Effect of Beam Length and Braced Length on Moment-Rotation Behavior of Castellated Beams

The presence of web openings in castellated beams introduces different modes of failure at the perforated sections such as excessive stresses in tee-sections, excessive stresses in mid-depth of the web post, web-post buckling, developing plastic Vierendeel mechanism. This paper presents nonlinear behavior of castellated beams under moment gradient loading and investigates the effect of beam length and braced length on moment-rotation behavior and ductility of this type of beams. Accuracy of finite element models of plain-webbed beams is evaluated comparing moment-rotation behavior and failure mode of other researchers’ numerical models and cleared a satisfactory accuracy. Rotational capacity of castellated beams, derived from numerical modeling, is compared with corresponding I-shaped plain-webbed steel beams and it is cleared that for the short beams, web openings reduce energy absorbance and plastic moment capacity of the beams more than long ones.