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Flexural performance of cold-formed square CFST beams strengthened with internal stiffeners
Ahmed W. Al-Zand,W.H. Wan Badaruzzaman,Mustafa M. Ali,Qahtan A. Hasan,Marwan S. Al-Shaikhli 국제구조공학회 2020 Steel and Composite Structures, An International J Vol.34 No.1
The tube outward local buckling of Concrete-Filled Steel Tube (CFST) beam under high compression stress is still considered a critical problem, especially for steel tubes with a slender section compared to semi-compact and compact sections. In this study, the flexural performance of stiffened slender cold-formed square tube beams filled with normal concrete was investigated. Fourteen (14) simply supported CFST specimens were tested under static bending loads, stiffened with different shapes and numbers of steel stiffeners that were provided at the inner sides of the tubes. Additional finite element (FE) CFST models were developed to further investigate the influence of using internal stiffeners with varied thickness. The results of tests and FE analyses indicated that the onset of local buckling, that occurs at the top half of the stiffened CFST beam’s cross-section at mid-span was substantially restricted to a smaller region. Generally, it was also observed that, due to increased steel area provided by the stiffeners, the bending capacity, flexural stiffness and energy absorption index of the stiffened beams were significantly improved. The average bending capacity and the initial flexural stiffness of the stiffened specimens for the various shapes, single stiffener situations have increased of about 25% and 39%, respectively. These improvements went up to 45% and 60%, for the double stiffeners situations. Moreover, the bending capacity and the flexural stiffness values obtained from the experimental tests and FE analyses validated well with the values computed from equations of the existing standards.
Omar Ashour,Ahmad Muneer Alkhatib,Qusai Al Zureikat,Mustafa Al-Shaikhli,Basel Bani Ata,Talal Massad,Leen Al-Huneidy,Mohammed Qussay Al-Sabbagh,Abdallah Al-Ani 한국의학교육학회 2023 Korean journal of medical education Vol.35 No.1
Purpose: We aimed to evaluate the disparity between video-based learning and lecture-based learning on Jordanian medical students’ satisfaction. Methods: We conducted this cross-sectional study using a web-based questionnaire adapted from Student Evaluation of Educational Quality survey. Using convenience sampling, medical students studying at the University of Jordan and Jordan University Hospital were recruited. Participants in either clinical or basic-science years that have completed the entire survey were included in the final analysis. Results: We surveyed a total 487 participants among which male to female ratio was 1.19:1. Participants perceived greater benefit in terms of learning, instructor enthusiasm, content organization, breadth of teaching, and quality and number of assignments when using video-based learning (all p<0.01). In contrast, face-to-face learning was associated with significantly higher benefits in terms of group interactions (p<0.01) and capacity for rapport building (p<0.01). There was no significant difference in perceived examination performance between the two learning modalities (p=0.11). Conclusion: Video-based learning is the preferred learning modality among Jordanian medical students. Despite its dominance across multiple domains, it should be implemented as an adjunct to traditional classroom teaching for it is vital in the development of good communication skills and building rapport in medical students.