Abstract
The beam-to-column connections play a key role in determinating whether structures will reach it's ultimate load or not. So the connections must provide for a sufficient strength, rigidity and plastic quality. Ordinarily in the beam-to-column connections, when the beam flange force is transmitted to the column flange and web, the stress surface is abruptly changed and then the stress distribution is remerkably irregu-lated For instance, the local deformation of the column flange by the concentrated beam flange force causes the stress concentration in the beam flange and column web, so that fracture is most likely to start at the middle point of the column flange where it is restrained by the column web. This paper investigates these phenomena in the H-type beam-to-column connections and indicates the effective width of the column web and the degree of stress concentration in the beam flange. The column flange thickness effects excessively on the effective width of the column web and stress concentration in the beam flange. When the column flange is thicker than the beam flange the effective width decreases remarkably. In the result of numerical calculation, when the column flange thickness is no less than beam flange thickness, the effective width is about 0.85a_c (a_c: column flange breadth) and maximum stress in the beam flange reaches 1.6〜2.0 times mean stress.
