Abstract
In designing of bracing members in plastic design the following three aspects play a significant role : (1) spacing of the bracing members (2) strength of the bracing members (3) rigidity of the bracing members. In previous reports, I. II. III., the bracing space has already been studied for the case of the lateral movement of bracing point entirely constrained. In this paper an attempt is made to understand the rigidity problem in bracing members quantitativly by experiment; experiments and numerical analysis are mainly on the axial rigidity of bracing members. Experiments were made with a reaction frame; a general view of the test apparatus in shown in Photo. 1. As shown by the experimental results, the strength and rigidity of a bracing member has large influence on the deformability of the main beam. Ingeneral, the larger the strength and rigidity of a bracing member, the greater becomes the deformability of the beam. By the present experiment, the necessary rigidity in the bracing member, at the bracing space L/r_y=40 as specifid in the draft standerds is about 50% of that given in A. I. S. C's standards. The axial force in the bracing member can be about 3〜4% of the axial stress in the main beam. In the influence of the rigidity and strength of a bracing member upon the deformability of the main beam are involved the buckling effective length factor k and the movement of a bracing point u; these may be used to an advantage in the present problem. As described so for, the axial rigidity in bracing member has been studied by experiment and by numerical analysis and its quantitative grasping could be achived. For the pending rigidity, however, only its behavior was observed; and the quantitative study is in progress at present.
