AN APPROXIMATE BEAM MODEL FOR H-SECTIONS CONSIDERING LATERAL TORSIONAL DEFORMATION AND ITS APPLICATION TO BUCKLING ANALYSIS OF SPATIAL STRUCTURE

Abstract

The present study investigates an approximate FEM buckling analysis method for H-section beams, in which the effects of torsional and warping rigidity are included using traditional beam-column elements, followed by its application to materially and geometrically nonlinear buckling analysis of an arch structure and a unit dome. The approximate-beam model consists of three parallel beam-column elements deforming independently which enables the model to express lateral torsional buckling deformation of members. The validation of the proposed beam model is confirmed by both beam theory's solutions and 3-D FEM analysis. The present approximate-beam model, applied to an arch structure and a unit dome, proves its efficiency in buckling analysis. The results show that the torsional and warping deformation of H-section beams are relatively large and cannot be neglected in buckling load evaluation. The present model based on the compound use of traditional three-beam elements is concluded to be capably applied to H-sections under nonlinear torsional and warping deformation.