Performance of End-Anchorage Systems for RC Beams Strengthened in Shear with Epoxy-Bonded FRP
Publication: Journal of Composites for Construction
Volume 16, Issue 3
Abstract
This paper presents the results of an experimental investigation on the performance of full-scale reinforced concrete (RC) T-girders strengthened in shear using externally bonded (EB) fiber-reinforced polymer (FRP) U-jackets end-anchored with different systems. Debonding of FRP, particularly in shear, is a major failure mode when using FRP sheets to strengthen concrete structures. Design code provisions and guidelines related to shear-strengthening of RC beams using externally bonded FRP (EB FRP) suggest the use of end-anchorage systems to prevent FRP debonding. However, no guidelines are available for the design and effectiveness of end-anchorage systems. The main objective of this study is to evaluate the effectiveness of different end-anchorage systems for RC beams strengthened using EB FRP methods. To this end, nine tests were performed on 4520-mm-long RC T-beams. Four specimens were strengthened in shear using EB FRP methods with various end-anchorage systems, and their performance was compared with similar specimens strengthened with: (1) EB FRP with no anchorage; (2) near-surface-mounted (NSM) FRP rods; and (3) embedded through-section (ETS) FRP rods. The results of this study reveal that specimens retrofitted with EB FRP methods and properly designed end-anchorage systems can achieve a superior contribution to shear resistance compared with specimens strengthened using EB FRP with no anchorage, NSM, or ETS methods.
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Acknowledgments
The financial support of the Natural Science and Engineering Research Council of Canada, the Fonds québécois de la recherche sur la nature et les technologies (FQRNT Research Team Project), and the Ministére des Transports du Québec (MTQ) through operating grants to Amir Mofidi and Profs. Chaallal, Benmokrane, and Neale is gratefully acknowledged. The authors thank Sika Canada Inc. (Pointe Claire, Quebec) for their donation of the CFRP rods and laminates. The efficient collaboration of John Lescelleur (senior technician) and Juan Mauricio Rios (technician) at ETS in conducting the tests is also 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, Detroit.
Barros, J. A. O., and Dias, S. J. E. (2006). “Near surface mounted CFRP laminates for shear strengthening of concrete beams.” Cem. Concr. Compos., 28(3), 276–292.CCOCEG
Bousselham, A., and Chaallal, O. (2008). “Mechanisms of shear resistance of concrete beams strengthened in shear with externally bonded FRP.” J. Compos. Constr.JCCOF2, 12(5), 499–512.
Canadian Standards Association (CSA). (2002). “Design and construction of building components with fibre-reinforced polymers.” CAN/CSA S806-02 (R2007), Mississauga, ON, Canada.
Ceroni, F., Pecce, M., Matthys, S., and Taerwe, L. (2008). “Debonding strength and anchorage devices for reinforced concrete elements strengthened with FRP sheets.” Comp. Part B: Eng.CPBEFF, 39(3), 429–441.
Chaallal, O., Mofidi, A., Benmokrane, B., and Neale, K. (2011). “Embedded through-section FRP rod method for shear strengthening of RC beams: Performance and comparison with existing techniques.” J. Compos. Constr., 15(3), 374–384.JCCOF2
Chen, G. M., Teng, J. G., Chen, J. F., and Rosenboom, O. A. (2010). “Interaction between steel stirrups and shear-strengthening FRP strips in RC beams.” J. Compos. Constr.JCCOF2, 14(5), 498–509.
De Lorenzis, L., and Nanni, A. (2001). “Shear strengthening of reinforced concrete beams with FRP rods.” J. Comp. Constr., 5(2), 114–121.ASTJEG
Deniaud, C., and Cheng, J. J. R. (2004). “Simplified shear design method for concrete beams strengthened with fibre-reinforced polymer sheets.” J. Compos. Constr.JCCOF2, 8(5), 425–433.
Eshwar, N., Nanni, A., and Ibell, T. J. (2008). “Performance of two anchor systems of externally bonded fiber-reinforced polymer laminates.” ACI Mater. J., 105(1), 72–80.AMAJEF
International Federation for Structural Concrete (fib). (2001). “Externally bonded FRP reinforcement for RC structures.” fib Bulletin No. 14, Lausanne, Switzerland.
Khalifa, A., and Nanni, A. (2000). “Improving shear capacity of existing RC T-section beams using CFRP composites.” Cem. Concr. Compos.CCOCEG, 22(3), 165–174.
Mofidi, A. (2008). “Strengthening RC T-beams in flexure and shear using new mechanically-anchored FRP and dry fibre systems.” M.Sc. thesis, Concordia Univ., Montréal.
Mofidi, A., and Chaallal, O. (2011a). “Shear strengthening of RC beams with EB FRP: Influencing factors and conceptual debonding model.” J. Compos. Constr.JCCOF2, 15(1), 62–74.
Mofidi, A., and Chaallal, O. (2011b). “Shear strengthening of RC beams with externally bonded FRP composites: Effect of strip-width to strip-spacing ratio.” J. Compos. Constr.JCCOF2, 15(5), 732–743.
Sato, Y., Katsumata, H., and Kobatake, Y. (1997). “Shear strengthening of existing reinforced concrete beams by CFRP sheet.” Proc., 3rd Int. Symp. on Non-Metallic (FRP) Reinforcement for Concrete Structures, Japan Concrete Institute, Tokyo, 507–514.
Schuman, P. (2004). “Mechanical anchorage for shear rehabilitation of reinforced concrete structures with FRP: An appropriate design approach.” Ph.D. thesis, Univ. of California, San Diego.
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Information
Published In
Journal of Composites for Construction
Volume 16 • Issue 3 • June 2012
Pages: 322 - 331
Copyright
© 2012. American Society of Civil Engineers.
History
Received: May 16, 2011
Accepted: Oct 14, 2011
Published online: Oct 18, 2011
Published in print: Jun 1, 2012
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