Debonding Failures of RC Beams Strengthened with Near Surface Mounted CFRP Strips
Publication: Journal of Composites for Construction
Volume 10, Issue 2
Abstract
This paper presents the results of a series of tests conducted on reinforced concrete (RC) beams strengthened in flexure with near surface mounted (NSM) carbon fiber-reinforced polymer (CFRP) strips. As the main focus of the research is on debonding failure mechanisms, the only test variable investigated was the embedment length of the NSM strip and the NSM strip was extensively strain-gauged to monitor its bond behavior. Load-deflection curves, failure modes, strain distributions in the CFRP strip, and local bond stresses at the CFRP–epoxy interface from the tests are all examined in detail and compared with the predictions of a simple analytical model where appropriate. Of the four embedment lengths investigated, all but the shortest one led to a notable increase in the load-carrying capacity and, to a lesser extent, in the postcracking stiffness of the beam. Debonding was found to be the primary failure mode in all cases except for the beam with the longest embedment length. Also reported in this paper are results from preliminary bond tests used to characterize the local bond-slip behavior of the NSM system. Apart from gaining a better understanding of debonding failures in RC beams with NSM FRP strips, the test results reported in the paper should be useful for future verification of numerical and analytical models.
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Acknowledgments
The work presented in this paper has received financial support from the Research Grants Council of the Hong Kong SAR (PolyU 5173/04E) and The Hong Kong Polytechnic University (G31 YD 61). The writers are grateful to both organizations for their financial support.
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Information
Published In
Journal of Composites for Construction
Volume 10 • Issue 2 • April 2006
Pages: 92 - 105
Copyright
© 2006 ASCE.
History
Received: May 12, 2005
Accepted: Jul 28, 2005
Published online: Apr 1, 2006
Published in print: Apr 2006
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