抄録
The bending moment of the beam is varied along the member under the dead load and lateral seismic load, and then the stress of the upper flange with the lateral bracings become compressive or tensile. Therefore the lateral bracings connected to flange need to have the lateral and rotational rigidity to prevent the lateral buckling of the beams when the upper flanges have the tensile stress. In this paper, the elastic lateral buckling load of H-shaped beams under moment gradient is developed with the energy method, and the relation between the elastic lateral buckling load and the required rigidity is clarified. Next, the elasto-plastic lateral buckling moment is evaluated using the modified slenderness ratio with the elastic lateral buckling load.
