Debonding-Related Strain Limits for Externally Bonded FRP Sheets in Flexurally Strengthened Reinforced Concrete Beams

Li, Guibing; Zhang, Aihui; Guo, Yugang

doi:10.2174/1874149520130517002

Cited by 10 publications

(7 citation statements)

References 5 publications

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“…Kang et al [10] conducted a detailed review of previous research programs that were conducted by past researches in relation to debonding failure of FRP attached externally to the concrete surface. Li et al [16] conducted a series of experimental tests on reinforced concrete beams that were strengthened with externally bonded CFRP sheets in flexure. They investigated debonding initiation and the allowable tensile strain of FRP sheets in flexurally-strengthened RC beams in comparison to different design code provisions.…”

Section: Literature Reviewmentioning

confidence: 99%

“…Their research work was based on a database, which was collected from recent literature and mainly focused on the basic codes for reinforced concrete structures (without strengthening) and current models for FRP structures strengthened in shear. Li et al investigated debonding initiation and tensile strain of FRP laminates adhered externally to concrete beam surfaces [16]. Experimental testing was carried out and the allowable tensile strain in FRP sheets proposed by prevalent code provisions was assessed.…”

Section: Literature Reviewmentioning

confidence: 99%

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Cracking Behavior of RC Beams Strengthened with Different Amounts and Layouts of CFRP

et al. 2019

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The bending and shear behavior of RC beams strengthened with Carbon Fiber-Reinforced Polymers (CFRP) is the primary objective of this paper, which is focused on the failure mechanisms and on the moment-curvature response prior-to, and post, strengthening with different amounts and layouts of the CFRP reinforcement. Seven reinforced concrete beams were tested in 4-point bending, one without any CFRP reinforcement (control beam, Specimen C1), four with the same amount of CFRP in flexure but with different layouts of the reinforcement for shear (Specimens B1–B4), and two with extra reinforcement in bending, with and without reinforcement in shear (Specimens B6 and B5, respectively). During each test, the load and the mid-span deflection were monitored, as well as the crack pattern. The experimental results indicate that: (a) increasing the CFRP reinforcement above certain levels does not necessarily increase the bearing capacity; (b) the structural performance can be optimized through an appropriate combination of CFRP flexural and shear reinforcement; and (c) bond properties at the concrete–CFRP interface play a vital role, as the failure is very often triggered by the debonding of the CFRP strips. The experimental values were also verified analytically and a close agreement between the analytical and experimental values was achieved.

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Section: Literature Reviewmentioning

confidence: 99%

Section: Literature Reviewmentioning

confidence: 99%

Cracking Behavior of RC Beams Strengthened with Different Amounts and Layouts of CFRP

et al. 2019

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“…They presented the results of their analytical and experimental study in the performance of reinforced concrete beams strengthened in shear with FRP composites and internally reinforced with conventional steel stirrups. Li et al performed experimental tests on concrete beams which were strengthened with externally bonded CFRP sheets to investigate debonding initiation and tensile strain of FRP laminates, and investigated the allowable tensile strain of FRP-strengthened RC beams in comparison to design code provisions [29]. Hasnat et al enhanced the debonding strain limit for CFRP-strengthened RC Beams by using U-Clamps and tried to resist premature cover debonding failure [30].…”

Section: Literature Reviewmentioning

confidence: 99%

Flexural and Shear Strain Characteristics of Carbon Fiber Reinforced Polymer Composite Adhered to a Concrete Surface

Qureshi

Saleem

2018

Materials

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The use of Fiber Reinforced Polymer (FRP) composites for strengthening concrete structures has gained a lot of popularity in the past couple of decades. The major issue in the retrofitting of concrete structures with FRP is the accurate evaluation of flexural and shear strains of polymer composites at the bonding interface of epoxy and concrete. To address it, a comprehensive experimental study was planned and carbon fiber reinforced polymer (CFRP) composite was applied on the concrete surface with the help of adhesives. CFRP was used as an external mounted flexural and shear reinforcement to strengthen the beams. Flexural load tests were performed on a group of eight reinforced concrete beams. These beams were strengthened in flexural and shear by different reinforcement ratios of CFRP. The strain gauges were applied on the surface of concrete and CFRP strips to assess the strain of both CFRP and concrete under flexural and shear stresses. The resulting test data is presented in the form of load–deformation and strain values. It was found that the values of strains transferred to the FRP through the concrete are highly dependent on the surface tensile properties of concrete and debonding strength of the adhesive. The test results clearly indicated that the strength increment in flexural members is highly dependent on strain values of the CFRP.

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“…The structural behavior of flexural members with bonded FRPs as external reinforcement has been extensively investigated [7][8][9][10][11][12]. In all these studies, the lack of an effective anchorage of the composite plate reinforcing the RC member results in loss of the flexural design capacity of the member.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Structural Response of Reinforced Concrete Beams Strengthened with Anchored FRPs

Demakos¹,

Repapis²,

Drivas³

2013

TOBCTJ

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Abstract:The beneficial effect of a composite material anchorage system (CMAS) upon the ductility and load capacity of reinforced concrete (RC) beams strengthened either with glass (GFRP) or carbon (CFRP) fabrics was investigated. The anchorage system consisted of U-shaped GFRP or CFRP strip (U-strip) at end of FRP. The U-strips were bonded around the beam section and further anchored by two tufts of glass fibres, each of them embedded at the opposite beam face and specifically in the region of compression zone of the beam web. Experimental evaluations in simply supported lightly reinforced concrete (RC) beams strengthened with one GFRP or a CFRP sheet anchored at its ends by the composite anchorage have shown that their bending capacity has increased by 8% and 17%, respectively, in relation to the capacity attained in similar RC strengthened beams without anchorage. On the other hand, their ductility was improved by an amount of 94% and 37%, respectively. ANSYS finite element program was also used to numerically verify the response of strengthened RC beams obtained experimentally. The numerical results obtained are in good agreement with the experimental, thus, the calibrated model could now be used to extend the experimental results at lower cost.

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Debonding-Related Strain Limits for Externally Bonded FRP Sheets in Flexurally Strengthened Reinforced Concrete Beams

Cited by 10 publications

References 5 publications

Cracking Behavior of RC Beams Strengthened with Different Amounts and Layouts of CFRP

Cracking Behavior of RC Beams Strengthened with Different Amounts and Layouts of CFRP

Flexural and Shear Strain Characteristics of Carbon Fiber Reinforced Polymer Composite Adhered to a Concrete Surface

Investigation of Structural Response of Reinforced Concrete Beams Strengthened with Anchored FRPs

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