Long-Term Monitoring of Strain in Instrumented Piles
Publication: Journal of Geotechnical and Geoenvironmental Engineering
Volume 135, Issue 11
Abstract
The development of strain in two 31 and 56 m long instrumented postdriving grouted cylinder piles at a site west of Busan, South Korea, were monitored during 200 days after construction, whereupon a static loading test was performed. Initial strain measurements showed unexpected elongation of the pile, probably due to swelling from absorption of water but as the soil reconsolidated, the elongation changed into shortening, probably due to imposed residual load in the pile. The resulting compression of the pile eventually offset the swelling of the pile. To investigate the cause of the strain changes more closely and enhance the evaluation of the field data, two short pile pieces were prepared and placed free-standing above ground in an outside laboratory. One piece was from a cylinder pile of which central void was grouted and one was made up by grouting inside a temporary casing. The monitoring showed that the short pieces appeared first to shorten and then to elongate due to the heating and cooling from the hydration process. When strains and temperature had stabilized 150 days after start of the study, both pieces were submerged to introduce swelling of the concrete. For the first 100 days after submerging, the swelling strains in both short pieces amounted to . Seven hundred days after submersion, the total swelling strains were 150 and .
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Acknowledgments
This work was supported by the Korea Science and Engineering Foundation (KOSEF) NRL program grant funded by the Korea government (MEST) (Grant No. UNSPECIFIEDR0A-2008-000-10323-0), and by Young Jo Engineering and Construction Co., Ltd., Seoul, Mr. Thomas Molnit at LOADTEST Asia Pte. Ltd., Dr. M.H. Lee at PILETECH, Seoul, and the postgraduate students at Dong-A University, Busan, who provided valuable assistance with the field tests.
References
Cusson, D., and Hoogeveen, T. (2007). “An experimental approach for the analysis of early-age behavior of high-performance concrete structures under restrained shrinkage.” Cem. Concr. Res., 37, 200–209.
Dunnicliff, J. (1988). Geotechnical instrumentation for monitoring field performance, Wiley, New York.
Geokon Inc. (1986). Instruction manual for model 4200/4202/4210 vibrating wire strain gages, Geokon Inc., Lebanon, New Hampshire, 24.
Mindess, S., Young, J. F., and Darwin, D. (1999). Concrete, 2nd Ed., Prentice-Hall, Upper Saddle River, N.J.
Powers, T. C. (1968). The properties of fresh concrete, Wiley, New York.
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© 2009 ASCE.
History
Received: Aug 9, 2008
Accepted: Apr 17, 2009
Published online: Oct 15, 2009
Published in print: Nov 2009
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