Torsional Strengthening of RC Beams with Near‐Surface Mounted Steel Bars

Abstract

e strength of reinforced concrete members can be enhanced by using the externally bonded reinforcement (EBR) and nearsurface mounted (NSM) methods. However, very few studies have adopted the NSM method for torsional strengthening. Although previous studies have reported the efficacy of using epoxy-resin-bonded NSM steel bars in increasing the flexural and shear strength of RC beams, no study has examined the use of steel bars and epoxy adhesives for torsional strengthening.erefore, this study investigates the behaviour of RC beams subjected to the combined actions of torsion and bending moment when they are strengthened with NSM steel bars (Ø10 mm) in different configurations. e practical part of this investigation consisted of seven cast and tested beams of 150 × 250 × 2000 mm dimensions. One beam was reference, which is not strengthened; meanwhile, all the other beams were strengthened with two U-shape-welded NSM steel bars. During the testing process, the twist angle at the torque intervals, first cracking torque, ultimate torque, and ultimate twist angle of the conventional beam were compared with those of the strengthened beams. e torsional performance of the RC beams was significantly improved by using NSM steel bars, whereas in various NSM configurations, the 90°NSM beams outperformed the 45°NSM beams.

Enhanced Torsion Mechanism of Small-Scale Reinforced Concrete Beams with Spiral Transverse Reinforcement

“…A comparison of the experimental peak strength of test miniatures using spiral stirrups and closed stirrups with diverse spacing between stirrups. Geometrical similitude has been preserved stress similitude for the steel as shown in Equation 1 [23]. Table 3 show test results for prototype with diverse stirrups spacing.…”

“…As a result, constructing and testing economically viable reinforcing methods for boosting the torsional capacity of RC beams is an essential part. The staggered spiral tie is one of these techniques that has shown exciting results in increasing the torsional capacity [21][22][23][24]. The experimental torsional capacity values were compared to torsion strength values given by the ACI 318-14 [26] code and Eurocode-2 [27].…”

Numerical Analysis of Torsional Reinforcement of Concrete Beams in Unconventional by ANSYS Software

“…Thus, the performance of the structure is enhanced, so automatically the constructability is developed and the cost is lower [12]. In addition, Chalioris & Karayannis [13], and Askandar & Mahmood [14] found that using the spiral configuration as transverse reinforcement significantly improved the performance of torsional beams. Thus, the spiral stirrups used as transverse reinforcement in RC beams are considered a promising technique to improve both the torsional behaviour and the torsional capacity [15].…”

Effect of Near-Surface Mounted Bars on the Structural Behavior of One-Way Rc Slab

“…Most researchers have adopted carbon fiber reinforced polymer (CFRP) as strengthening materials due to its high strength to weight ratio. But there are very limited researches dealt with using steel bars as strengthening materials such as strengthening of corbels (Shakir and Kamonna 2018) shear strengthening of beams (Thamrin et al 2019), torsional strengthening of beams (Askandar and Mahmood 2020) flexural strengthen of continuous beam (Abdzaid and Kamonna 2019) and deep beams Al-Issawi 2018, Al-Issawi andKamonna 2020). There is very limited knowledge of adopting the NSM method by steel bars for strengthening of continuous one-way RC slabs, although it is availability in addition to it is ability of accounting of redistribution load beyond formation of plastic hinge which may occur in continuous members.…”