Effect of GFRP Reinforcement Ratio on the Strength and Effective Stiffness of High-Strength Concrete Columns: Experimental and Analytical Study
Publication: Journal of Composites for Construction
Volume 24, Issue 5
Abstract
This paper reports the axial–flexural test results for 12 high-strength concrete (HSC) columns reinforced with glass fiber-reinforced polymer (GFRP) rebars to evaluate the implication of using HSC. The parameters were the applied eccentricity, the longitudinal GFRP reinforcement ratio, and concrete compressive strength and investigate their influence on the load-carrying capacity, deflection, ductility, strains in the concrete and reinforcement, failure modes, and flexural stiffness. All the columns failed in a compression failure mode due to concrete crushing. The GFRP bars developed higher tensile strains in the HSC due to the axial–flexural load compared to columns made with normal-strength concrete (NSC). A minimum reinforcement ratio of 1% in the case of HSC proved practical. Increasing the reinforcement ratio to 2.5% improved the postpeak behavior and yielded a second peak for specimens tested at eccentricities corresponding to 30%, 40%, and 60% of the cross-sectional depth. This study integrated the results to develop an analytical model able to establish moment–curvature and effective-stiffness relationships. The results were also evaluated for the tested specimens and compared to the theoretical expressions used for NSC.
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Acknowledgments
The authors would like to express their special thanks and gratitude to the Natural Science and Engineering Research Council of Canada (NSERC), the NSERC Industrial Research Chair in FRP Reinforcement for Concrete Infrastructure, the Tier-1 Canada Research Chair in Composite Materials for Civil Structures, and the Fonds de la recherche du Quebec-Nature et Technologie (FRQ-NT) for their financial support. The authors would like to thank TUF-BAR Canada for providing the GFRP reinforcement and the technical staff of the Structural and Materials Lab in the Department of Civil Engineering at the University of Sherbrooke.
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© 2020 American Society of Civil Engineers.
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Received: Jun 4, 2019
Accepted: May 28, 2020
Published online: Jul 30, 2020
Published in print: Oct 1, 2020
Discussion open until: Dec 30, 2020
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