Behavioural comparison between hybrid cellular steel beams and homogeneous cellular steel beams for different spans: Fid-Bau Portal

Behavioural comparison between hybrid cellular steel beams and homogeneous cellular steel beams for different spans

Desai, Ruturaj B. / Khatri, Ashish P.

Steel cellular beams are now being widely used for taking advantage of their role in enhancing the strength resulting from the increase in the depth of the beam. Hybrid cellular beam is the new form of cellular beams, in which for sagging bending moment, a higher grade of steel is used to frame the half part which will undergo compression and a lower grade of steel is used to frame the remaining half component to bear tension. It is important to check the buckling efficacy of hybrid cellular beams for different spans. In this numerical study the performance of laterally unrestrained hybrid cellular beams failing due to different possibilities of buckling under different loading conditions i.e., uniform bending moment, uniformly distributed load (UDL) at top flange and UDL at shear centre is investigated. For this, non-linear finite element simulations are performed on hybrid cellular beams made up of parent section HE 600 A and having different cellularity i.e., diameter of openings and spacing between the openings. The spans are chosen to achieve three different non-dimensional dimensional slenderness ratios (λLT); 1.6 for slender span beams, 1.1 for intermediate span beams and 0.8 for short span beams. The performance of hybrid cellular beam is compared with homogeneous low grade cellular and homogenous high grade cellular beams. It is determined from present study that the hybrid cellular beams performs better than or at par with the homogeneous cellular beams for considered different spans, loading conditions and cellularity. It is also observed that the extension of Eurocode 3 provisions for strength determination of hybrid short span cellular beams failing due to local buckling can lead to unsafe solutions.