コーナー・ブラケット所要板厚の一決定法

抄録

In this paper, a study was made on buckling and plastic behavior of a corner bracket which is attached to the beam and frame. In order to make the beam most effective, one requirement is that the bracket should neither elastically buckle nor plastically collapse, before the beam reaches the plastic collapsing state, forming the plastic hinges at the toes of brackets and the center of the beam which is assumed to be subjected to uniformly distributed loads. A method of calculation is proposed to determine the necessary thickness of the bracket so as to fulfil the requirement.
The procedure of calculation is as follows : (1) to calculate the plastic collapse load of the beam, (2) to determine the stress distribution in the bracket under the plastic collapse load. of the beam, (3) to choose the requirement either elastic buckling for thinner plate or ultimate strength for thicker plate of the bracket, and (4) to determine the necessary thickness so as to satisfy the requirement.
Elastic-plastic large deflection analysis by FEM was carried out on several beams with brackets whose thicknesses were determined by the proposed method and the results demonstrated that the method was simple and useful. The necessary thickness calculated by the method was compared with that by the NK rule.