View in EDS

Mechanistic Model for Concrete Cover Separation in FRP-Strengthened RC Beams: Anchorage Optimization through Controlled Crack Propagation.

Saved in:
Bibliographic Details
Title: Mechanistic Model for Concrete Cover Separation in FRP-Strengthened RC Beams: Anchorage Optimization through Controlled Crack Propagation.
Authors: Wang, Sai-sai1 (AUTHOR), Wen, Xiao-dong1 (AUTHOR) wenxiaodong@nbut.edu.cn, Gong, Wen-bo1 (AUTHOR)
Source: Journal of Bridge Engineering. Jun2026, Vol. 31 Issue 6, p1-11. 11p.
Subjects: Anchorage (Structural engineering), Crack propagation, Concrete fractures, Mechanical models, Concrete beams
Abstract: This study presents an innovative artificial tooth specimen incorporating bottom-embedded anchor rods for carbon fiber–reinforced polymer (CFRP)-strengthened concrete structures. Through systematic mechanical testing, we investigated the critical CFRP strain thresholds and horizontal crack propagation patterns in concrete covers, particularly analyzing shear-induced diagonal cracks and curvature variations. The experimental program evaluated the effects of anchor-rod embedment depth, spatial arrangement, and quantity on separation resistance of the concrete cover. Key findings reveal that pullout resistance increases proportionally with embedment depth, optimal anchor placement occurs within 0.2 L from the support (where L represents the specimen length), and excessive anchor density (>3 rods per 100 mm) induces stress concentration effects. Theoretical analysis using the concrete tooth model elucidates the separation mechanism and establishes a predictive mechanical model for cover detachment in anchored systems. The derived design equations demonstrate strong correlation with experimental data (R2 = 0.92), providing practical guidelines for seismic retrofit applications. Practical Applications: The anchorage system has been proven to efficiently prevent or delay debonding occurring. This near-surface-mounted technique is prone to concrete cover separation failure. It leads to obvious structural brittleness, and the material cannot fully utilize its properties. In contrast, the relevant research in this field is still in its initial stage, with insufficient understanding of the fundamental mechanisms and critical parameters. The influence of crack location, anchor rod position, and the thickness of th cover concrete was not considered. In this paper, an artificial tooth specimen was established to analyze the influence of different parameters (embedment depth, number of anchor rods, and spatial arrangement) on anchorage failure modes. The mechanism of concrete cover separation under different failure modes is revealed. The model for CFRP concrete cover separation anchored with implanted anchorage is established, and its accuracy is verified against the experiment results. It would provide a theoretical design approach for engineering design to limit cover concrete peeling. [ABSTRACT FROM AUTHOR]
Copyright of Journal of Bridge Engineering is the property of American Society of Civil Engineers and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
Database: Engineering Source
Description
Abstract:This study presents an innovative artificial tooth specimen incorporating bottom-embedded anchor rods for carbon fiber–reinforced polymer (CFRP)-strengthened concrete structures. Through systematic mechanical testing, we investigated the critical CFRP strain thresholds and horizontal crack propagation patterns in concrete covers, particularly analyzing shear-induced diagonal cracks and curvature variations. The experimental program evaluated the effects of anchor-rod embedment depth, spatial arrangement, and quantity on separation resistance of the concrete cover. Key findings reveal that pullout resistance increases proportionally with embedment depth, optimal anchor placement occurs within 0.2 L from the support (where L represents the specimen length), and excessive anchor density (>3 rods per 100 mm) induces stress concentration effects. Theoretical analysis using the concrete tooth model elucidates the separation mechanism and establishes a predictive mechanical model for cover detachment in anchored systems. The derived design equations demonstrate strong correlation with experimental data (R2 = 0.92), providing practical guidelines for seismic retrofit applications. Practical Applications: The anchorage system has been proven to efficiently prevent or delay debonding occurring. This near-surface-mounted technique is prone to concrete cover separation failure. It leads to obvious structural brittleness, and the material cannot fully utilize its properties. In contrast, the relevant research in this field is still in its initial stage, with insufficient understanding of the fundamental mechanisms and critical parameters. The influence of crack location, anchor rod position, and the thickness of th cover concrete was not considered. In this paper, an artificial tooth specimen was established to analyze the influence of different parameters (embedment depth, number of anchor rods, and spatial arrangement) on anchorage failure modes. The mechanism of concrete cover separation under different failure modes is revealed. The model for CFRP concrete cover separation anchored with implanted anchorage is established, and its accuracy is verified against the experiment results. It would provide a theoretical design approach for engineering design to limit cover concrete peeling. [ABSTRACT FROM AUTHOR]
ISSN:10840702
DOI:10.1061/JBENF2.BEENG-7816