Experiments on Cold-Formed Steel C-Section Joists with Unstiffened Web Holes

AbstractExperiments were conducted on cold-formed steel C-section joists with rectangular unstiffened web holes. The presence of holes decreased joist capacity and amplified distortional buckling deformation. Distortional buckling was accompanied by unstiffened strip buckling of the compressed web. When hole depth approached the web depth, sudden buckling of the compressed flange and web above the hole was observed. Critical elastic buckling moments for local, distortional, and global buckling were calculated for each specimen including the influence of holes with recently introduced engineering expressions and finite strip analysis. Forthcoming direct strength method equations for cold-formed steel joists with holes were demonstrated to be viable predictors of flexural capacity for the specimens considered in the experimental program.