Comparative Three-Dimensional Finite Element Analysis of Piled Raft Foundations

Document Type : Research Note

Authors

1 Civil Engineering,University of Tehran,Tehran,Iran

2 Department of Civil Engineering, Islamic Azad University, Ahvaz branch, Ahvaz, Iran

Abstract

3-dimensional finite element method as a general method to solve complex problems is one of the most powerful numerical methods which can be used for piled raft foundation analysis. These models can consider the complex interaction between soil and structure. Among available 3D FEM  software for modelling pield raft foundations, in this paper MIDAS GTS is used due to its various element type and modeling abilities. In this article, different pile modeling techniques in MIDAS GTS software (like pile modeling by solid elements, modeling by beam elements connected to soil elements and modeling by EPM  ) are compared with a real pile loading test data. Results showed that all three methods have excellent compatibility with the results of loading test in the linear area of the load-settlement curve, and SEM  and EPM kept their conformity further in the non-linear area as well. One of the most critical problems in 3D FEM modeling process of piled raft foundations with SEM was an increase in the number of elements when the number of piles increases and that leads to model's slowness and convergence problem. Piles modeling by EPM needs much lower elements; using this method, skin friction resistance, tip resistance and displacement between pile and soil can be easily calibrated with a pile loading test data which facilitates piled raft analysis with a large number of piles. After comparing different pile modeling techniques through MIDAS GTS software, the ability of the software for modeling piled raft foundations had been verified; Results show acceptable agreement between software output and monitored values and also outputs from other methods and software.

Highlights

Google Scholar

Keywords

Main Subjects


[1]     H. G. Poulos, “Pile-raft interaction–Alternative methods of analysis,” Dev. Theor. Geomech., pp. 445–463, 2000.
[2]     H. G. Poulos and E. H. Davis, Pile foundation analysis and design, no. Monograph. 1980.
[3]     M. F. Randolph, “Design methods for pile groups and piled rafts,” Proc. 13th ICSMGE, vol. 5, pp. 61–82, 1994.
[4]     W. F. Van Impe and Y. De Clerq, “A piled raft interaction model,” in Proc. 5th Intern. Conf. on Piling and Deep Foundations, 1994, p. 1.
[5]     J. B. Burland, “‘ Piles as settlement reducers,’ Invited Lecture,” XIX Convegno Ital. di Geotec., vol. 2, pp. 21–34, 1995.
[6]     H. G. Poulos, “An approximate numerical analysis of pile–raft interaction,” Int. J. Numer. Anal. Methods Geomech., vol. 18, no. 2, pp. 73–92, 1994.
[7]     P. Clancy and M. F. Randolph, “An approximate analysis procedure for piled raft foundations,” Int. J. Numer. Anal. Methods Geomech., vol. 17, no. 12, pp. 849–869, 1993.
[8]     C. S. Desai, “Numerical design-analysis for piles in sands,” J. Geotech. Geoenvironmental Eng., vol. 102, no. ASCE# 11893, 1976.
[9]     J. A. Hooper, “OBSERVATIONS ON THE BEHAVIOUR OF A PILE-RAFT FOUNDATION ON LONDON CLAY.,” Proc. Inst. Civ. Eng., vol. 55, no. 4, pp. 855–877, 1973.
[10]   P. Hewitt and S. S. Gue, “Piled Raft Foundation in a weathered sedimentary formation,” Proc. Geotropica, pp. 1–11, 1994.
[11]   R. Butterfield and P. K. Banerjee, “The elastic analysis of compressible piles and pile groups,” Geotechnique, vol. 21, no. 1, pp. 43–60, 1971.
[12]   J. Sinha and H. G. Poulos, “Piled raft systems and free standing pile groups in expansive soils,” in Proceedings 8th Australia New Zealand Conference on Geomechanics: Consolidating Knowledge, 1999, p. 207.
[13]   S. J. Hain and I. K. Lee, “The analysis of flexible raft-pile systems,” Geotechnique, vol. 28, no. 1, pp. 65–83, 1978.
[14]   L. D. Ta and J. C. Small, “Analysis of piled raft systems in layered soil,” Int. J. Numer. Anal. Methods Geomech., vol. 20, no. 1, pp. 57–72, 1996.
[15]   E. Franke, B. Lutz, and Y. El-Mossallamy, “Measurements and numerical modelling of high rise building foundations on Frankfurt clay,” in Vertical and Horizontal Deformations of Foundations and Embankments, 1994, pp. 1325–1336.
[16]   A. Sinha and A. M. Hanna, “3D numerical model for piled raft foundation,” Int. J. Geomech., vol. 17, no. 2, pp. 1–9, 2017.
[17]   P. Deb and S. K. Pal, “Numerical analysis of piled raft foundation under combined vertical and lateral loading,” Ocean Eng., vol. 190, no. September, p. 106431, 2019.
[18]   S. Mali and B. Singh, “Behavior of large piled-raft foundation on clay soil,” Ocean Eng., vol. 149, no. December 2017, pp. 205–216, 2018.
[19]   P. Deb and S. K. Pal, “Analysis of Load Sharing Response and Prediction of Interaction Behaviour in Piled Raft Foundation,” Arab. J. Sci. Eng., vol. 44, no. 10, pp. 8527–8543, 2019.
[20]   “Pile Foundation Design and Analysis | midas GTS NX.” [Online]. Available: https://en.midasuser.com/training/webinars_read.asp?pg=1&so=&sort=&bid=10&idx=8616. [Accessed: 28-May-2014].
[21]   D. Garber and E. Shahrokhinasab, “ABC-UTC Guide for: Full-Depth Precast Concrete (FDPC) Deck Panels,” vol. 1, no. May, p. 29, 2019.
[22]   D. Garber and E. Shahrokhinasab, “Performance Comparison of In-Service, Full-Depth Precast Concrete Deck Panels to Cast-in-Place Decks.” .
[23]   “12.2 Structural Interfaces.” [Online]. Available: https://dianafea.com/manuals/d944/ElmLib/node351.html. [Accessed: 28-May-2014].
[24]   P. Ghoddousi, A. M. Abbasi, E. Shahrokhinasab, and M. Abedin, “Prediction of Plastic Shrinkage Cracking of Self-Compacting Concrete,” Adv. Civ. Eng., vol. 2019, p. 1296248, 2019.
[25]   E. Shahrokhinasab, N. Hosseinzadeh, A. Monirabbasi, and S. Torkaman, “Performance of Image-Based Crack Detection Systems in Concrete Structures,” J. Soft Comput. Civ. Eng., vol. 4, no. 1, pp. 127–139, 2020.
[26]   O. Reul and M. F. Randolph, “Piled rafts in overconsolidated clay: comparison of in situ measurements and numerical analyses,” Geotechnique, vol. 53, no. 3, pp. 301–315, 2003.