Some times it is essential to cutout large openings from the web of cold formed steel beams and girders. These openings are required for the passage of utility ducts and piping. The behaviour and load carrying capacities of these beams may be significantly affected by the web openings. The reinforcement of these openings may limit the unfavorable effects on the behavior of the CFS beams.
The aim of this paper is to examine the different methods of openings’ reinforcements to enhance the behavior and load carrying capacities of CFS beams. The openings’ profile may have rectangular or elliptical configurations. The rectangular web openings were reinforced by folded edge stiffeners and by adding L-shape stiffeners. The elliptical web openings were reinforced using continuous and discontinuous punch out stiffeners. In this study, a single opening is considered on the mid-depth of C-cold formed beams at various locations along the beam span and at various loading conditions.
In the present study, the finite element method is adopted to investigate the effect of different shapes and types of web stiffening on the load carrying capacity of thin-walled beams. Large deformation formulation, as well as, elasto-plastic material response has been incorporated. For this purpose, the finite element computer package COSMOS 2.60 has been used throughout this study. The behavior and the failure modes of CFS beams subjected to shear, bending and combined shear and bending loadings have been studied.
In the light of the results of the performed finite element analysis, recommendations for the opening reinforcement of CFS beams with web openings were given. The paper demonstrates that, the designer can mitigate the detrimental effect of web openings by practical and cost effective reinforcement schemes.
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