Experimental and Numerical Study on RC Beams Strengthened by NSM Using CFRP Reinforcements

Abdesselam, A.; Merdas, Abdelghani; Fiorio, Bruno; Chikh, Nasr‐Eddine

doi:10.3311/ppci.21309

Cited by 3 publications

(2 citation statements)

References 30 publications

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“…Chen et al investigated the U-wrap CFRP technique [9,13,14] and found that the bond length of the CFRP in this technique was constrained by the crosssectional dimensions of the concrete structure [15,16]. In addition, Ammar et al introduced near-surface-mounted (NSM) technology to shear-strengthening research [17,18], which can effectively enhance the shear-carrying capacity and deformation capacity when structures fail [19,20]. However, when the CFRP ratio is too high, it may cause the failure mode of reinforced beams to change to concrete cover delamination, resulting in the premature failure of the specimens [21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on Shear Performance of Concrete Beams Reinforced with Externally Unbonded Prestressed CFRP Tendons

Qi,

Jiang,

Wang

et al. 2024

Fibers

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To investigate the reinforcing effect of externally prestressed carbon-fiber-reinforced polymer (CFRP) tendons on the shear performance of reinforced concrete beams, a set of model tests was designed. Static load comparative tests were conducted on one original beam and four reinforced beams to experimentally investigate the impacts of the prestress level and damage in the shear zone on the shear reinforcement effect and analyze the reinforcement mechanism of CFRP tendons. The results show that in the beams reinforced with CFRP, the CFRP tendons could work collaboratively with the stirrups to reduce the strain on the stirrups; the increasing rate in the yield load was 28–70%. After the stirrups yielded, the CFRP tendons did not yet reach their ultimate tensile strength and could still withstand increased shear forces, resulting in an increasing rate of the ultimate load for the reinforced beams with a CFRP content of 56–78%. The enhancements in both the yield load and the ultimate load were positively correlated with the level of prestress in the CFRP tendons. This reinforcement technique efficiently restricts the growth and delays the first appearance of diagonal cracks. The prestress can close the pre-existing diagonal cracks and provide a reserve of shear capacity for the beams. The initial damage in the shear zone decreases the initial shear stiffness and increases the width of the initial diagonal cracks. However, this effect gradually diminishes as the load increases and does not significantly impact the shear capacity. Prestressing can significantly improve the strength utilization rate of the CFRP reinforcement when the reinforced beams fail. The deformation of the CFRP tendon is directly related to the shear deformation. By combining this relationship with the truss–arch model, the shear capacity for the reinforced beam can be predicted. The predicted results exhibit an error of less than 10% when compared to the test results, offering valuable design guidance for reinforced engineering composites.

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Section: Introductionmentioning

confidence: 99%

Experimental Study on Shear Performance of Concrete Beams Reinforced with Externally Unbonded Prestressed CFRP Tendons

Qi,

Jiang,

Wang

et al. 2024

Fibers

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“…When columns exposed to earthquake effects are wrapped with fiber reinforced polymer, although there is no significant increase in lateral rigidity and lateral load capacity, there is an improvement in displacement capacities [6]. In recent years, many studies have been carried out on the methods of full carbon fiber reinforced polymer cladding on reinforced concrete columns and carbon fiber reinforced polymer cladding by partial wrapping [7][8][9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Effect of Wrapping Thickness and Type on Reinforced Bridge Piers: A Numerical Study

Gürbüz,

Ustabaş,

Kurt

et al. 2024

Period. Polytech. Civil Eng.

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This research paper investigates the impact of wrapping thickness and type on reinforced bridge piers through a numerical study. The Incesu bridge, located in the Ardanuç district of Artvin province, was selected as the case study, as it was completed with low concrete strength. Initially, the bridge was examined, revealing that the piers were inadequate against dynamic, dead, pedestrian, and covering loads. The study concentrated on employing carbon fiber reinforced polymer to reinforce the bridge piers. Various models were wrapped with carbon fiber reinforced polymer in full-length, half-length, and one-meter intervals. In the analysis, it is assumed that the wraps are linked to each other in both principal directions and not detached from one another. Along with the analyses conducted, stress and strain values are presented separately. It was observed that the wrapping effect obtained in small-sized elements in literature could not be obtained in large-sized elements. As the concrete quality improves, the influence of wrapping thickness diminishes. Moreover, the effects of full-length and half-length wrapping are very close to each other, suggesting that half-length wrapping of bridge piers is sufficient. The authors believe that the obtained analysis results will prove beneficial in achieving economic advantages in retrofitting projects within the construction sector.

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Experimental analysis of the bond-slip characteristics between CFRP and natural stone masonry units

Mohamed,

Abdelghani,

Taha Hocine

2024

WJE

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Purpose Although the reinforcement of concrete and brick masonry with fiber-reinforced polymer (FRP) has been extensively researched, its application and impact on natural stone, especially in historic preservation, have received less attention. This study aims to examine the bond-slip characteristics of carbon fiber-reinforced polymer (CFRP) with two types of natural stone masonry, aiming to enhance their effectiveness in reinforcing historic structures. The stones studied include one from the Chouf-Lekdad region (A) and another from a historic structure in Sétif City (B). Both stones were strengthened using CFRP and carbon fiber fabric (CFF) through near-surface mount (NSM) and external bonding (EBR) techniques. Design/methodology/approach The interaction was assessed during the pull-out test by analyzing the stress transfer mechanisms, adhesion and deformation. This study also examines the effects of the following parameters on the bond between CFRP and stone: type of stone (A and B), type of reinforcement (plat CFRP and CFF), various notch shapes and sizes (bp, tp and Lb), and reinforcement techniques (NSM and EBR). Findings This study demonstrated the practicality and effectiveness of enhancing natural stone masonry of old buildings by integrating NSM and EBR techniques with CFRP. With a bond length of 30 mm, the pull-out force correlates with the strength of the stone. This indicates the importance of stone strength in obtaining better adhesion. The CFF–resin interface is more cohesive than the CFRP plate–resin interface because the resin penetrates the flexible CFF strip, ensuring better adhesion. In contrast, the CFRP plate interface is rigid and smooth. The results suggest that natural stone–CFRP adhesion is more effective than CFRP bonded to concrete and brick masonry due to the stone's strong resistance. Originality/value This experimental investigation provides new study into the bond-slip behavior of CFRP-reinforced natural stone masonry, filling the gap in existing research. The findings offer useful direction for creating FRP strengthening solutions that are specifically adapted to the properties of natural stone used in historic constructions. This study helps to improve preservation procedures by guiding the selection of reinforcing techniques, such as NSM versus EBR, and finding ideal bond lengths. This work's novelty stems from its ability to improve the structural integrity of culturally significant buildings while preserving their historical authenticity.

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Experimental and Numerical Study on RC Beams Strengthened by NSM Using CFRP Reinforcements

Cited by 3 publications

References 30 publications

Experimental Study on Shear Performance of Concrete Beams Reinforced with Externally Unbonded Prestressed CFRP Tendons

Experimental Study on Shear Performance of Concrete Beams Reinforced with Externally Unbonded Prestressed CFRP Tendons

Effect of Wrapping Thickness and Type on Reinforced Bridge Piers: A Numerical Study

Experimental analysis of the bond-slip characteristics between CFRP and natural stone masonry units

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