Inelastic Behavior of Hybrid Cellular Steel Beams Made from Hot-Rolled Parent Sections

Abstract

Investigations carried out on cellular steel beams so far were mainly focused on the behavior of non-composite homogeneous sections. Hybrid I-beams are built-up sections where different steel grades are used for flanges and web parts. But perforated hybrid hot-rolled I-sections, where the top and bottom T sections would have different steel grades, can be achieved due to their cutting process. This paper presents a comprehensive parametric study focusing on the inelastic behavior of hybrid and homogeneous cellular steel beams made from hot-rolled parent sections. Finite element modeling using ABAQUS software was employed to validate previously tested hybrid and homogeneous cellular steel beams made from hot-rolled sections. To observe the effect of hybrid sections; the results of hybrid cellular steel beams were compared to the homogeneous ones of the same geometry but with different materials property. A broad spectrum of parent sections (section ratio), restraining conditions, spacing to opening ratio, span lengths, and various steel grades were included in the analysis. Results showed that the upper Tee is mainly the governing part in cellular beams. Moreover, the use of hybrid cellular beams with successive steel grades showed more compatible results compared to sections with non-successive grades for both restrained and unrestrained sections failing under global buckling. According to Eurocode 3 design rules, a set of modified equations were proposed to be used for the Lateral Torsional Buckling resistance calculations of hybrid cellular beams made from hot-rolled sections.