Shear Strength Model for FRP-Strengthened RC Beams with Adverse FRP-Steel Interaction
Publication: Journal of Composites for Construction
Volume 17, Issue 1
Abstract
RC beams shear strengthened with externally bonded fiber-reinforced polymer (FRP) U strips or side strips usually fail owing to debonding of the bonded FRP shear reinforcement. Because such debonding usually occurs in a brittle manner at relatively small shear crack widths, some of the internal steel stirrups intersected by the critical shear crack may not have reached yielding at beam shear failure. Consequently, the yield stress of internal steel stirrups in such a strengthened RC beam cannot be fully utilized. This adverse shear interaction between the internal steel shear reinforcement and the external FRP shear reinforcement may significantly reduce the benefit of the shear-strengthening FRP but has not been considered explicitly by any of the shear strength models in the existing design guidelines. This paper presents a new shear strength model considering this adverse shear interaction through the introduction of a shear interaction factor. A comprehensive evaluation of the proposed model, as well as three other shear strength models, is conducted using a large test database. It is shown that the proposed shear strength model performs the best among the models compared, and the performance of the other shear strength models can be significantly improved by including the proposed shear interaction factor. Finally, a design recommendation is presented.
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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 (Project No. PolyU 5151/03E), the Niche Area Funding Scheme of The Hong Kong Polytechnic University, and the National Natural Science Foundation of China (Projects No. 51108097 and No. 10802023). They would also like to acknowledge the support from the Scottish Funding Council for the Joint Research Institute between the University of Edinburgh and Heriot-Watt University, which forms part of the Edinburgh Research Partnership in Engineering and Mathematics (ERPem). The authors are also grateful to the following researchers for their valuable help in establishing the database presented in this paper: Dr. J. A. O. Barros, Dr. L. De Lorenzis, Dr. A. J. Beber, Dr. G. Kim, Dr. H. Oh, Dr. G. Gas, and Professor Z. F. Chen.
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Information
Published In
Journal of Composites for Construction
Volume 17 • Issue 1 • February 2013
Pages: 50 - 66
Copyright
© 2013 American Society of Civil Engineers.
History
Received: Dec 19, 2011
Accepted: May 24, 2012
Published online: May 28, 2012
Published in print: Feb 1, 2013
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