Experimental Study on Flexural Cracking and Deformation of Reinforced-Concrete Beams Strengthened with NSM FRP Reinforcement
Publication: Journal of Composites for Construction
Volume 27, Issue 2
Abstract
A near-surface-mounted (NSM) technique using fiber-reinforced polymer (FRP) reinforcement increases the load-bearing capacity and stiffness of reinforced-concrete (RC) beams and delays the yielding moment. In those cases, the verification of serviceability limit states becomes necessary to guarantee functionality and protection of steel reinforcement. At present, there is a lack of provisions for the crack width prediction, mainly because of the scarceness of experimental data. This work presents the results of an experimental program aiming at studying the effect of different NSM reinforcement arrangements on the midspan deflection, crack spacing, and crack width of NSM FRP RC beams. One RC beam and 11 NSM FRP RC beams were tested under a four-point bending configuration up to failure. Carbon- and glass-FRP rods were used. It was found that NSM FRP reinforcement provides an effective reduction in deflection, crack width, and spacing. Larger crack formation phases were observed in all strengthened specimens. Moreover, crack width decreases with the increase of the NSM FRP reinforcement ratio. Finally, cracks at the bottom of the beam are around 11%–25% wider than at the height of the steel internal reinforcement.
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Acknowledgments
This research was supported by the Spanish Ministry of Science, Innovation, and Universities (project BIA2017-84975-C2-2-P), and the Generalitat de Catalunya (Grant Numbers 2019FIB-00054 and 2020FISDU-00476). The authors also wish to acknowledge the support of S&P Clever Reinforcement Ibérica Lda., SIKA and Schoek for supplying the epoxy resin and FRP laminates and bars used in this study.
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Published In
Journal of Composites for Construction
Volume 27 • Issue 2 • April 2023
Copyright
© 2023 American Society of Civil Engineers.
History
Received: Jan 26, 2022
Accepted: Nov 22, 2022
Published online: Jan 18, 2023
Published in print: Apr 1, 2023
Discussion open until: Jun 18, 2023
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