Shear Capacity of Reinforced Concrete T-Beams Retrofit with Externally Bonded CFRP Fabric: A New Perspective
Publication: Journal of Structural Engineering
Volume 146, Issue 12
Abstract
Unanchored U-wrapped externally bonded carbon-fiber-reinforced polymer (CFRP) fabrics are widely used to increase the design shear strength of existing reinforced concrete slab-on-beam structures, but current design models do not accurately predict the degree of enhancement. Experimental investigations further indicate that some T-beams retrofit with externally bonded CFRP fabric fail at lower shear loads than nominally identical nonretrofit reference counterparts, suggesting a negative experimental CFRP contribution. This work finds a new application for the upper-bound theorem of plasticity in analyzing the problem of U-wrapped externally bonded CFRP-retrofit beam behavior. The study provides insight into the poor historical prediction of the CFRP contribution, and demonstrates the limitations of a widely used experimental approach to determining this contribution. The analysis suggests a new way of thinking about the behavior of slab-on-beam structures retrofit with unanchored U-wrapped externally bonded CFRP. The upper-bound plastic analysis provides better predictions of retrofit shear capacity than some widely used design models, indicating that this approach can lead to better design of retrofit interventions in future. This work proposes a new design limit on enhancement that can reduce the likelihood of unsafe design in practice.
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Data Availability Statement
All data, models, and code generated or used during the study appear in the published article. The analysis presented in this publication is underpinned by published experimental data whose original sources are indicated in the references.
Acknowledgments
The authors gratefully acknowledge the support of the UK Engineering and Physical Sciences Research Council (EPSRC) through Grant No. EP/I018972/1.
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Published In
Journal of Structural Engineering
Volume 146 • Issue 12 • December 2020
Copyright
© 2020 American Society of Civil Engineers.
History
Received: Sep 23, 2019
Accepted: Jun 11, 2020
Published online: Sep 16, 2020
Published in print: Dec 1, 2020
Discussion open until: Feb 16, 2021
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