Effectiveness factor of the strut-and-tie model for reinforced concrete deep beams strengthened with CFRP sheet

Hanoon, Ammar N.; Jaafar, Mohd Saleh; Zaidee, Salah R. Al; Hejazi, Farzad; Aziz, Farah Nora Aznieta Abdul

doi:10.1016/j.jobe.2017.05.001

Cited by 27 publications

(12 citation statements)

References 10 publications

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“…Considerable advantages gained from retrofitting structural members by FRP. This was attained from the extremely good properties of FRP especially the high tensile strength; corrosion resistance is achievable and superior fatigue behavior [10][11][12]. Fiber reinforced polymer composites, when externally bonded onto concrete structures, effectively improve the structural performance in terms of load-carrying capacity, flexural stiffness, corrosion resistance and ductility [13].…”

Section: Introductionmentioning

confidence: 99%

Energy Absorption Evaluation of CFRP-Strengthened Two-Spans Reinforced Concrete Beams under Pure Torsion

Hanoon

Abdulhameed

et al. 2019

Civ Eng J

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For more than a decade, externally bonded carbon fiber reinforced polymer (CFRP) composites successfully utilized in retrofitting reinforced concrete structural elements. The function of CFRP reinforcement in increasing the ductility of reinforced concrete (RC) beam is essential in such members. Flexural and shear behaviors, ductility, and confinement were the main studied properties that used the CFRP as a strengthening material. However, limited attention has been paid to investigate the energy absorption of torsion strengthening of concrete members, especially two-span concrete beams. Hence, the target of this work is to investigate the effectiveness of CFRP-strengthening technique with regard to energy absorption of two-span RC beams subjected to pure torsion. The experimental program comprises the investigation of two groups; the first group comprises eight un-strengthened beam specimens, while the second group consists of eight strengthened beam specimens tested under torsional forces. The energy absorption capacity measured from the area under the curve of torque-angle of twist for tested beams. Two parameters were studied, the influence of concrete compressive strength and the angle of a twist. Experimental results indicated that all beams wrapped with CFRP sheet display superior torsional energy absorption capacity compared to the control specimens. The energy absorption may consider as a safety index for the torsional capacity of two-span RC beams under service loadings. Therefore, it is possible to avoid structural as well as material damages by understanding the concept of energy absorption that is one of the important experimental findings presented in this study.

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Section: Introductionmentioning

confidence: 99%

Energy Absorption Evaluation of CFRP-Strengthened Two-Spans Reinforced Concrete Beams under Pure Torsion

Hanoon

Abdulhameed

et al. 2019

Civ Eng J

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“…For this purpose, fiber-reinforced polymer (FRP) composites are applied to RC structures, which has been proven to have higher effectiveness in comparison with conventional methods of reinforcement, such as steel jackets. FRP has some advantages such as high flexibility, being a corrosion-resistant material, a high strength-to-weight ratio, and low thermal conductivity [7][8][9]. FRP-RC beams have been broadly employed as energy absorption designs, because they tend to deform higher than traditional RC beams, specifically due to higher energy absorption [10].…”

Section: Introductionmentioning

confidence: 99%

Torsional Strengthening of Reinforced Concrete Beams with Externally-Bonded Fibre Reinforced Polymer: An Energy Absorption Evaluation

et al. 2020

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The impacts of numerous important factors on the Energy Absorption (EA) of torsional Reinforced Concrete (RC) beams strengthened with external FRP is the main purpose and innovation of the current research. A total of 81 datasets were collected from previous studies, focused on the investigation of EA behaviour. The impact of nine different parameters on the Torsional EA of RC-beams was examined and evaluated, namely the concrete compressive strength (f’c), steel yield strength (fy), FRP thickness (tFRP), width-to-depth of the beam section (b/h), horizontal (ρh) and vertical (ρv) steel ratio, angle of twist (θu), ultimate torque (Tu), and FRP ultimate strength (fy-FRP). For the evaluation of the energy absorption capacity at different levels, Response Surface Methodology (RSM) was implemented in this study. Also, to fit the measured results, Quadratic and Line models were created. The results show that the RSM technique is a highly significant tool that can be applied not only to energy absorption-related problems examined in this research, but also to other engineering problems. An agreement is observed between Pareto and standardized charts with the literature showing that the EA capacity of the torsional FRP-RC beams is mostly affected by the concrete compressive strength, followed by the vertical reinforcement ratio. The newly suggested model in this article exhibits a satisfactory correlation co-efficient (R), of about 80%, with an adequate level of accuracy. The obtained results also reveal that the EA acts as a safety index for the FRP-strengthened RC beams exposed to torsional loadings to avoid sudden structural damage. Doi: 10.28991/cej-2020-SP(EMCE)-07 Full Text: PDF

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“…That said, to analyze the response of repaired beams analytically, and since the damage is localized at the end region of the beam, i.e., D-region, the use of the strut-and-tie model (STM) is warranted [10,11]. Many studies have shown the applications of STM to analyze the strengthening effect from FRP laminates [12][13][14][15][16][17][18]. However, STM has yet to be used to analyze the distressed end region of PC prestressed girder repaired by FRP laminate.…”

Section: Introductionmentioning

confidence: 99%

Experimental Testing and Strut-and-Tie Modeling of Full-Scale Precast Concrete Girders with FRP Repaired End Regions

Zhao

Andrawes

2020

Applied Sciences

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Bridges located in cold regions are susceptible to extreme deterioration due to harsh climate conditions. Distressing of girder’s end regions is among the most common damage types in these bridges. This work focuses on addressing this type of damage through the use of a fiber reinforced polymer (FRP) repair scheme. Three-point-bending tests are conducted on the control, damaged, mortar repair and carbon fiber reinforced polymer (CFRP) repair cases of bridge girders that are taken out of service. Test results are analyzed to investigate the effectiveness of FRP to repair precast concrete (PC) girders with damaged end regions. Furthermore, since the damage is mainly localized at girder’s end region where beam theory is invalid, the behavior of FRP repaired end region (D-region) is studied using the strut-and-tie method. Based on the test results, a strut-and-tie model (STM) is proposed to estimate the shear capacity of the girder with the FRP repaired end region. The outcome of the experimental work shows that the FRP laminate repair system is effective in recovering and improving the shear behavior of the girder including both peak force and ductility. The proposed STM can be used to predict the shear capacity of the PC girder with a similar damage pattern to the one considered in this study.

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Effectiveness factor of the strut-and-tie model for reinforced concrete deep beams strengthened with CFRP sheet

Cited by 27 publications

References 10 publications

Energy Absorption Evaluation of CFRP-Strengthened Two-Spans Reinforced Concrete Beams under Pure Torsion

Energy Absorption Evaluation of CFRP-Strengthened Two-Spans Reinforced Concrete Beams under Pure Torsion

Torsional Strengthening of Reinforced Concrete Beams with Externally-Bonded Fibre Reinforced Polymer: An Energy Absorption Evaluation

Experimental Testing and Strut-and-Tie Modeling of Full-Scale Precast Concrete Girders with FRP Repaired End Regions

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