Improved Evaluation of Equivalent Top-Down Load-Displacement Curve from a Bottom-Up Pile Load Test
Publication: Journal of Geotechnical and Geoenvironmental Engineering
Volume 137, Issue 6
Abstract
A modified procedure is presented in this study to evaluate the equivalent top-down load-displacement curve in a bottom-up pile load test considering elastic shortening. On the basis of the results of a parametric study on a bored pile in normally consolidated cohesive soils under undrained conditions, varying shear strength distribution and pile slenderness ratio, it was concluded that the pile shortening caused by the skin-friction component of the load in a top-down test can be related to the measured elastic shortening in a bottom-up test. A -factor is used to define this relationship, that is, the ratio of the top-down to bottom-up pile shortening. The factor is used for the case of a pile in soil with uniform shear strength profile, for linear profiles, for nonlinear profiles varying above linear, and for nonlinear profiles varying below linear. In addition, the method suggests taking the corresponding readings of the skin-friction load component from the upward displacement curve of the top of the pile, which is a closer approximation to rigid pile displacement than the bottom when corrections for elastic pile shortening are to be applied. Assuming a fully mobilized skin-friction, a logarithmic relation for the factor to the normalized area under the shear strength profile was generally formulated and is limited to the assumptions on which they were derived. The suggested procedure in this study has produced the equivalent top-down load-displacement curves that are in close agreement with the measured top-down curve, as validated in the case studies.
Get full access to this article
View all available purchase options and get full access to this article.
References
Baker, C. N. Jr. (1994). “Current U.S. design and construction practices for drilled piers.” Proc., 1st Int. Conf. on Design and Construction of Deep Foundation, Vol. 1, U.S. Federal Highway Administration, Washington, DC, 305–323.
Boulanger, R. W. (2003). “The TzSimple1 material.” 〈http://opensees.berkeley.edu/wiki/index.php/TzSimple1_Material〉 (Dec. 17, 2008).
Fleming, W. G. K. (1992). “A new method for single pile settlement prediction and analysis.” Geotechnique, 42(3), 411–425.
Gannon, J. A., Masterton, G. G. T., Wallace, W. A., and Muir Wood, D. (1999). “Pile foundations in weak rock.” Rep. No. 181, Construction Industry Research and Information Association (CIRIA), London.
Hossain, M. S., Omelchenko, V., and Haque, M. A. (2007). “Capacity of rock socketed drilled shafts in Mid-Atlantic region.” Geotechnical special conference: Contemporary issues in deep foundations, Denver, CO, 18–21.
Kwon, O. S., Choi, Y., Kwon, O., and Kim, M. M. (2005). “Comparison of the bidirectional load test with the top-down load test.” Transportation Research Record 1936, Transportation Research Board, Washington, DC, 108–116.
Lee, J. S., and Park, Y. H. (2008). “Equivalent pile load-head settlement curve using a bi-directional pile load test.” Comput. Geotech., 35(2), 124–133.
Mesri, G. (1989). “A re-evaluation of using laboratory shear tests.” Can. Geotech. J., 26(1), 162–164.
O’Neil, M. W., and Reese, L. C. (1999). “Drilled shafts: Construction procedures and design methods.” Report No. FHWA-IF-99-025, US Dept. of Transportation, Federal Highway Administration, Washington, DC.
OpenSees (2000). “Open system for earthquake engineering simulation.” Pacific Earthquake Engineering Research Center, Univ. of California, Berkeley, CA, 〈http://opensees.berkeley.edu/〉 (Dec. 17, 2008).
Osterberg, J. O. (1984). “A new simplified method for load testing drilled shafts.” Foundation Drilling Magazine, 23(6), 9.
Osterberg, J. O. (1998). “The Osterberg load test method for bored and driven piles—The first ten years.” Proc., 7th Int. Conf. and Exhibition on Piling and Deep Foundations, Deep Foundations Institute, Vienna, Austria.
Peng, L. S., Koon, A. M., Page, R., and Lee, C. W. (1999). “Osterberg cell testing of piles.” Proc., Int. Conf. on Rail Transit, Association of Consulting Engineers, Singapore.
Russo, G., Recinto, B., Viggiani, C., and de-Sanctis, L. (2003). “A contribution to the analysis of Osterberg’s cell load test.” Proc., Deep Foundation on Bored and Auger Piles, Millpress, Rotterdam, Netherlands, 331–338.
Schertmann, J. H., and Hayes, J. A. (1997). “The Osterberg cell and bored pile testing—A symbiosis.” Proc., 3rd Int. Geotechnical Engineering Conf., Cairo Univ., Cairo, Egypt, 139–166.
Terzaghi, K., and Peck, R. B. (1967). Soil mechanics in engineering practice, Wiley, New York.
Waxse, J. A., Osterberg, J., and Qudus, O. (2004). “Drilled shaft value engineering delivers success to Wahoo, Nebraska Bridge.” Proc., ASCE/ADSC Geo-Support 2004: Int. Drilled Foundation Support Specialty Conf., ASCE, Reston, VA, 289–298.
Woo, S. Y., Jeong, S. S., Moon, I. S., and Lee, J. K. (2006). “Bearing capacity analysis of large diameter drilled shafts by Osterberg-cell load tests.” Proc., 2006 Korean Society of Civil Engineers Annual Conf., KSCE, Seoul, 1728–1732.
Zuo, G., Drumm, E. C., Islam, M. Z., and Yang, M. Z. (2004). “Numerical analysis of drilled shaft O-cell testing in mica schist.” Proc., ASCE/ADSC Geo-Support 2004: Int. Drilled Foundation Support Specialty Conf., ASCE, Reston, VA, 778–789.
Information & Authors
Information
Published In
Journal of Geotechnical and Geoenvironmental Engineering
Volume 137 • Issue 6 • June 2011
Pages: 568 - 578
Copyright
© 2011 American Society of Civil Engineers.
History
Received: Jan 20, 2009
Accepted: Sep 27, 2010
Published online: Oct 1, 2010
Published in print: Jun 1, 2011
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.