Analysis and Evalution of Buckling Loads of Spatial Arches Composed of Wide Flange Sections Considering Flexural Torsional Deformation

The present study discusses elasto-plastic buckling of spatial arches which are composed of members of H sections. The buckling analysis considers the flexural-torsional deformation of open sections. The members are H-600x200x9x16, and they are subjected to lateral-torsional deformation. Two types of supports are studied: pin-support and frame-support. The load conditions are two cases. One is uniform loading, and the other is non-uniform loading. First, elasto-plastic buckling loads under uniform or non-uniform loading, respectively, are calculated. For this calculation, a FEM beam element recently developed for open sections is applied, followed by a proposal for an evaluation method of buckling loads based on a normalized slenderness ratio. The normalized slenderness ratio is defined in terms of linear buckling load and plastic load, both of which are calculated using the axial force and bending moment of members. The validity is investigated through comparing the elasto-plastic buckling loads with the evaluated capacities, followed by confirmation of the preciseness and applicability of the evaluation method.