Modeling of IC Debonding of FRP-Strengthened Concrete Flexural Members
Publication: Journal of Composites for Construction
Volume 12, Issue 2
Abstract
The presence of a fiber-reinforced polymer (FRP) strengthening material bonded to the tension face of a reinforced concrete beam will restrict but not prevent the opening of intermediate flexural cracks due to applied loading. Test results indicate that displacements at the toe of flexural cracks create stress concentrations at the interface of the FRP laminate and the beam, leading to the development of localized interface cracks that, typically, propagate, under the effect of the load, to join the original flexural cracks and cause delamination of the FRP system. This type of FRP delamination is commonly termed intermediate crack (IC) debonding. In this paper the analytical models published in the literature are reviewed and it was found that these models do not correlate well with measured experimental results. This paper proposes an analytical model that characterizes the interface shear stress based on two distinct sources: (1) the change in the applied moments along the length of the member and (2) stress concentrations at the intermediate cracks. The proposed model is compared to an experimental database and shown to predict extremely well most of the test results reported by other researchers. A parametric study, performed using the proposed model, indicates that the model varies with several important variables that are not captured by most of the existing models.
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Acknowledgments
The writers would like to thank the generous contributions received from Paul Zia, Mina Dawood, Anthony Miller, and Catrina Walter. The North Carolina Department of Transportation funded much of this research and should be acknowledged. The writers also thank the helpful and thoughtful comments provided by the anonymous reviewers.
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Information
Published In
Journal of Composites for Construction
Volume 12 • Issue 2 • April 2008
Pages: 168 - 179
Copyright
© 2008 ASCE.
History
Received: Sep 6, 2006
Accepted: Jan 17, 2007
Published online: Apr 1, 2008
Published in print: Apr 2008
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