Author(s)

Y. Kimura

Abstract

This paper clarifies the flexural buckling load of H-shaped compression members with lateral support at their half length and the required rigidity of the lateral supports. In this study, the braces used as lateral supports are eccentrically jointed to the compression members in their sections. The buckling load of the members with eccentric support is calculated by the energy method and the elastic eigen-value analysis, and then the braces are replaced by lateral and rotational springs. This paper evaluates the rigidity demand equivalent to immovable lateral supports and also confirms its effect using inelastic large deformation analysis. Keywords: H-shaped compression members, eccentric braces, energy method, FEM, required rotational and horizontal stiffness. 1 Introduction When the space structures are subjected to the seismic forces, their members carry the large compression or tension stresses. In general, their compression members are designed not to buckle by Allowable Stress Design, and they have some braces which need some lateral stiffness to prevent buckling deformation of compression members. The value of the required lateral stiffness is shown in Japanese Design Standard for Steel Structure [1], but in the real structure, the braces may not be jointed with the compression member into the center of its section. The structural members in the truss frame are usually jointed with non-structural members, which may be effective to prevent the flexural buckling of the structural members subjected to compression load. But their joints are eccentric, so the torsional bucking may occur with its flexural buckling of the

Keywords

H-shaped compression members, eccentric braces, energy method, FEM, required rotational and horizontal stiffness.