Bond Behavior of the ETS FRP Bar Shear-Strengthening Method
Publication: Journal of Composites for Construction
Volume 16, Issue 5
Abstract
The embedded through-section (ETS) technique was recently developed to avoid the debonding failure that occurs with other fiber-reinforced polymer (FRP) strengthening techniques, such as the externally bonded (EB) and near-surface-mounted (NSM) methods. The method offers greater confinement and leads, therefore, to a substantial improvement in bond performance. In addition, it requires less concrete preparation than the EB strengthening technique. In this study, experimental results from 13 direct-shear test specimens are reported. The influence of the following major parameters on the bond behavior of FRP-strengthened reinforced concrete beams is examined: concrete strength, hole diameter, bar diameter, bar surface area, and bar bond length. The experimental results show that debonding can be avoided by providing a sufficient bar length and high concrete strength. Among the analytical models suggested in the literature for the bond behavior of FRP reinforced concrete, the Eligehausen, Popov, and Bertero (BPE) modified model and the Cosenza, Manfredi, and Realfonzo (CMR) model are compared with the experimental results obtained here. The CMR model with new fitting parameters is found to be an accurate way of simulating the experimental results. A new equation that accounts for concrete compressive strength and bar diameter is provided to estimate the development length.
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Acknowledgments
The financial support of the Natural Sciences and Engineering Research Council of Canada (NSERC), the Fonds Québécois de la Research sur la Nature et les Technologies (FQRNT), and the Ministère des Transports du Québec (MTQ) through operating grants is gratefully acknowledged. The authors thank Sika Canada Inc. (Pointe Claire, Quebec) for their contribution towards the cost of CFRP rods. The efficient collaboration of John Lescelleur (senior technician) and Juan Mauricio Rios (technician) of the École de Technologie Supérieure in conducting the tests is also acknowledged.
References
Achillides, Z., and Pilakoutas, K. (2004). “Bond behavior of fiber reinforced polymer bars under direct pullout conditions.” J. Compos. Constr., 8(2), 173–181.
American Concrete Institute (ACI). (2003). “Guide for the design and construction for structural concrete reinforced with FRP bars.” Rep. No., Framington Hills, MI.
American Concrete Institute (ACI). (2005). “Building code requirements for structural concrete.” and CommentaryReported by ACI Committee 318, Framington Hills, MI.
American Concrete Institute (ACI). (2006). “Guide for the design and construction for structural concrete reinforced with FRP bars.” Rep. No., Framington Hills, MI.
American Concrete Institute (ACI). (2008). “Guide for the design and construction of externally bonded FRP systems for strengthening concrete structures.” Rep. No., Framington Hills, MI.
ASTM. (2006). “Standard test method for tensile properties of fiber reinforced polymer matrix composite bars.”, West Conshohoken, PA.
ASTM. (2011a). “Standard test method for compressive strength of cylindrical concrete specimens.”, West Conshohoken, PA.
ASTM. (2011b). “Standard test method for splitting tensile strength of cylindrical concrete specimens.”, West Conshohoken, PA.
Baena, M., Torres, L., Turon, A., and Barris, C. (2009). “Experimental study of bond behaviour between concrete and FRP bars using a pull-out test.” Compos.: Part B, 40(8), 784–797.
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.
Canadian Standards Association (CSA). (2007). “Design and construction of building components with fiber-reinforced polymers.”, CAN/CSA, Rexdale, Canada.
Chaallal, O., Mofidi, A., Benmokrane, B., and Neale, K. W. (2011). “Embedded through-section FRP rod method for shear strengthening of RC beams: Performance and comparison with existing techniques.” J. Compos. Constr., 15(3), 374–383.
CIDAR. (2006). “Design guidelines for RC structures retrofitted with FRP and metal plates: Beams and slabs.”, Standards Australia, Sydney, Australia.
Cosenza, E., Manfredi, G., and Realfonzo, R. (1997). ‘‘Behavior and modeling of bond of FRP rebars to concrete.” J. Compos. Constr., 1(2), 40–51.
