Behaviour of Steel Deep Beams in Moment Frames with Web Opening Subjected to Lateral Loading
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International Journal of Steel Structures https://doi.org/10.1007/s13296-020-00381-x
Behaviour of Steel Deep Beams in Moment Frames with Web Opening Subjected to Lateral Loading Masoud Hoseinzadeh Asl1 · Maryam Jahanian1 Received: 12 May 2019 / Accepted: 16 July 2020 © Korean Society of Steel Construction 2020
Abstract Due to the sharp change of the lateral load moment diagram in deep beams, the commonly proposed rigid connections may be incapable of proper transferring the plastic region away from the connection face into the beam. That is why prequalified connections of steel moment frames, proposed by different design codes, impose geometrical limitations on the beam spanto-depth ratio, which limits the application of the prequalified connections for short deep beams. The aim of this paper is to suggest details on leading the plastic area away from the column face by making a rectangular web opening at the mid-span of the deep beam. In order to stabilize the weakened area, stiffeners are used around the opening. 52 finite element models of deep beams with different geometries of the web openings are investigated. The results show that the use of deep beams with web opening located at mid-span in a steel moment frame is an efficient method to relocate the plastic hinge away from the connections, resulting in increased ductility. A parametric study is carried out on the effect of stiffeners dimensions, web thickness, and corner radius of web opening on behavior of deep beams in moment frames. A step-by-step design algorithm is also propounded for detailing of the web opening and the stiffener size. Keywords Steel moment frame · Web opening · Deep beam · Finite element analysis · Ductility
1 Introduction Beam depth and beam span-to-depth ratio are significant in the inelastic behavior of beam-to-column connections. As can be seen in Fig. 1, for the same induced curvature, deep beams will experience greater strains than shallower beams (AISC 358 2016). On the other hand, beams with low span-to-depth ratio have higher shear force which results in sharp change of the moment diagram along the beam length and this can result in reduction of the plastic hinge length in the beam which causes to increased plastic strains under inelastic rotation. In the short spans of moment frames, the demand in beams increases due to the high stiffness of the short span, which results in the increase of the beam size. On the other hand, AISC 358 (2016) recommends some limitations on the * Masoud Hoseinzadeh Asl [email protected] Maryam Jahanian [email protected] 1
Faculty of Civil Engineering, University of Tabriz, P.O. Box 5166616471, Tabriz, Iran
beam span-to-depth ratio for rigid connections. Due to these limitations, some engineers use simply supported beams in the short spans of the structure and ignore the possible lateral-load capacity of these spans. Since the short length moment frame spans are very effective in the lateral stiffness of the structure, ignoring the moment capacity of these spans c
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