Document Type : Original Article
Authors
1
Master of Science in Civil-Structural Engineering, Faculty of Engineering, University of Maragheh, Maragheh, Iran
2
Assistant Professor of Civil-Structural Engineering, Faculty of Engineering, University of Maragheh, Maragheh, Iran
10.22065/jsce.2023.393962.3098
Abstract
The lateral-torsional buckling of beam is a disadvantage for connections with reduced beam section (RBS). One effective method for preventing such buckling is to reduce web section (RWS) instead of flange. This, not only eliminates the disadvantage of RBS, but also, provides better behavior and more ductility. This paper investigates the effect of longitudinal and transverse web/flange slits on the behavior of bolted steel moment frames. The investigated frames include: frame with full beam section and frames with beams reduced by: radial cut in flange, longitudinal slits in flange, transverse slits in flange, longitudinal slits in web, transverse slits in web, mixed web slits, and, cruciform web slits. These one-story one-bay frames are analyzed using nonlinear finite-elements method with shell elements of type S4R and solid elements of type C3D8R in ABAQUS. The quasi-static cyclic loading according to Supplemental Access Control protocol is applied to the frames. The results show that by using RWS beams, the location of plastic hinge can move from column face to an appropriate distance at the reduction region. According to the results, the maximum rupture index (RI) occurs in frame with full (not reduced) section; while, the minimum RI belongs to RWS frame with longitudinal web slits. The larger the RI, the greater is the probability of rupture at low drifts. The hysteresis curves of frames show that the strength of frames with longitudinal or transverse flange slits decreases at final step of loading, i.e. at the last two cycles with greatest rotation angles. The frame with longitudinal web slits with 31.8% more load-carrying capacity and 30.9% more energy dissipation, shows better performance compared to the other RWS or RBS frames.
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