Analysis Over the Accuracy of Dynamic Formulas for Predicting Ultimate Load Capacity in Deep Foundations

  • Alcineide D. Pessoa Lecturer, State University of the Tocantina Region of Maranhão (UEMASUL), Imperatriz-MA, Brazil.
  • Gean Carlos L. Sousa Assistant Professor, Federal University of Maranhão (UFMA), São Luís-MA, Brazil.
  • Gérson J.M. Anjos Associate Professor, Federal University of Pará (UFPA), Belém-PA, Brazil.
  • Rodrigo C. Araujo Associate Professor, Federal University of Maranhão (UFMA), São Luís-MA, Brazil.
Keywords: Ultimate Capacity, Dynamic Equations, Deep Foundations, Root Means Squared Error

Abstract

In Civil Engineering, particularly in Geotechnics, several empirical methods, commonly referred to as dynamic equations, have been proposed for prediction of ultimate load capacity of driven piles. However, these formulas are admitted inaccurate and, so, there is a need to evaluate the results obtained by them. In this work a comparative analysis of the values ​​obtained by five dynamic equations (Janbu, Danish, Gates, FHWA-Gates and WSDOT) with actual ultimate load capacities (obtained through pile load tests at site) is made. Errors are measured using the root mean squared error and the correlation between the equation´s results and the measured values ​​is verified. The results showed important differences between the ultimate capacities obtained from the analyzed models and the real values verified in field tests. It was also verified a superiority, in terms of lower error and greater correlation, of the WSDOT and Danish formulas. Attempts were made to improve the methods. For this, coefficients were determined that, when multiplied by the results of the formulas, promoted a reduction in error. Once again, WSDOT presented best perform in terms of correlation and error.

References

. B.H. Fellenius. Basics of Foundation Design. British Columbia, 2020. http://www.fellenius.net/papers/401%20The%20Red%20Book,%20Basics%20of%20foundation%20design%202020.pdf

. B.M. Das. Principles of Foundation Engineering. Seventh Edition.Cengage Learning, Stamford, 2011.

. M.A. de L. Alves., F.D.R. Lopes., B.R. Danziger. "Métodos dinâmicos para previsão e controle do comportamento de estacas cravadas", Teoria e prática na Engenharia Civil; n.4, p. 12-22, 2004.

. J.F. Cabette. "Análise dos métodos semi-empíricos utilizados para estimativa da capacidade de carga de estacas pré-fabricadas com base em resultados de ensaios de carregamento dinâmico". Dissertation, University of São Paulo, 2014.

. J.C.A. Cintra., N. Aoki. Fundações por Estacas - Projeto Geotécnico. Oficina dos Texto, São Paulo, 2010.

. J.E. Bowles. Foundation Analysis and Design. 5th Edition, The McGraw-Hill Companies, Inc., New York, 1996.

. H.A.Azeredo. O Edifício Até Sua Cobertura. 2a Edition. Edgar Blucher, São Paulo, 1977.

. B.M. Das. Principles of the Geotechnical Engineering. 7th ed., Cengage Learning, Stamford, 2010.

. W.C. Hachich., F.F. Falconi., J. Saes., R.G.Q. Frota., C.S. Carvalho., S. Niyama. Fundações – Teoria e prática. Ed. Pini, ABMS/ABEF, 2ª. ed., São Paulo, 1998.

. D.D.A. Velloso., F.D.R. Lopes. FUNDAÇÕES. Oficina de textos, São Paulo, 2012.

. Associação Brasileira de Normas Técnicas. "NBR 6122: Projeto e execução de fundações". Rio de Janeiro, 2010.

. A.S. Vesic. "Bearing Capacity of Deep Foundations in Sand.National Academy of Sciences", Highway Research Board, Report No. 39, Washington D.C.; pp. 112-153,1963.

. W. Chan., Y. Chow., L. Liu. "Neural network: an alternative to pile driving formulas", Computers and geotechnics; vol. 17, no.2: 135-156, 1995.

. I. M. Lee., J.H. "Prediction of pile bearing capacity using artificial neural networks", Computers and Geotechnics; vol. 18, no.3: 189-200, 1996.

. T.A. Pham., H-B. Ly., V-Q Tran., L.V. Giap., H-L. T. Vu., H-A. T. Duong. "Prediction of Pile Axial Bearing Capacity Using Artificial Neural Network and Random Forest", Applied Sciences; 10(5):1871, 2020. https://doi.org/10.3390/app10051871

. A.D. Pessoa., G.C. L. Sousa., R.C. Araujo., G.J.M. Anjos. "Artificial Neural Network Model for Predicting Load Capacity of Driven Piles", Research, Society and Development; 10 (1):e12210111526, 2021. https://doi.org/10.33448/rsd-v10i1.11526.

. K. Terzaghi. Theoretical Soil Mechanics. John Wiley & Sons,, New York, 1943

. R. V. Gallegos. "Aplicabilidade da equação de onda e de fórmulas dinâmicas na estimativa da capacidade de carga em estacas". Dissertation, Pontifícia Universidade Católica do Rio de Janeiro, 2014.

. T. Sorensen., B. Hansen. "Pile driving formulae—an investigation based on dimensional considerations and a statistical analysis". In: Proceedings of 4th international conference soil mechanics and foundation engineering, 1957.

. B. O. Lobo. "Método de previsão de capacidade de carga de estacas : aplicação dos conceitos de energia do ensaio SPT". . Dissertação (Mestrado).

Programa de Pós-Graduação em Engenharia Civil. UFRGS, Porto Alegre, 2005.

. M.S. R. Jayaweera. "Capacity Estimation of Piles Using Dynamic Methods". Master of Engineering in Foundation Engineering &

Earth Retaining Systems. University of Moratuwa. Sri-Lanka, 2009.

. SCAC. "Case: conjunto residencial no Rio de Janeiro", 2013. <https://issuu.com/scacengenharia/docs/scac_case_conj_residencial_rj>

. J. Benesty., J. Chen., Y. Huang., I. Cohen. "Pearson correlation coefficient". In Noise reduction in speech processing (pp. 1-4). Springer, Berlin, Heidelberg, 2009.

. C.J. Willmott., K. Matsuura. "Advantages of the mean absolute error (MAE) over the root mean square error (RMSE) in assessing average model performance", Clim Res.; 30(1):79–82, 2005.

Published
2021-05-04
Section
Articles