Shear Strengthening of RC Beams with Externally Bonded FRP Composites: Effect of Strip-Width-to-Strip-Spacing Ratio
Publication: Journal of Composites for Construction
Volume 15, Issue 5
Abstract
The results of an experimental and analytical investigation of shear strengthening of reinforced concrete (RC) beams with externally bonded (EB) fiber-reinforced polymer (FRP) strips and sheets are presented, with emphasis on the effect of the strip-width-to-strip-spacing ratio on the contribution of FRP (). In all, 14 tests were performed on 4,520-mm-long -beams. RC beams strengthened in shear using carbon FRP (CFRP) strips with different width-to-spacing ratios were considered, and their performance was investigated. In addition, these results are compared with those obtained for RC beams strengthened with various numbers of layers of continuous CFRP sheet. Moreover, various existing equations that express the effect of FRP strip width and concrete-member width and that have been proposed based on single or double FRP-to-concrete direct pullout tests are checked for RC beams strengthened in shear with CFRP strips. The objectives of this study are to investigate the following: (1) the effectiveness of EB discontinuous FRP sheets (FRP strips) compared with that of EB continuous FRP sheets; (2) the optimum strip-width-to-strip-spacing ratio for FRP (i.e., the optimum FRP rigidity); (3) the effect of FRP strip location with respect to internal transverse-steel location; (4) the effect of FRP strip width; and (5) the effect of internal transverse-steel reinforcement on the CFRP shear contribution.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
The financial support of the National Science and Engineering Research Council of Canada (NSERC)NSERC, the Fonds québécois de la recherche sur la nature et les technologies (FQRNT), and the Ministère des Transports du Québec (MTQ) through operating grants is gratefully acknowledged. The efficient collaboration of John Lescelleur (senior technician) and Juan Mauricio Rios (technician) at ÉTS, in conducting the tests, is acknowledged.
References
American Concrete Institute (ACI). (2008). “Guide for the design and construction of externally bonded FRP systems for strengthening concrete structures.” Rep. No. 440 2R-08, Farmington Hills, MI.
Bizindavyi, L., and Neale, K. W. (1999). “Transfer lengths and bond strengths for composites bonded to concrete.” J. Compos. Constr., 3(4), 153–160.
Bousselham, A., and Chaallal, O. (2004). “Shear strengthening reinforced concrete beams with fiber-reinforced polymer: Assessment of influencing parameters and required research.” ACI Struct. J., 101(2), 219–227.
Bousselham, A., and Chaallal, O. (2006). “Behavior of reinforced concrete -beams strengthened in shear with carbon fiber-reinforced polymer—An experimental study.” ACI Struct. J., 103(3), 339–347.
Brosens, K. (2001). “Anchorage of externally bonded steel plates and CFRP laminates for the strengthening of concrete elements.” Ph.D. dissertation, Department of Civil Engineering, Katholieke Universiteit Leuven, Leuven, Belgium.
Brosens, K., and van Gemert, D. (1999). “Anchorage design for externally bonded carbon fiber polymer laminates.” Proc., 4th Int. Symp. on Fiber Reinforced Polymer Reinforcement for Concrete Structures, ACI International, Baltimore, MD, 635–645.
CAN/CSA-S6-06. (2006). Canadian highway bridge design code, Canadian Standards Association, Mississauga, Canada.
CAN/CSA-S806-02. (2002). Design and construction of building components with fiber-reinforced polymer, Canadian Standards Association, Rexdale, Canada.
Chaallal, O., Shahawy, M., and Hassan, M. (2002). “Performance of reinforced concrete -girders strengthened in shear with carbon fiber-reinforced polymer fabric.” ACI Struct. J., 99(3), 335–343.
Chen, J. F., and Teng, J. G. (2001). “Anchorage strength models for FRP and steel plates bonded to concrete.” J. Struct. Eng., 127(7), 784–791.
Chen, J. F., and Teng, J. G. (2003). “Shear capacity of FRP strengthened RC beams: FRP debonding.” Constr. Build. Mater., 17(1), 27–41.
CNR-DT200. (2004). Guidelines for design, execution, and control of strengthening interventions by means of fiber-reinforced composites, National Research Council, Roma, Italy.
fib-TG 9.3. (2001). Externally bonded FRP reinforcement for RC structures, International Federation for Structural Concrete, Lausanne, Switzerland.
HB 305, Oehlers, D. J., Seracino, R., and Smith, S. T. (2008). “Design guideline for RC structures retrofitted with FRP and metal plates: Beams and slabs.” HB 305-2008, Standards Australia, Sydney, Australia, ISBN 0 7337 7831 3, 73.
Holzenkämpfer, O. (1994). “Ingenieurmodelle des Verbundes Geklebter Bewehrung für Betonbauteile.” Ph.D. thesis, TU Braunschweig, Germany.
Kamel, A. S., Elwi, A. E., and Cheng, J. J. R. (2000). “Experimental study of the behavior of CFRP sheets bonded to concrete.” Proc., 3rd Int. Conf. on Advanced Composite Materials for Bridges and Structures, Canadian Society for Civil Engineering, Ottawa, 61–68.
Khalifa, A., Gold, W. J., Nanni, A., and Aziz, A. (1998). “Contribution of externally bonded FRP to shear capacity of RC flexural members.” J. Compos. Constr., 2(4), 195–203.
Khalifa, A., and Nanni, A. (2000). “Improving shear capacity of existing RC -section beams using CFRP composites.” Cem. Concr. Compos., 22, 165–174.
Khalifa, A., and Nanni, A. (2002). “Rehabilitation of rectangular simply supported RC beams with shear deficiencies using CFRP composites.” Constr. Build. Mater., 16, 135–146.
Lima, J. L. T., and Barros, J. A. O. (2007). “Design models for shear strengthening of reinforced concrete beams with externally bonded FRP composites: A statistical versus reliability approach.” Proc., 8th Int. Symp. on Fiber Reinforced Polymer Reinforcement for Concrete Structures, University of Patras, Patras, Greece.
Mofidi, A., and Chaallal, O. (2010). “Shear strengthening of RC beams with EB FRP—Influencing factors and conceptual debonding model.” J. Compos. Constr., .
Neubauer, U., and Rostásy, F. S. (1997). Design aspects of concrete structures strengthened with externally bonded CFRP plates, ECS Publications, Edinburgh, 109–118.
Pellegrino, C., and Modena, C. (2002). “Fiber reinforced polymer shear strengthening of RC beams with transverse steel reinforcement.” J. Compos. Constr., 6(2), 104–111.
Pellegrino, C., and Modena, C. (2006). “Fiber-reinforced polymer shear strengthening of reinforced concrete beams: Experimental study and analytical modeling.” ACI Struct. J., 103(5), 720–728.
Triantafillou, T. C. (1998). “Shear strengthening of reinforced concrete beams using epoxy-bonded FRP composites.” ACI Struct. J., 95(2), 107–115.
Zhang, Z., and Hsu, C.-T. (2005). “Shear strengthening of reinforced concrete beams using carbon-fiber reinforced polymer laminates.” J. Compos. Constr., 9(2), 158–169.
Information & Authors
Information
Published In
Copyright
© 2011 American Society of Civil Engineers.
History
Received: Jul 13, 2010
Accepted: Mar 24, 2011
Published online: Mar 26, 2011
Published in print: Oct 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.