Behavior of Thin‐Walled Steel Box Columns Under Biaxial Loading

Ultimate strength tests on welded thin‐walled steel box columns simply supported at the ends and subjected to biaxial loading are reported. A series of 28 large‐scale box columns of square and rectangular cross section were tested to failure. The parameters that were varied include plate slenderness ratio, column slenderness ratio, cross‐sectional shape, and eccentricity of loading. A description of the specially built test rig along with end fixtures and experimental procedures are also presented. Extensive measurements of welding residual stresses and initial column deflections were made. Stub‐column tests were also carried out. The test results show that the ultimate load‐carrying capacity of columns dropped with an increase in the plate slenderness ratio and an increase in the load eccentricity. The experimental failure loads of the tested columns are compared with the corresponding theoretical values obtained by the method proposed earlier by the writers.