Concrete Cover Separation in FRP-Plated RC Beams: Mitigation Using FRP U-Jackets
Publication: Journal of Composites for Construction
Volume 21, Issue 2
Abstract
Concrete cover separation is a common failure mode of RC beams strengthened with a fiber-reinforced polymer (FRP) plate externally bonded to the tension face (FRP-plated RC beams). This failure mode initiates at the critical plate end and then propagates at the level of steel tension reinforcement in the direction of increasing moment. Plate-end anchorage by FRP U-jackets has been specified in some design guidelines as a mitigation measure to delay or suppress concrete cover separation, although its effectiveness is far from clear. This mitigation method is more attractive than other options because the same strengthening material is used and the installation procedure is simple. This paper presents the first systematic experimental study on the use of FRP U-jackets for mitigating plate-end concrete cover separation failure, with particular attention to the effect of inclination angle between the U-jacket and the beam axis. A total of 10 full-scale FRP-plated RC beams were tested. The test results show that both the load-carrying capacity and the ductility of an FRP-plated RC beam can be significantly enhanced by FRP U-jacketing at the critical plate end. Inclined U-jacketing at 45° to the beam axis was found to be much more effective than vertical U-jacketing (i.e., at 90° to the beam axis) in mitigating plate-end cover separation failure.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
The authors are grateful for the financial support received from the Research Grants Council of the Hong Kong Special Administrative Region, China (Project No. PolyU 5315/09E) and the National Basic Research Program (i.e., 973 Program) (Project No. 2012CB026200) of China.
References
ACI (American Concrete Institute). (2008). “Guide for the design and construction of externally bonded FRP systems for strengthening concrete structures.” ACI 440.2R, Farmington Hills, MI.
ASTM. (2008). “Standard test method for tensile properties of polymer matrix composite materials.” ASTM D3039/D3039M-08, West Conshohocken, PA.
ASTM. (2010). “Standard test method for determining tensile properties of fiber reinforced polymer matrix composites used for strengthening of civil structures.” ASTM D7565/D7565M-10, West Conshohocken, PA.
Brena, S. F., Bramblett, R. M., Wood, S. L., and Kreger, M. E. (2003). “Increasing flexural capacity of reinforced concrete beams using carbon fiber-reinforced polymer composites.” ACI Struct. J., 100(1), 36–46.
BSI (British Standards Institute). (2009). “Metallic materials—Tensile testing. Part 1: Method of test at ambient temperature.” BS EN ISO 6892-1, London.
Buyle-Bodin, F., and David, E. (2004). “Use of carbon fibre textile to control premature failure of reinforced concrete beams strengthened with bonded CFRP plates.” J. Ind. Text., 33(3), 145–157.
Ceroni, F. (2010). “Experimental performances of RC beams strengthened with FRP materials.” Constr. Build. Mater., 24(9), 1547–1559.
Ceroni, F., and Pecce, M. (2010). “Evaluation of bond strength in concrete elements externally reinforced with CFRP sheets and anchoring devices.” J. Compos. Constr., 521–530.
Chen, J. F., and Teng, J. G. (2001). “Anchorage strength models for FRP and steel plates bonded to concrete.” J. Struct. Eng., 784–791.
China Planning Press. (2010). “Technical code for infrastructure application of FRP composites.” GB-50608, Beijing.
Concrete Society. (2012). “Design guidance for strengthening concrete structures using fibre composite materials.”, Crowthorne, U.K.
Garden, H. N., and Hollaway, L. C. (1998). “An experimental study of the influence of plate end anchorage of carbon fibre composite plates used to strengthen reinforced concrete beams.” Compos. Struct., 42(2), 175–188.
Hollaway, L. C., and Teng, J. G. (2008). Strengthening and rehabilitation of civil infrastructures using fibre-reinforced polymer (FRP) composites, Woodhead Publishing, Cambridge, U.K.
Kalfat, R., Al-Mahaidi, R., and Smith, S. T. (2013). “Anchorage devices used to improve the performance of reinforced concrete beams retrofitted with FRP composites: State-of-the-art review.” J. Compos. Constr., 14–33.
Kotynia, R., Baky, H. A., Neale, K. W., and Ebead, U. A. (2008). “Flexural strengthening of RC beams with externally bonded CFRP systems: Test results and 3D nonlinear FE analysis.” J. Compos. Constr., 190–201.
Lam, L., and Teng, J. G. (2001). “Strength of RC cantilever slabs bonded with GFRP strips.” J. Compos. Constr., 221–227.
