Construction QA/QC Methods for Postgrouting Drilled Shafts
Publication: Journal of Performance of Constructed Facilities
Volume 30, Issue 4
Abstract
The design and anticipated end-bearing capacity of postgrouted drilled shafts hinge on achieving sufficient grout pressure applied to the soils beneath the shaft tip. Implied, however, is that the grout is distributed reasonably well across the entire tip area. To this end, minimum grout pressure and volume thresholds are usually prescribed in an effort to address both concerns. Unfortunately, it is difficult to practically ascertain the actual area of the grout bulb during production grouting when manually-recorded values of pressure, volume, and uplift are the only available information. Therein, artificially-high grout pressure can be recorded, resulting from a blocked grout-distribution system that goes undetected and the shaft is accepted as both the minimum pressure and volume criteria were satisfied. This article outlines minimum monitoring practices and field quality-assurance/quality-control (QA/QC) measures that can and should be used to better ensure tip grouting is performed in conformance with the designer’s expectations and intended outcome. The value of the proposed standard of care is highlighted through case studies where drilled shafts for bridge foundations were constructed, grouted, and met all acceptance criteria but where they were not grouted satisfactorily.
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Acknowledgments
The author would like to acknowledge that many contributors assisted in the findings of this article. Names have been excluded due to the sometimes controversial nature of grout and load test results.
References
Bittner, R., Safaqah, O., Zhang, X., and Jensen, O. (2007). “Design and construction of the Sutong bridge foundations.” DFI J., 1(1), 2–18.
Bolognesi, A. J. L., and Moretto, O. (1973). “Stage grouting preloading of large shafts on sand.” Proc., 8th Int. Conf. on Soil Mechanics and Foundation Engineering, Moscow, 19–25.
Bruce, D. A. (1986). “Enhancing the performance of large diameter shafts by grouting.”, Minerva Press, Brentwood, England.
Bruce, D. A., Nufer, P. J., and Triplett, R. E. (1995). “Enhancement of caisson capacity by micro-fine cement grouting—A recent case history.” Verification of geotechnical grouting, Geo-Institute, New York, 142–152.
Dapp, S., and Brown, D. (2010). “Evaluation of base grouted drilled shafts at the audubon bridge.” GeoFlorida 2010: Advances in Analysis, Modeling and Design, ASCE, Reston, VA, 1553–1562.
Dapp, S. D. (1998). “Personal communication with on-site engineers during load testing on the My Thuan Bridge.” Mekong Delta, Vietnam.
Dapp, S. D. (2002). “Pressure grouting of drilled shafts in sands.” Ph.D. dissertation, Univ. of South Florida, Tampa, FL.
Flemming, W. G. K. (1993). “The improvement of shaft performance by base grouting.” Proc. Inst. Civ. Eng., 97(2), 88–93.
Gouvenot, D., and Gabiax, F. D. (1975). “A new foundation technique using shafts sealed by concrete under high pressure.” Proc., 7th Annual Offshore Technology Conf., Vol. II, Houston, 645–654.
Mojabe, M. S., and Duffin, M. J. (1991). “Large diameter, rock socket, base grouted piles in Bristol.” Proc., 4th Int. Conf. on Piling and Deep Foundations, Vol. 1, A.A. Balkema, Brookfied, VT, 97–100.
Mullins, A. G. (1999). “Personal communication with on-site engineers during load testing on the Taipei Financial Center.” Taipei, Taiwan.
Mullins, G., Dapp, S., Frederick, E., and Wagner, R. (2001). “Pressure grouting drilled shaft tips.” Florida Dept. of Transportation, Tallahassee, FL.
Mullins, G., and O’Neill, M. (2003). “Pressure grouting drilled shaft tips—A full-scale load test program.”, Univ. of South Florida, Tampa, FL.
Mullins, G., and Winters, D. (2004). “Post grouting drilled shaft tips.” Florida Dept. of Transportation, Tallahassee, FL.
Mullins, G., Winters, D., and Dapp, S. (2006). “Predicting end bearing capacity of post grouted drilled shafts in cohesionless soils.” J. Geotech. Geoenviron. Eng., 478–487.
Piccione, M., Carletti, G., and Diamanti, L. (1984). “The pile foundations of the Al Gazira hotel in Cairo.” Proc., Int. Conf. on Advances in Piling and Ground Treatment for Foundations, Institution of Civil Engineers, London.
Reese, L. C., and O’Neill, M. W. (1988). “Drilled shafts: Construction and design.”, U.S. Dept. of Transportation, Washington, DC.
Santosuossa, M., Rizzi, G., and Diamanti, L. (1991). “Construction of pile foundation of the postal Cittadel in the direction center of Naples.” Proc., 4th Int. Conf. on Piling and Deep Foundations, Vol. 1, A.A. Balkema, Brookfied, VT, 123–132.
Sliwinski, Z. J., and Flemming, W. G. K. (1984). “The integrity and performance of bored piles.” Proc., Int. Conf. on Advancess in Piling and Ground Treatment for Foundations, Institution of Civil Engineers, London, 211–223.
Troughton, V. M., and Platis, A. (1989). “The effects of changes in effective stress on a base grouted pile in sand.” Proc., Int. Conf. on Piling and Deep Foundations, Vol. 1, A.A. Balkema, Brookfied, VT, 445–453.
Vesic’, A. S. (1967). “Ultimate loads and settlements of deep foundations in sand.” Proc., Symp. Held at Duke Univ., Duke Univ., Durham, NC.
Winters, D. (2014). “Selected topics in foundation design, quality assurance, and remediation.” Ph.D. dissertation, Univ. of South Florida, Tampa, FL.
Information & Authors
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Published In
Journal of Performance of Constructed Facilities
Volume 30 • Issue 4 • August 2016
Copyright
© 2015 American Society of Civil Engineers.
History
Received: Nov 14, 2014
Accepted: Jul 21, 2015
Published online: Oct 22, 2015
Discussion open until: Mar 22, 2016
Published in print: Aug 1, 2016
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