Equivalent Unbonded Length for Modeling of Multistrand Tendons in Precast Segmental Construction
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Volume 19, Issue 1
Abstract
Recently issued seismic design guidelines for precast segment construction require nonlinear modeling of segment-to-segment joints of important bridges. The response of segment joints is highly dependent on the length of debonding of the multistrand tendon. Neither the seismic design guidelines nor the literature provide sufficient guidance on how to determine the equivalent unbonded length of such tendons. This paper presents key results and conclusions of a large-scale experimental research program that investigated the debonding characteristics of multistrand tendons. Results indicate that tendon slip relative to the grout is small in comparison with slip between the duct and the surrounding concrete. An equation to evaluate the equivalent unbonded length of multistrand tendons was developed with direct application to modeling of the segment joint response.
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Acknowledgments
This research project was made possible by funding from the California Department of Transportation under Contract No. 59A0662. The input of Dr. Charly Sikorsky and others at CALTRANS was greatly appreciated. The authors also acknowledge Dywidag Systems International (DSI) for donating posttensioning materials and CMC Fontana Steel for donating the reinforcing bars for the experiments. The experiments presented in this paper could not have been completed without the hard work, dedication, and contributions of Fernando Pacheco, Matthew Tobolski, Andrew Gunthardt, Chris Latham, Paul Greco, and the staff at the Charles Lee Powell Structural Systems Laboratory. Their efforts are gratefully acknowledged.
References
AASHTO. (2012). AASHTO LRFD bridge design specifications: Customary U.S. units, 6th Ed., Washington, DC.
American Concrete Institute (ACI). (2005a). “Building code requirements for structural concrete.” ACI 318-05, Farmington Hills, MI.
American Concrete Institute (ACI). (2005b). “Building code requirements for structural concrete: Commentary.” ACI 318R-05, Farmington Hills, MI.
American Segmental Bridge Institute (ASBI) Grouting Committee. (2000). Interim statement on grouting practices, Phoenix.
CALTRANS. (2006). Standard specifications, Sacramento, CA.
Florida DOT (FDOT). (2007). Standard specifications for road and bridge construction, Tallahassee, FL.
Ghosh, S. K., and Fintel, M. (1986). “Development of prestressing strands, including debonded strands, and allowable concrete stress in pretensioned members.” PCI J., 31(5), 38–57.
Mattock, A. H. (1979). “Flexural strength of prestressed concrete sections by programmable calculator.” PCI J., 24(1), 32–54.
Naaman, A. E. (2012). Prestressed concrete analysis and design: Fundamentals, 3rd Ed., Techno Press 3000, Ann Arbor, MI.
Ramirez, J. A., and Russell B. W. (2007). “Transfer, development, and splice length for strand/reinforcement in high-strength concrete.” NCHRP Rep. 603, National Cooperative Highway Research Program, Washington, DC.
Russell, B. W., and Burns, N. H. (1996). “Measured transfer lengths of 0.5 and 0.6 in. strands in pretensioned concrete.” PCI J., 41(5), 44–65.
Schokker, A. J., Koester, B. D., Breen, J. E., and Kreger, M. E. (1999). “Development of high performance grouts for bonded post-tensioned structures.” Research Rep. 1405-2, Center for Transportation Research, Univ. of Texas at Austin, Austin, TX.
Tabatabai, H., and Dickson, T. J. (1993). “The history of the prestressing strand development length equation.” PCI J., 38(6), 64–75.
Veletzos, M. J., and Restrepo, J. I. (2009). “Influence of vertical earthquake motion and pre-earthquake stress on joint response of precast concrete segmental bridges.” PCI J., 54(3), 99–128.
Veletzos, M. J., and Restrepo, J. I. (2011a). “Development of seismic design guidelines for segmental construction.” Structural Systems Research Project Rep. SSRP-10/02, Dept. of Structural Engineering, Univ. of California, San Diego, La Jolla, CA.
Veletzos, M. J., and Restrepo, J. I. (2011b). “Modeling of jointed connections in segmental bridges.” J. Bridge Eng., 16(1), 139–147.
Zia, P., and Mostafa, T. (1977). “Development length of prestressing strands.” PCI J., 22(5), 54–65.
Information & Authors
Information
Published In
Journal of Bridge Engineering
Volume 19 • Issue 1 • January 2014
Pages: 101 - 109
Copyright
© 2014 American Society of Civil Engineers.
History
Received: Aug 22, 2012
Accepted: Apr 30, 2013
Published online: May 2, 2013
Published in print: Jan 1, 2014
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