Modified Case Method for Piles with Section Step Changes
Publication: Journal of Geotechnical and Geoenvironmental Engineering
Volume 140, Issue 1
Abstract
Applied during pile driving, the Case Method offers an immediate estimate of the static resistance to driving (SRD) after each hammer blow. It has been used in its original form both in the onshore and offshore piling industries for more than 40 years to provide an indication of the pile static capacity. The Case Method requires measurements of force and velocity near the pile head as the hammer strikes the pile and produces an analytical estimate of the SRD using a number of assumptions, one of which requires the pile to be of constant impedance (or cross section) along its length. However, for reasons of economy, driven piles are often composed of several sections of different cross sections. In that case, the Case Method provides an inaccurate estimate of the SRD. This paper presents an improved version of the original Case Method, which takes into account possible variations of impedance along the pile. A numerical validation shows that for piles displaying impedance changes, the modified Case Method presented herein provides an estimate closer to the actual SRD than the original Case Method. That conclusion is further validated by applying the modified method to pile driving records and comparing its results to SRD estimates obtained through more reliable modeling.
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Acknowledgments
The authors express their appreciation to Fugro for providing the anonymous PDA records and geotechnical data pertaining to the practical case presented herein.
References
d’Alembert, J.-B. (1747). “Recherches sur la courbe que forme une corde tendue mise en vibration.” Histoire de l’académie royale des sciences et belles lettres de Berlin, Vol. 3, Haude et Spener, Berlin, 214–249.
de Chaunac, H., and Domange, J. (2011). “Etude de l’aspect cyclique dans la modélisation du battage des pieux.” M.S. thesis, Univ. catholique de Louvain, Louvain-la-Neuve, Belgium.
de Chaunac, H., and Holeyman, A. (2012). “Influence of an impedance change on SRD computation by the Case Method.” Proc., 9th Int. Conf. on Testing and Design Methods for Deep Foundations, T. Matsumoto, ed., Kanasawa, Kakuma-machi, Japan, 133–138.
de Saint-Venant, B. (1867). “Mémoire sur le choc longitudinal de deux barres élastiques de grosseurs et de matières semblables ou différentes, et sur la proportion de leur force vive qui est perdue pour la translation ultérieure; Et généralement sur le mouvement longitudinal d’un système de deux ou plusieurs prismes élastiques.” J. Math. Pures Appl., 2(12), 237–277.
Holeyman, A. E. (1992). “Keynote lecture: Technology of pile dynamic testing.” Proc., 4th Int. Conf. on the Application of Stress-Wave Theory to Piles, F. B. J. Barends, ed., Balkema, Rotterdam, Netherlands, 195–215.
Isaacs, D. V. (1931). “Reinforced concrete pile formulae.” J. Inst. Eng. Austral., 3(9), 305–323.
Likins, G. E., Jr., and Hussein, M. (1988). “A summary of the pile driving analyzer capacity methods, past and present.” Proc., 11th Pile Driving Analyzer User’s Seminar, Pile Dynamics, Cleveland, 1–23.
Rausche, F., and Goble, G. G. (1979). “Determination of pile damage by top measurements.” Behavior of deep foundations, ASTM STP 670, R. Lundgren, ed., ASTM, West Conshohocken, PA, 500–506.
Rausche, F., Goble, G. G., and Likins, G. E., Jr. (1985). “Dynamic determination of pile capacity.” J. Geotech. Engrg., 111(3), 367–383.
Salgado, R. (2008). “Pile driving analysis and quality control of piling operations.” Chapter 14, The engineering of foundations, McGraw Hill, New York, 669–713.
Smith, E. A. L. (1960). “Pile-driving analysis by the wave equation.” J. Soil Mech. and Found. Div., 86(4), 35–61.
Svinkin, M. R., and Abe, S. (1992). “Relationship between Case and hysteretic damping.” Proc., 4th Int. Conf. on the Application of Stress-Wave Theory to Piles, F. B. J. Barends, ed., Balkema, Rotterdam, Netherlands, 175–181.
Zhang, L., McVay, M. C., and Ng, C. W. W. (2001). “A possible physical meaning of Case damping in pile dynamics.” Can. Geotech. J., 38(1), 83–94.
Information & Authors
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Published In
Journal of Geotechnical and Geoenvironmental Engineering
Volume 140 • Issue 1 • January 2014
Pages: 102 - 109
Copyright
© 2014 American Society of Civil Engineers.
History
Received: Nov 26, 2012
Accepted: Jun 9, 2013
Published online: Jun 11, 2013
Published in print: Jan 1, 2014
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