Lee, J., Chacko, R., and Lopez, M. (2010). “Use of mixed mode fracture interfaces for the modeling of large scale FRP strengthened beams.” J. Compos. Constr., 845–855.
Lee, J., and Lopez, M. (2016). “Characterization of FRP Uwrap anchors for externally bonded FRP-reinforced concrete elements: An experimental study.” J. Compos. Constr., .
Leung, C. K. Y. (2006). “FRP debonding from a concrete substrate: Some recent findings against conventional belief.” Cem. Concr. Compos., 28(8), 742–748.
Lu, X. Z., Teng, J. G., Ye, L. P., and Jiang, J. J. (2007). “Intermediate crack debonding in FRP-strengthened RC beams: FE analysis and strength model.” J. Compos. Constr., 161–174.
Matthys, S. (2001). “Structural behaviour and design of concrete members strengthened with externally bonded FRP reinforcement.” Ph.D. thesis, Univ. of Ghent, Ghent, Belgium.
Orton, S. L., Jirsa, J. O., and Bayrak, O. (2008). “Design considerations of carbon fiber anchors.” J. Compos. Constr., 608–616.
Piamanmas, A., and Pornpongsaroj, P. (2004). “Peeling behaviour of reinforced concrete beams strengthened with CFRP plates under various end restraint conditions.” Mag. Concr. Res., 56(2), 73–81.
Raoof, M., and Hassanen, M. A. H. (2000). “Peeling failure of reinforced concrete beams with fibre-reinforced plastic or steel plates glued to their soffits.” ICE Proc. Struct. Build., 140(3), 291–305.
Reed, C. E., Peterman, R. J., and Rasheed, H. A. (2005). “Evaluating FRP repair method for cracked prestressed concrete bridge members subjected to repeated loadings (phase 1).”, Kansas Dept. of Transportation, Topeka, KS.
Ritchie, P. A., Thomas, D. A., Lu, L. W., and Connelly, G. M. (1991). “External reinforcement of concrete beams using fiber reinforcement plastic.” ACI Struct. J., 88(4), 490–500.
Rosenboom, O., and Rizkalla, S. H. (2008). “Experimental study of intermediate crack debonding in fiber-reinforced polymer strengthened beams.” ACI Struct. J., 105(1), 41–50.
Sallam, H. E. M., Saba, A. M., Shahin, H. H., and Abdel-Raouf, H. (2004). “Prevention of peeling failure in plated beams.” J. Adv. Concr. Technol., 2(3), 419–429.
Smith, S. T., and Teng, J. G. (2003). “Shear-bending interaction in debonding failures of FRP-plated RC beams.” Adv. Struct. Eng., 6(3), 183–199.
Teng, J. G., and Chen, J. F. (2009). “Mechanics of debonding in FRP-plated RC beams.” ICE Proc. Struct. Build., 162(5), 335–345.
Teng, J. G., Chen, J. F., Smith, S. T., and Lam, L. (2002). FRP-strengthened RC structures, Wiley, West Sussex, U.K.
Teng, J. G., Smith, S. T., Yao, J., and Chen, J. F. (2003). “Intermediate crack-induced debonding in RC beams and slabs.” Constr. Build. Mater., 17(6–7), 447–462.
Teng, J. G., and Yao, J. (2007). “Plate end debonding in FRP-plated RC beams—II: Strength model.” Eng. Struct., 29(10), 2472–2486.
Yao, J., and Teng, J. G. (2007). “Plate end debonding in FRP-plated RC beams—I: Experiments.” Eng. Struct., 29(10), 2457–2471.
Zhang, H. W., Smith, S. T., and Kim, S. J. (2012). “Optimisation of carbon and glass FRP anchor design.” Constr. Build. Mater., 32, 1–12.
Zhang, S. S. (2011). “Behaviour and modelling of RC beams strengthened in flexure with near-surface mounted FRP.” Ph.D. thesis, Hong Kong Polytechnic Univ., Hong Kong, China.
Zhang, S. S., and Teng, J. G. (2014). “Finite element analysis of end cover separation in RC beams strengthened in flexure with FRP.” Eng. Struct., 75(9), 550–560.
Information & Authors
Information
Published In
Copyright
©2016 American Society of Civil Engineers.
History
Received: Oct 27, 2015
Accepted: Apr 13, 2016
Published online: Aug 5, 2016
Discussion open until: Jan 5, 2017
Published in print: Apr 1, 2017
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.