Contribution of Longitudinal NSM-CFRP Bars on the Shear Strength of RC Beams with Varying Depths and Concrete Strengths
Publication: Journal of Composites for Construction
Volume 26, Issue 3
Abstract
To assess experimentally the effect of flexural near surface mounted (NSM) carbon fiber-reinforced polymer (CFRP) bars mounted on the sides of beams on the shear strength of reinforced concrete (RC) beams, 18 shear-deficient RC beams were built, strengthened with flexural NSM-CFRP bars, and tested under three-point bending until failure. The variables of the experimental program included the beam depth, the concrete compressive strength, and the flexural fiber-reinforced polymer (FRP) reinforcement ratio. It was observed that the strengthened beams exhibited up to 35% increase in shear capacity over the control beams. It was also observed that the increase in shear strength provided by concrete after strengthening was higher for beams with normal strength concrete when compared to those with higher strength concrete. The results have also revealed that the percent change in shear strength provided by concrete for the strengthened beams decreased with the increase in beam depth. Experimental data from this study showed that current standards become unconservative for beams with large depths. Five different beam shear strength models found in the literature were utilized to predict the shear strength of the tested beams. The models that exhibited the closest agreement with the experimental data were those of the University of Houston and the second order simplified modified compression field theory. It was concluded that flexural longitudinal NSM bars are a viable solution to enhance the shear strength of RC beams and that the shear strength provided by concrete can be accurately quantified using published models.
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Acknowledgments
The authors gratefully acknowledge the support of the American University of Sharjah for sponsoring this research project. The authors also thank and acknowledge Structural Technologies for installing and providing the NSM bars and epoxy adhesives.
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Journal of Composites for Construction
Volume 26 • Issue 3 • June 2022
Copyright
© 2022 American Society of Civil Engineers.
History
Received: Apr 28, 2021
Accepted: Jan 13, 2022
Published online: Mar 14, 2022
Published in print: Jun 1, 2022
Discussion open until: Aug 14, 2022
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Cited by
- Mand Kamal Askar, Ali Falyeh Hassan, Yaman S.S. Al-Kamaki, Flexural and shear strengthening of reinforced concrete beams using FRP composites: A state of the art, Case Studies in Construction Materials, 10.1016/j.cscm.2022.e01189, 17, (e01189), (2022).