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.
Many researchers worldwide have extensively used fibre-reinforced polymer (FRP) strengthening materials and near-surface mounted (NSM) to enhance the shear and flexural strengths of reinforced concrete (RC) beams. However, studies on torsional strengthening are limited. Although a few studies have focused on torsional strengthening, none of them simultaneously investigated torsion with shear and/or bending moment. This study aims at demonstrating the behaviour of RC beams strengthened with FRP sheets (strips) with different configurations and NSM steel bars with different spacing that was subjected to combined actions of torsion and bending moment and making a comparison between them. Seven beams with a dimension of 15 × 25 × 200 cm were casted. One of the beams was not strengthened; three of them were strengthened with carbon FRP, and the others were strengthened with NSM steel bar. The angle of twist at torque intervals, first cracking torque, ultimate torque, and ultimate twist angle of the conventional and strengthened beams during the testing process are compared. Results show a significant improvement in the torsional performance of RC beams using carbon FRP and NSM steel bar. The test beams that were strengthened with CFRP wrapping showed better enhancement in the ultimate torsional moment as opposed to the beams that were strengthened with NSM steel bar.
The strength of reinforced concrete members can be enhanced using externally bonded reinforcement (EBR) and near surface mounted (NSM) methods. However, small number of studies has adopted the NSM method for torsional strengthening. To date, no study has examined the use of spiral NSM steel wire rope and epoxy adhesives for torsional strengthening. Therefore, this study examines the behaviour of RC beams subjected to the combined actions of torsion and bending moment when they are strengthened with spiral NSM steel wire rope (Ø8 mm) in different configurations. For this purpose, six beams of 15 cm × 25 cm × 200 cm were casted. One of these beams was conventional, whereas all the other beams were strengthened with spiral NSM steel wire rope. 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. The torsional performance of the RC beams was significantly improved using spiral NSM steel wire rope in various spiral NSM configurations.
Introduction: The first case of coronavirus disease 2019 (COVID-19) in holy Najaf city in February 22, 2020. The outbreak then rose up all over Iraq from 519 cases and 20 deaths in June 2, 2020 to 3484 cases and 72 deaths per day in August 10, 2020 per 24 hours. Aim: The aim of the study is to describe the distribution of confirmed cases by age, demographic factors, isolation, comorbidities and case fatality rate. Methods: Prospectively collected and analyzed data on patients with laboratory-confirmed 2019-nCoV infection by real-time RT-PCR and next-generation sequencing. The demographic and clinical outcomes data of 1153 diagnosed patients were collected from consecutive patients, analyzed, and described. About two third of cases 789 (68.4%) acquired infection through contact with positive patients. Results: The reported cases were 743 (64.4%) males and 410 (35.6%) females with large number among age range 21 to 50 years. The most frequent presenting symptoms were fever, sore throat and dyspnea or cough, most of patients; 868 (75%) patients were isolated at home versus 285 (24.72) patients required hospitalization which represented the intermediate and sever cases. The overall case fatality rate was 2.4%. Conclusion: Most of COVID-19 cases in this localitywere male from urban areas. The common onset symptoms were the fever, sore throat and dyspnea or cough. Majority of cases were isolated and treated at home. The estimated case fatality rate was within the global range (2.4%).
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