柱脚に塑性を考えた水平力を受ける高層矩形ラーメンの柱耐力 (1)
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概要
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The paper consider the approximate safty load factor of tall steel frames which are not braced against horizontal lateral loads. The basic tool used in the derivation of a possible analysis method is that of the plastic collapse and the buckling collapse according to Kuranishi's Theory. Kuranishi states that "formation of some number of yield hinges bring about two kinds of collapse. One of them is the plastic collapse, the load for which, however, is appreciably reduced. In other cases, the load becomes heigher than the pure buckling load considering the existing yield hinges, and the equilibrium falls in unstable state to cause a type of instability which is called here the buckling collapse. Thus, the load limit for these two kinds of collapse is in general much lower than the conventional limit for the plastic collapse and the buckling". He showed the interaction diagrams of single-bay portal frames accurately, in order to illustrate his thory. However, his general theorem are too complicated to apply in practice as he admited. Then, the present writer has calculated to show the practical result of interaction diagrams of standard tall steel frames as following assumptions. 1. We take up single-bay rectangular frames with story n, rigidity ratio k and the radio of fully plastic bending moments at beams to columns β=M_<p′>/M_p, where, k=(EI_b/l)/(EI_c/h), h : height of the columns, l : span of the beams, EI_c, EI_b : flexural rigidity of the columns and beams, respectively. 2. The horizontal lateral load H at each floors and axial load P at columns are constant. 3. The parameter of diagrams are Z^2=Ph^2/EI_c, Qh/M_p, where Q=nH/2, and the value of n and k are variable as follows. n=1, 2, 3, 4, 5, 10, 15, 20 k=0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 4. The approximate limit ofβto produce the first yield hinges at their feet is investigated. 5. The interaction curve of the plastic collapse is conveniently simplified by the line as to drow from the point of pure buckling on the buckling collapse to the point of conventional limit for the plastic collapse in straight line. M. Kuranishi "On the Plastic Collapse and the Buckling Collapse of Structures" Rept. The Research inst. of Tech, Nihon Univ. No.5, Aug. 1962.
- 社団法人日本建築学会の論文
- 1965-03-28