Prediction of maximum moment of rectangular tubes subjected to pure bending

In this paper, the collapse behaviors of rectangular tube subjected to pure bending are studied by using the finite element method. Such bending collapse has been studied for a long time, including the landmark study by Kecman. According to these studies, there are two types of collapses. The first type is a collapse due to buckling at the compression flange. The second type is a collapse due to plastic yielding at the flanges. However, there may be another collapse. For a rectangular tube in which the web is wider than the flange, it is found that collapse due to buckling at the compression web may occur. Further, an approximation prediction methods is proposed for estimating the maximum bending moment of rectangular tubes in which the web buckling is also taken into account. Its validity is verified by comparing with the numerical results by FEM under various conditions.