Spatial stability of braced thin-walled members of steel structures

Abstract

Abstract The solutions of the spatial stability problems for: (1) monosymmetrical columns and beams with a prescribed axis of rotation, compressed and bent under transverse loading and (2) monosymmetrical beams with a horizontal (lateral) brace, loaded with an arbitrary number of concentrated forces are provided. The considered structural members were additionally point braced along their length to prevent them from twisting and warping. The spatial stability problems were formulated as distributional differential equations, which were solved approximately using the Bubnov–Galerkin orthogonalization method and then the solutions of the problems were derived for the structural members for different support conditions at their ends. The general solutions were reduced to eigenvalue problems. The numerical calculations can be performed using in-house computer programs. Each of the considered problems is illustrated by numerical examples and ready-made particular solutions. In the case of the beams with a lateral brace, also the effect of stiffeners on the lateral buckling load was examined. The theoretical solutions have been validated by model tests carried out on laterally and longitudinally braced steel I-section columns subjected to compression and bending and on longitudinally braced steel I-beams.