Efficiency of Castellated and Cellular Beam Utilization Based on Design Guidelines

Abstract

Currently, castellated and cellular beams (CB) are being increasingly utilized in building construction, but the best design to maximize efficiency is still undecided by most engineers. In addition, the design efficiency characteristics of CBs in common use have not yet been disclosed. Therefore, this study was carried out to expose the efficiency conditions, reveal the states of governing modes in design, and provide design recommendations to obtain the maximum efficiency based on the AISC design guidelines. The results showed that the cost efficiency of fabricating an original steel-wide flange beam to a CB is possibly reduced due to the conservation of the design procedure given by the design guidelines. Overall, a castellated beam can be more efficient than the cellular beam because the applicable limitation of the castellated beam provided in the guidelines is wider than one of the cellular beam. Within the given limits, a cellular beams needs to have an approximate length at least 30 times its gyration radius (30rx) to obtain better efficiency compared to the original beam, while a castellated beam can adaptably be designed to acquire greater efficiency for relatively shorter and longer lengths. The hexagonal openings with wider web post widths, e, are needed to resist web post buckling for a relatively short beam length, while narrower web post widths are required to sustain the Vierendeel moment for intermediate beam lengths. The opening cut angle has a slight effect on the overall efficiency compared to other parameters.