Structural behaviour of castellated steel beams with reinforced web openings

Abstract

In recent years, castellated steel beams, in steel structure buildings, have been employed extensively. There is common practice of adopting the depth of web openings up to 80% depth of the section. Due to large depth of web openings there is drastic reduction in the stiffness of the beams. The castellated beam becomes structurally more capable by providing the reinforcement (stiffeners) around the openings. Therefore in this research work, a nonlinear numerical analysis is carried out so as to observe the effectiveness of stiffeners provided around the periphery of the openings. From the results obtained it is found that robustness of castellated beams enhances by 44% as compared to conventional steel I beam. The average increase in strength of castellated steel beams by provision of stiffeners around openings is 36% over unreinforced openings. The web buckling failure can be prevented by using stiffeners around the openings. The predominant failure mode is found to be Vierendeel mechanism for both reinforced and unreinforced web openings.