New Method for Prediction Pile Capacity Executed by Continuous Flight Auger (CFA)
- 1 Faculty of Engineering, Sinai University, El Arish, Egypt
Abstract
A study of piles is quit complex and the estimation of carrying capacity is calculated fro m theoretical formula and load test results. The design resistance may be calculated using conventional static pile design theory. The pile founding depths should be predetermined before installation from a site geotechnical investigation. To ascertain the field per formance and estimate load carrying capacities of piles, in-situ pile load tests should be conducted. In this study, field pile load test data is analyzed to estimate the ultimate load for end bearing piles. The investigated site is about 100 × 110 m located in Alexandria, Egypt. Geotechnical investigations at the site are carried out to a maximum depth of 45 m. Four borings have been done in field. The tests are conducted at the site for two skelton structure buildings to be con structed on raft foundation rested on piles executed by continuous flight auger. Four pile load tests are performed on 600 mmdiameters and 27 mlengths. Ultimate capacities of piles are determined according to different methods. It i s concluded that the percentage of friction load carried by the shaft along the pile length is about 46% of total load while the percentage of load carried by the end bearing is 54% of total load. A new proposed method by the author is pre sented to calculate the ultimate capacity of pile from pile load test. The proposed method depends on the settlement of pile without taken into consideration the elastic deformation. An empirical formula is presented from the relationship between stress and settlement of pile due to friction and end bearing only after deducting the elastic deformation. How ever, the obtained results for the ultimate capacity of end bearing piles are considered to be more accurate than other methods. The proposed method appears to give bitter results that agrees well with the theoretical predictions. The pro posed method is easier, quicker and more reliable.
- T. Y. C. Ir, C. M. G. Chow and S. B. Partners, “Design & Construction of Bored Pile Foundation,” Geotechnical Course for Pile Foundation Design & Construction, Ipoh, 29-30 September 2003, pp. 1-74.
- A. B. Dan, D. D. Steven, W. T. Robert and A. L. Carlos “Design and Construction of Continuous Flight Auger (CFA) Piles,” Geotechnical Engineering Circular No. 8. April Office of Technology Application Office of Engineering/Bridge, Division Federal Highway Administration, US Department of Transportation, Washington DC, 2007, pp. 33-65.
- A. Akbar, S. Khilji, S. B. Khan, M. S. Qureshi and M. Sattar, “Shaft Friction of Bored Piles in Hard Clay,” Pakistan Journal of Engineering and Applied Science, Vol. 3, No. 3, 2008, pp. 54-60.
- K. Ishihara, “Recent Advances in Pile Testing and Diaphragm Wall Construction in Japan,” Geotechnical Engineering Journal of the SEAGS & AGSSEA, Vol. 41, No. 3, 2010, pp. 1-43.
- M. Suman and Y. Noriyuki, “End Bearing Capacity of Tapered Piles in Sands using Cavity Expansion Theory,” Memoirs of the Faculty of Engineering, Kyushu University, Vol. 71, No. 4, 2011, pp. 77-99.
- W. N. Elsamee, “Evaluation of the Ultimate Capacity of Friction Piles,” Engineering, Vol. 4 No. 11, 2012, pp. 778-789. doi:10.4236/eng.2012.411100
- Egyptian Code, “Soil Mechanics and Foundation,” Organization, Cairo, 2005.
- J. B. Hansen, “Discussion on Hyperbolic Stress-Strain Response, Cohesive Soils,” Journal for Soil Mechanics and Foundation Engineering, Vol. 89, 1963, pp. 241-242.
- F. K. Chin, “Estimation of the Ultimate Load of Piles from Tests Not Carried to Failure,” Proceedings of Second Southeast Asian Conference on Soil Engineering, Singapore, 11-15 June 1970, pp. 81-92.
- D. M. Dewaikar and M. J. Pallavi, “Analysis of Pile Load Tests Data” Journal of Southeast Asian Geotechnical Society, Vol. 89, No. 4, 2000, pp. 27-39.
- M. Das Braja, “Principle of Foundation Engineering,” 7th Edition, USA Cengage Brain.com, 2011.
- NAVFAC, DM-7.2, “Foundations and Earth Structures,” Design Manual, Department of the Navy Facilities Engineering Command, Alexandria, 1982.