC, Poulos HG (2007) Non-linear analysis of piled raft foundations. Contemp Issues Deep Found Geotech Spec Publ 158:1–9.

    Article  Google Scholar 

  29. 29.

    Nguyen DDC, Jo SB, Kim DS (2013) Design method of piled-raft foundations under vertical load considering interaction effects. Comput Geotech 47:16–27.

    Article  Google Scholar 

  30. 30.

    Hain SJ, Lee IK (1978) The analysis of flexible raft-pile systems. Géotechnique 28:65–83.

    Article  Google Scholar 

  31. 31.

    Clancy P, Randolph MF (1993) An approximate analysis procedure for piled raft foundations. Int J Numer Anal Methods Geomech 17:849–869.

    Article  Google Scholar 

  32. 32.

    Ta LD, Small JC (1996) Analysis of piled raft systems in layered soils. Int J Numer Anal Methods Geomech 20:57–72.;2-0

    Article  MATH  Google Scholar 

  33. 33.

    Russo G (1998) Numerical Analysis of Piled Rafts. Int J Numer Anal Methods Geomech 22:477–493.;2-H

    Article  MATH  Google Scholar 

  34. 34.

    Kitiyodom P, Matsumoto T (2002) A simplified analysis method for piled raft and pile group foundations with batter piles. Int J Numer Anal Methods Geomech 26:1349–1369.

    Article  MATH  Google Scholar 

  35. 35.

    Kitiyodom P, Matsumoto T (2003) A simplified analysis method for piled raft foundations in non-homogeneous soils. Int J Numer Anal Methods Geomech 27:85–109.

    Article  MATH  Google Scholar 

  36. 36.

    Chow HSW, Small JC (2005) Behaviour of piled rafts with piles of different lengths and diameters under vertical loading. Adv Deep Found Geotech Spec Publ 132:1–15.

    Article  Google Scholar 

  37. 37.

    Bernardes HC, Carvalho SL, Sales MM et al (2019) Hybrid numerical tool for nonlinear analysis of piled rafts. Soils Found 59:1659–1674.

    Article  Google Scholar 

  38. 38.

    Cunha RP, Cordeiro AF, Sales MM, Small JC (2007) Parametric analyses of pile groups with defective piles: observed numerical behaviour and remediation. In: 10th Australia–New Zealand Conference on Geomechanics. Brisbane, pp 454–459

  39. 39.

    Cordeiro AFB, Cunha RP, Bezerra JE (2009) Numerical simulation of the installation of in additional pile in defective piled raft systems. In: Int. Conf. on Deep Foundations CPRF and Energy Piles. Frankfurt, pp 57–71

  40. 40.

    Cunha RP, Cordeiro AFB, Sales MM (2010) Numerical assessment of an imperfect pile group with defective pile both at initial and reinforced conditions. Soils Rocks 33:81–93

    Google Scholar 

  41. 41.

    Beygi M, Keshavarz A, Abbaspour M, Vali R (2019) 3D numerical study of the piled raft behaviour due to groundwater level changes in the frictional soil. Int J Geotech Eng.

    Article  Google Scholar 

  42. 42.

    Hassan M, Rafiee F, Azizkandi AS, Lee CJ (2018) Effect of super-structure frequency on the seismic behavior of pile-raft foundation using physical modeling. Soil Dyn Earthq Eng 104:196–209.

    Article  Google Scholar 

  43. 43.

    Teixeira AH, Godoy NS (1996) Análise, Projeto e Execução de Fundaçoes Rasas. Fundações Teoria e Prática. PINI, São Paulo, pp 227–264

    Google Scholar 

  44. 44.

    Vargas M (1978) Introdução à Mecânica dos Solos. Makron Books, São Paulo

    Google Scholar 

  45. 45.

    Cunha RP, Poulos HG, Small JC (2000) Parametric analysis of a piled raft case history in Uppsala. In: 4° Seminário de Engenharia de Fundações Especiais e Geotecnia. São Paulo, pp 380–387

  46. 46.

    Cunha RP, Poulos HG, Small JC (2001) Investigation of design alternatives for a piled raft case history. J Geotech Geoenvironmental Eng 127:635–641.

    Article  Google Scholar 

  47. 47.

    Sales MM (2000) Análise do comportamento de sapatas estaqueadas. Ph.D. thesis. Universidade de Brasília. Brasília-DF

  48. 48.

    Sales MM, Cunha RP, Carvalho JC, Silva CM (2002) Previsões de comportamento de um radier estaqueado no Distrito Federal. In: XII Cong. Bras. Mec. dos Solos e Engenharia Geotécnica - COBRAMSEG. São Paulo, pp 1459–1469

  49. 49.

