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.
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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.
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Information & Authors
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Published In
Journal of Composites for Construction
Volume 21 • Issue 2 • April 2017
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
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