Development of elastic lateral buckling stress for H-shaped beams with lateral-rotational braces subjected to axial force from dampers

摘要

H-shaped beams connected to steel dampers are subjected to compressive and tensile forces in addition to flexural moment, and then the buckling behavior of H-shaped beams under axial force and flexural moment is more unstable than that under only flexural moment. In this paper, the lateral buckling behavior for H-shaped beams with the lateral bracing under the flexural moment and axial force is clarified. First, the elastic lateral buckling load of H-shaped beams is developed with the energy method, and the relationship between the lateral buckling load and the bracing rigidity is clarified. The bracing rigidities consist of the lateral and rotational rigidities. The required bracing rigidity is developed from two equations of the elastic lateral buckling load. Next, large deformation analyses are performed using the numerical analyses program ABAQUS with version 6.13, and the elasto-plastic lateral buckling behavior for H-shaped beams with lateral and rotational bracings is presented. Finally, the lateral buckling load for H-shaped beams with the required bracing rigidity is estimated with the modified equivalent slenderness ratio, and the elasto-plastic buckling stress is compared with the buckling curve for Japanese standard code.