Flexural Strength Evaluation for Cold-Formed Steel Lip-Reinforced Built-up I-Beams

Abstract

In order to investigate the flexural behavior of cold-formed steel lip-reinforced built-up I-beams, a total of 9 I-beams with three series and 3 identical specimens for each series are tested, and test specimens are simulated by finite element analysis. Results of finite element analysis and experimental results agree well, proving the validity of the finite element method in this paper. Then, substantially parametric analyses are carried out through this finite element model and the following conclusions can be obtained: the steel grade and width-to-thickness ratio of flanges have great influence on the effective width-to-thickness ratio of compression flanges, while the length of the beam, the height-to-thickness ratio of the web, and the thickness of the plate have relatively little influence. Finally, based on results of parametric analyses, effective width method and strength-reduction method on ultimate load-carrying capacity of cold-formed I-beams are proposed. Moreover, tables and equations, which are used to determine the effective width-to-thickness ratios of compressed flanges or strength-reduction factors of built-up I-beams with typical sections, are gained. The ultimate load-carrying capacity from these methods agrees well with experimental results. Therefore, the effective width method and strength-reduction method in this paper are valid and are able to be applied in practice.