Assessment of Cellular Beams with Transverse Stiffeners and Closely Spaced Web Openings

A computational parametric finite element analysis was carried out, investigating closely spaced cellular beams with double concentric transverse stiffeners. An unstiffened perforated beam section was initially designed and validated against existing finite element analysis results found in the literature. Then, twenty seven models were studied, while altering the spacing between the web openings, the web thicknesses and the stiffener thicknesses. The results showed that Vierendeel shearing failure occurred more frequently for very closely spaced sections. However, as the spacing increased, the contribution of the stiffener to strength of the section was decreased, and buckling failure occurred more often. A maximum distance for the spacing between the openings was suggested. At last, a design model was proposed, where for very closely spaced openings the compressive stresses were given by the Vierendeel moment capacity, and for the maximum distance of the spacing between the openings studied, the compressive stresses were given by a strut analogy, as found in BS5950–1.