    Sales MM, Small JC, Poulos HG (2010) Compensated piled rafts in clayey soils: behaviour, measurements and predictions. Can Geotech J 47:327–345.

    Article  Google Scholar 

  50. 50.

    Bahia GAD, Mota NMB, Cunha RP, Sales MM (2016) Avaliação do desempenho de fundações em edifício do Distrito Federal. In: XVIII Cong. Bras. Mec. dos Solos e Engenharia Geotécnica—COBRAMSEG. Belo Horizonte, pp 1–8

  51. 51.

    Poulos HG (1980) DEFPIG—deformation analysis of pile groups—User’s guide

  52. 52.

    Poulos HG (1989) Pile behaviour-theory and application. Géotechnique 39:365–415.

    Article  Google Scholar 

  53. 53.

    Sales MM, Curado TS (2018) Interaction factor between piles: limits on using the conventional elastic approach in pile group analysis. Soils Rocks 41:49–60.

    Article  Google Scholar 

  54. 54.

    Sanctis L, Mandolini A (2006) Bearing capacity of piled rafts on soft clay soils. J Geotech Geoenvironmental Eng 132:1600–1610.

    Article  Google Scholar 

  55. 55.

    Bjerrum L (1963) Allowable settlement of structures. In: 3rd European Conference on Soil Mechanics and Foundation Engineering. Wiesbaden, pp 135–137

  56. 56.

    Mylonakis G, Gazetas G (1998) Settlement and additional internal forces of grouped piles in layered soil. Géotechnique 48:55–72.

    Article  Google Scholar 

  57. 57.

    Silveira IA, Rodrigues RA (2020) Collapsible behavior of lateritic soil due to compacting conditions. Int J Civ Eng.

    Article  Google Scholar 

  58. 58.

    El-Garhy B, Galil AA, Youssef AF, Raia MA (2013) Behavior of raft on settlement reducing piles: experimental model study. J Rock Mech Geotech Eng 5:389–399.

    Article  Google Scholar 

  59. 59.

    Liu J, Huang Q, Li H, Hu WL (1994) Experimental research on bearing behaviour of pile groups in soft soil. In: 13th International Conference on Soil Mechanics and Foundation Engineering—ICSMFE, pp 535–538

  60. 60.

    Borel S (2001) Comportement et dimensionnement des fondations mixtes. ENPC, Ph.D. thesis, Spécialité Géotechnique, Paris

  61. 61.

    Décourt L, Quaresma AR (1978) Capacidade de Carga de Estacas a Partir de Valores de SPT. In: Proceedings of VI COBRAMSEF. Rio de Janeiro, pp 45–53

  62. 62.

    Terzaghi K (1943) Theoretical soil mechanics. Wiley, New York

    Book  Google Scholar 

  63. 63.

    Cooke RW (1986) Piled raft foundations on stiff clays—a contribution to design philosophy. Géotechnique 36:169–203.

    Article  Google Scholar 

  64. 64.

    O’Neill MW, Hawkins RA, Mahar L (1982) Load transfer mechanisms in piles and pile groups. J Geotech Eng Div 108:1605–1623

    Article  Google Scholar 

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The authors thank the University of Brasilia, in particular the Geotechnical Postgraduate Program for the support and infrastructure that allowed the elaboration of this research. A special attention should be given to the dear professor J.H.F. Pereira (in memory) for some ideas and discussions related to the research on tropical soils of the Brazilian Mid-West region. It should also be acknowledged the support given by the engineer M.Sc. José Antônio de Abreu and the engineering company EMBRE Engenharia LTDA for all foundation related research, especially to Dr. Carlos Medeiros. Also to the Brazilian sponsorship organizations CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico) and CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior) for the financial aid to our scholarships. This work is another product from the research group on foundations, in situ testing and retaining structures (


The Brazilian sponsorship organizations CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico) and CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior).

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Correspondence to Renato Pinto da Cunha.

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The data that support this study are available in (M.Sc. Thesis).

Code/Software Availability

The software was available by the last author (Prof. Renato Pinto da Cunha, Ph.D.), whose access was granted during his post-doctorate period in The University of Sidney, in 1999, with the Prof. Harry G. Poulos.

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Bernardes, H.C., de Souza Filho, H.L., Dias, A.D. et al. Numerical Analysis of Piled Raft Foundations Designed for Settlement Control on Steel Grain Silos in Collapsible Soils. Int J Civ Eng 19, 607–622 (2021).

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  • Piled raft
  • Grain silos
  • Numerical modeling
  • Foundation design
  • Collapsible soils
  • Settlement