De Lorenzis, L., and Nanni, A. (2002). “Bond between NSM bar-reinforced polymer rods and concrete in structural strengthening.” ACI Struct. J., 99(2), 123–132.
Hassan, T., and Rizkalla, S. (2004). “Bond mechanism of near-surface mounted fiber reinforced polymer bars for flexural strengthening of concrete structures.” ACI Struct. J., 101(6), 830–839.
International Federation for Structural Concrete (fib). (2000). “Bond of reinforcement in concrete: State-of-the-art report.” Bulletin 10, Lausanne, Switzerland.
Japan Society of Civil Engineers (JSCE). (1997). “State-of-the-art report on continuous fiber reinforcing materials.”, Tokyo.
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.
Nanni, A., Al-Zahrani, M. M., Al-Dulaijan, S. U., Bakis, C. E., and Boothby, T. E. (1995). “Bond of FRP reinforcement to concrete: Experimental results.” Proc., 2nd Int. Rilem Symp. (FRPRCS-2), Taerwe, L.ed., E & FN SPON, London, England.
Novidis, D., and Pantazopoulou, S. (2008). “Bond tests of short NSM-FRP and steel bar anchorages.” J. Compos. Constr., 12(3), 323–333.
Pelligrino, C., and Modena, C. (2002). “Fiber reinforced polymer shear strengthening of RC beams with transverse steel reinforcement.” J. Compos. Constr., 6(2), 104–111.
Quantrill, R. J., Hollaway, L. C., and Thorne, A. M. (1996a). “Experimental and analytical investigation of FRP strengthened beam response: Part I.” Mag. Concr. Res., 48(177), 331–342.
Quantrill, R. J., Hollaway, L. C., and Thorne, A. M. (1996b). “Prediction of the maximum plate end stresses of FRP strengthened beams: Part II.” Mag. Concr. Res., 48(177), 343–351.
Soliman, S. M., El-Salakawy, E., and Benmokrane, B. (2011). “Bond performance of near-surface-mounted FRP bars.” J. Compos. Constr., 15(1), 103–111.
Taljsten, B., Carolin, A., and Nordin, H. (2003). “Concrete structures strengthened with near-surface mounted reinforcement of CFRP.” Adv. Struct. Eng., 6(3), 201–213.
Teng, J. G., Lu, X. Z., Ye, L. P., and Jiang, J. J. (2004). “Recent research on intermediate crack-induced debonding in FRP-strengthened RC beams.” Advanced composite materials in bridges and structures, El-Badry, M., and Dunaszegmi, L., eds., Canadian Society for Civil Engineering, Montreal, QC.
Tepfers, R. (2006). “Bond clause proposal for FRP-bars/rods in concrete based on CEB/FIB model code 90. Part 1: Design bond stress for FRP reinforcing bars.” Struct. Concr.: J. FIB, 7(2), 47–55.
Tepfers, R., and De Lorenzis, L. (2003). “Bond FRP reinforcement in concrete—A challenge.” Mech. Compos. Mater., 39(4), 315–328.
Tighiouart, B., Benmokrane, B., and Gao, D. (1998). “Investigation of bond in concrete member with fibre reinforced polymer (FRP) bars.” Constr. Build. Mater., 12(8), 453–462.
Triantafillou, T. C., and Plevris, N. (1992). “Strengthening of RC beams with epoxy bonded fiber-composite materials.” Mater. Struct., 25, 201–211.
Wahab, N., Soudki, K., and Topper, T. (2011). “Mechanism of bond behavior of concrete beams strengthened with near-surface mounted CFRP rods.” J. Compos. Constr., 15(1), 85–92.
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Information
Published In
Journal of Composites for Construction
Volume 16 • Issue 5 • October 2012
Pages: 529 - 539
Copyright
© 2012 American Society of Civil Engineers.
History
Received: Jun 6, 2011
Accepted: Jan 31, 2012
Published online: Sep 14, 2012
Published in print: Oct 1, 2012
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