H 形断面材の塑性曲げ捩れ座屈実験

Abstract

Tests on laterally unbraced H-shaped beam-columns were conducted to study the lateral torsional buckling strength and deformation behavior in the inelastic range. Beam-columns were subjected to constant axial compression and gradually applied end moments about strong axis of cross section. Main findings obtained from test results are as following : 1. Members with relatively large slenderness ratio collapse immediately after buckling initiates. Tangent modulus loads well correspond to ultimate strength of such members. 2. Members with relatively small slenderness ratio have a considerable post-buckling strength and failure is caused by the combination of lateral torsional buckling and local buckling of the compression flange. Tangent modulus loads are not reliable indices of ultimate strength of such members. 3. Most of specimens collapse suddenly after maximum bending moment in the member reaches a certain value. Thus the maximum bending moment may be taken for an index of failure of the members.