End-one-flange web crippling behavior of cold-formed high-strength steel channels with web holes at elevated temperatures

This paper investigates the web crippling strength of cold-formed high-strength steel (CHS) channels with centered web holes subjected to end-one-flange (EOF) loading at elevated temperatures, considering both flanges fastened and unfastened to load plates conditions. The stress-strain curve and material properties for CHS (S690QL steel grade) channels were adopted from the literature, where the temperatures ranged from 20 to 800 °C. The material characteristics were incorporated into finite element (FE) models using ABAQUS. The developed FE model was then validated against the published test results to evaluate the effects of various parameters including web hole diameter, bearing length, cross-section sizes, and flange fastening conditions of such channels at elevated temperatures, and a comprehensive parametric investigation including a total of 1710 validated finite element models was performed. From the parametric study results, it was found that the web crippling strength reduction factor is sensitive to the changes of the hole size and the bearing length, with the parameters of hole size having the largest effect on the web crippling reduction factor; however, the web crippling strength reduction factor remains stable when the temperature is changed from 20 to 800 °C. According to the FEA results, new reliable web crippling strength reduction factor equations for such CHS channels were proposed. In the comparison of proposed design strengths to the numerical failure load, the proposed design equations are suitable to predict the web crippling strength for CHS channels subject to EOF loading at ambient and elevated temperatures.