Behaviour of Steel Deep Beams in Moment Frames with Web Opening Subjected to Lateral Loading

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 span-to-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.