Effect of openings on the ultimate capacity of cold-formed channel steel beams

In this paper, a 3-dimensional finite element model is presented. The model is capable to predict the ultimate load capacity for spatially loaded cold-formed steel beams of open cross-sections. The treatment of both material and geometrical non-linearities is included in the model. The results of the proposed model are verified with the available experimental and theoretical results. Hence, the model is used to demonstrate the effect of the presence of openings located in the web on the ultimate capacity of cold-formed channel steel beams. A parametric study on six beams of different channel cross-sections and different size and location of web openings is initiated. The openings are chosen so that the effects of both their size and location are examined. Three sizes of openings are included in this study as a ratio between the diameter of opening and the depth of the flat portion of the web. The chosen size ratios are 0.2b, 0.50, and 0.75. For the three sizes of openings, the effect of the location of opening is examined as the second parameter; three locations are chosen in quarter, middle third and middle of the span. From the parametric study done, the effect of the presence of openings in the webs on the ultimate capacity of cold-formed channel beams is clearly evaluated. The results show that the two chosen parameters have considerable influence on both the ultimate capacity of beams as well as their modes of failure. © Faculty of Engineering Alexandria University, Egypt.