Rotational capacity of castellated steel beams

This paper numerically studies the behavior of castellated beams with two simply supported ends under moment gradient loading and investigates the effect of beam and braced lengths on rotational capacity of castellated beams. To assure the ability of numerical models in predicting the complex behavior (especially at the location of opening) as well as the failure modes, numerical models of two experimentally tested specimens are developed. Comparison of force–displacement curves and failure modes shows that neglecting the boundary condition of the specimens, the numerical method can properly predict the behavior of castellated beams. All geometrical properties of the beams are the same as the study parameters so that the finite element model of the corresponding plain‐webbed beams can be easily created by filling the web openings in castellated beams. The accuracy of finite element models of plain‐webbed beams is evaluated by comparing the moment–rotation behavior with that of numerical models developed by other researchers. Rotational capacity of castellated beams derived from numerical models is compared with that of the corresponding I‐shaped plain‐webbed steel beams, and it is observed that in the case of short beams, web openings reduce energy absorption and plastic moment capacity of the beams compared with that of long ones. Copyright © 2012 John Wiley & Sons, Ltd.