Strengthening of deficient reinforced concrete columns subjected to concentric and eccentric loads

El-Kashif, Khaled F.; Hazem, Abdel-Rahman; Rozik, Mohamed Ahmed; Abdalla, Hany

doi:10.1177/1369433219895358

Cited by 6 publications

(4 citation statements)

References 23 publications

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“…This behavior can be because of the constraint imposed by the loading plates at the two ends of the specimens causing the cracks to start at the top and bottom of the columns. The same behavior of cracking was reported in previous research [9,38,39]. As the loading increased, the width of the cracks increased, and new cracks started to develop propagating towards the mid height of the specimen.…”

Section: Modes Of Failure and Crack Patternssupporting

confidence: 85%

Strengthening of reinforced concrete short columns using ferrocement under axial loading

Mabrouk

Awad²,

Abdelkader³

et al. 2022

Journal of Engineering Research

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Reinforced concrete columns play an important role in distributing loads from slabs and beams to foundations. As a result of time, fatigue, or other factors, the reinforced columns are exposed to deterioration, and it is required to strengthen or repair these columns. Ferrocement jacketing can be considered as an easy and cheap method which has a significant effect on strengthening members. The main objective of this research is to study the effect of strengthening short columns using ferrocement jackets. Fourteen short square columns having the same dimensions were tested under axial loading. One column was designed as a control specimen and the other thirteen specimens were strengthened with ferrocement while changing the type and number of layers. It was found that using ferrocement as strengthening method increased the strength of columns in average from 11 to 40 %. Following that, a finite element analysis was conducted using the tested column specimens to further assess the usage of ferrocement jackets for strengthening concrete columns. A modified equation was proposed to calculate the capacity of short square columns strengthened using ferrocement jackets. Comparison with experimental data showed that the proposed equation gives good correlation compared to the experimental data.

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Section: Modes Of Failure and Crack Patternssupporting

confidence: 85%

Strengthening of reinforced concrete short columns using ferrocement under axial loading

Mabrouk

Awad²,

Abdelkader³

et al. 2022

Journal of Engineering Research

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“…The results showed that all of the strengthening techniques improved the ultimate loads. Also, CFRP wrapping experienced high ductility for both cases of loading [9]. Naji et al (2021) reviewed the rehabilitation and strengthening techniques for reinforced concrete columns.…”

Section: Introductionmentioning

confidence: 99%

Structural Behavior of Hybrid Reinforced Concrete Short Columns Under Uniaxial Load

Hassoon

Mosheer

2023

IJAEFEA

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Columns are essential part of several civil engineering applications that relocate the weight of the superstructure and the other loads to the soil. Usually, columns are subjected to eccentric compressive loads. Sometimes, it is required to increase the cross-sectional area of columns to gain additional load capacity. This paper investigates the behavior of reinforced concrete columns under uniaxial loading. Five specimens of 0.2 × 0.2 × 1 m were fabricated to study the effect of type of concrete and near surface mounted NSM strengthening technique on the structural behavior of the columns. All columns were tested under uniaxial loads of 50 mm offset with simply supported ends. The presented strengthening techniques are flexible and effective. The experimental results showed that using of steel fiber concrete SFC of 1% volume fraction raised the ultimate load by 200% while increasing of concrete strength by 42.1% achieved just 36.4% additional load capacity. Also, strengthening of columns using NSM steel and carbon fiber reinforced polymer bars increased the load carrying capacity by 54.5 to 136.4%. Furthermore, the stiffness criteria increased by 105.3, 29.3, and 90% for the specimens with higher compressive strength, SFC, and strengthened with NSM steel bars owing to the additional stiffness provided. However, the brittle weakness nature of FRP composites in compression decreased the stiffness criteria by 14.6%.

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“…This improvement is ascribed to the high strength-to-weight ratio, high corrosion resistance, easier application in narrowed spaces, lessening labor costs, and easiness in site handling for FRP composites (Ali et al, 2020; Aslam et al, 2021; El Ouni and Raza, 2021; Ilki et al, 2008; Pour et al, 2019; Raza et al 2019, 2021a, 2021b, 2021c; Raza and Rafique, 2020; Rafique et al, 2021). The FRP composites are advanced materials for the strengthening and stiffening of the structural elements (Ali and Forth, 2021; El-Kashif et al, 2020; Huang et al, 2020; İşleyen et al, 2021; Tu et al, 2019; Wang et al, 2015; Wu et al, 2006; Zhang et al, 2020; Li and Jiao, 2021; Zhu et al, 2005; Zeng et al, 2021). In this context, several studies were performed to investigate the axial compression performance of CFRP-wrapped concrete in a circular section (Al-Nimry and Neqresh, 2019; Cui and Sheikh, 2010; Ferrotto et al, 2018; Jiang and Teng, 2007; Khan et al, 2020; Lam and Teng, 2003, 2004; Lam et al, 2006; Lin and Teng, 2019; Mirmiran et al, 1998; Spoelstra and Monti, 1999; Shahawy et al, 2000; Smith et al, 2010; Teng et al, 2009; Rousakis et al, 2012; Xiao and Wu, 2003; Youssf et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Artificial neural networks approach for prediction of axial loading capacity of circular normal strength concrete columns confined by both transverse steel reinforcement and carbon fiber reinforced polymer wraps

Berradia

Alashker

Raza

et al. 2022

Advances in Structural Engineering

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A few empirical models for the axial loading capacity (ALC) of circular normal strength concrete (NSC) columns wrapped by carbon fiber reinforced polymer (CFRP) sheets and interior transverse steel reinforcement (TSR) (CSC columns) are available in the literature. The deficiency of those models is that they were proposed based on a small number of tests by considering limited parameters of CSC columns. Therefore, the main aim of the current investigation is to propose the improved empirical models for the ALC of CSC columns by including the interaction mechanism between TSR and FRP confining behavior. To secure this aim, a general regression analysis technique and artificial neural networks (NNs) on the experimental outcomes of 76 CSC columns collected from the previous investigations were employed. The proposed NN model was adjusted for the different number of hidden layers and neurons to achieve an optimized model. The suggested NN and empirical models portrayed a close agreement with the testing database with R2 = 0.998 and R2 = 0.892, respectively. The NN model reported a higher accuracy than the theoretical model. The comparative investigation solidly authenticated the superiority and accuracy of the anticipated strength models for CSC columns.

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Strengthening of deficient reinforced concrete columns subjected to concentric and eccentric loads

Cited by 6 publications

References 23 publications

Strengthening of reinforced concrete short columns using ferrocement under axial loading

Strengthening of reinforced concrete short columns using ferrocement under axial loading

Structural Behavior of Hybrid Reinforced Concrete Short Columns Under Uniaxial Load

Artificial neural networks approach for prediction of axial loading capacity of circular normal strength concrete columns confined by both transverse steel reinforcement and carbon fiber reinforced polymer wraps

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