Bond Between EBR FRP and Concrete

Mazzotti, Claudio; Bilotta, Antonio; Carloni, Christian; Ceroni, Francesca; D’Antino, Tommaso; Nigro, Emidio; Pellegrino, Carlo

doi:10.1007/978-94-017-7336-2_3

Cited by 9 publications

(7 citation statements)

References 82 publications

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“…In the system FRP/adhesive/concrete, debonding may take place within the concrete (cohesive failure), the adhesive (cohesive failure), the laminate (delamination failure), or in the interfaces between these materials (adhesion failure). If a proper application of the strengthening system is carried out, the weakest part of the system is the concrete layer near the interface with the adhesive as the tensile strength of the concrete is usually much lower than the adhesive strength [ 9 ]. Considering the origin of the debonding, failure modes can be classified as intermediate crack debonding (ICD), starting at an intermediate section of the beam due to flexural (or flexural-shear) cracks and propagating to the support, and end debonding (ED), which occurs at the curtailment region of the FRP reinforcement.…”

Section: Introductionmentioning

confidence: 99%

“…Considering the origin of the debonding, failure modes can be classified as intermediate crack debonding (ICD), starting at an intermediate section of the beam due to flexural (or flexural-shear) cracks and propagating to the support, and end debonding (ED), which occurs at the curtailment region of the FRP reinforcement. As observed from experiments in the literature, ICD is usually the governing failure mode in flexural applications [ 9 , 10 ].…”

Section: Introductionmentioning

confidence: 99%

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Assessment of fib Bulletin 90 Design Provisions for Intermediate Crack Debonding in Flexural Concrete Elements Strengthened with Externally Bonded FRP

Barris

Jahani

et al. 2023

Polymers

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With the assessment of intermediate crack debonding (ICD) being a subject of main importance in the design of reinforced concrete (RC) beams strengthened in flexure with externally bonded fibre-reinforced polymer (FRP), several approaches to predict the debonding loads have been developed in recent decades considering different models and strategies. This study presents an analysis of formulations with different levels of approximation collected in the fib Bulletin 90 regarding this failure mode, comparing the theoretical predictions with experimental results. The carried-out experiments consisted of three RC beams strengthened with carbon FRP (CFRP) tested under a four-point bending configuration with different concrete strengths and internal steel reinforcement ratios. With failure after steel yielding, higher concrete strength, as well as a higher reinforcement ratio, lead to a higher bending capacity. In addition, the performance of the models is assessed through the experimental-to-predicted failure load ratios from an experimental database of 65 RC beams strengthened with CFRP gathered from the literature. The results of the comparative study show that the intermediate crack debonding failure mode is well predicted by all models with a mean experimental-to-predicted failure load ratio between 0.96 and 1.10 in beams tested under three- or four-point bending configurations.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Assessment of fib Bulletin 90 Design Provisions for Intermediate Crack Debonding in Flexural Concrete Elements Strengthened with Externally Bonded FRP

Barris

Jahani

et al. 2023

Polymers

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“…The CFRP jacket provides the RC columns with passive confinement and is stressed only when an additional axial load is applied to a column that causes dilation. The degree of confinement and the overall strength enhancement of confined concrete is influenced by several factors: fiber modulus, fiber thickness, fiber rupture strain, column size, and column shape (circular, square, or rectangular) [5]. In addition to the FRP method, a steel jacket can improve the load-carrying capacity of the RC column.…”

Section: Introductionmentioning

confidence: 99%

A Comparative Study on Behavior of RC Columns Strengthened by CFRP and Steel Jacket

Ibraheem

Al-Zuhairi

2021

E3S Web Conf.

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This paper studies the behavior of axially loaded RC columns which are confined with carbon fiber reinforced polymers’ sheet (CFRP) and steel jackets (SJ). The study is based on twelve axially loaded RC columns tested up to failure. It is divided into three schemes based on its strengthening type; each scheme has four columns. The main parameters in this study were the compressive strength of the concrete and steel reinforcement ratio. Furthermore, the results of the experimental test showed a substantial enhancement in the column's load-carrying capacity. When compared to the original columns, the CFRP sheet had a significant effect on improving the ductility of the column by increasing the axial deformation by about 59.2 to 95.7%. On the other hand, the SJ contributed mostly to the column load-carrying capacity, which increased the capacity of RC concrete from 75 to 107%; because of its composite action comparing with the CFRP sheet action in which unidirectional lateral confinement is provided. Both methods produced completely different failure modes. The columns strengthened with CFRP sheet failed by rupture occurring in the sheet fibers. The strengthened with SJ failed due to the buckling that occurred in the steel angles due to the direct contact with the head of the column, and crushing in the concrete has occurred.

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“…A few years later, other techniques emerged such as the near-surface mounted (NSM), where the FRP laminate or bar is inserted onto a groove previously cut in the concrete cover. According to the literature, when FRP are used as reinforcement material, bond behavior between this and concrete substrate is generally a critical issue for both EBR [8,9,10,11,12,13,14,15,16,17,18,19] and NSM techniques [13,16,20,21,22,23,24] that directly influence the effectiveness of the structural reinforcement. The strengthening performance of these techniques depends significantly on the resistance of the concrete cover, which is normally the most degraded concrete region in the structure and the concrete surface condition.…”

Section: Introductionmentioning

confidence: 99%

“…The present work focuses on the bond behavior characterization between EBR CFRP system reinforcement and the concrete surface. As many researchers verified in their experimental works when this technique was applied, the bond strength depends on several factors, including mechanical and physical properties of concrete, composite material and epoxy adhesive which prevent the fully FRP tensile strength to be attained due to the premature debonding failure that typically occurs [12,13,15]. Moreover, it is well known that the concrete surface preparation and bonding technique are crucial tasks for adequate installation of an EBR FRP system to delay the brittle debonding failure.…”

Section: Introductionmentioning

confidence: 99%

Influence of Surface Preparation Method on the Bond Behavior of Externally Bonded CFRP Reinforcements in Concrete

et al. 2019

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In last decades significant investigation has been carried out in order to predict the bond strength of externally bonded reinforcement (EBR) systems with carbon fiber reinforced polymer (CFRP) materials in concrete and, as consequence of that, many analytical expressions can be found in the literature, including in standards. However, these expressions do not account for the influence of several parameters on bond behavior such as the type of surface preparation which is a mandatory and critical task in the strengthening application. The present work gives contributions to reduce this lack of knowledge. For this purpose, an experimental program composed of single-lap shear tests was carried out, the main parameters studied being: (i) the type of concrete surface preparation (i.e., grinding and sandblasting) and (ii) the bond length. Prior to the application of the EBR CFRP system, the roughness level provided by the different methods of surface preparation was characterized by a laser sensor. Test results revealed that sandblasting concrete surface preparation yielded higher values, in terms of maximum shear force and fracture energy. Finally, existing expressions in standards were upgraded in order to account for the concrete surface roughness level in the estimation of the bond strength.

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Bond Between EBR FRP and Concrete

Cited by 9 publications

References 82 publications

Assessment of fib Bulletin 90 Design Provisions for Intermediate Crack Debonding in Flexural Concrete Elements Strengthened with Externally Bonded FRP

Assessment of fib Bulletin 90 Design Provisions for Intermediate Crack Debonding in Flexural Concrete Elements Strengthened with Externally Bonded FRP

A Comparative Study on Behavior of RC Columns Strengthened by CFRP and Steel Jacket

Influence of Surface Preparation Method on the Bond Behavior of Externally Bonded CFRP Reinforcements in Concrete

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