1スパン多層骨組の座屈荷重近似算定法について座屈モードを固有振動モードとしたエネルギ法による解析

摘要

The objective of this study is to propose an approximate calculation method of buckling load of a one-bay multi-story frame. In the analysis the energy method is adopted, and buckling modes and strengths are calculated as follows:1)Multi-story frame is disassembled into one-bay one-story unit frames. 2) Rotation angles and slopes of the members of the unit frame are determined by supposing the frame is subjected to horizontal load. 3) Horizontal displacement ratio along the height direction is assumed to be the same as the mode of vibration. 4) Mode of vibration is calculated by the Stodola method. 5) By equating the strain energy and the external work, the buckling load of the frame and effective lengths of the columns are obtained. An example of calculating method is shown and the comparison between the results by this analysis and those of the correct values by the buckling slope-deflection method is conducted in case of the one-bay two-story frame. ;Frame stability; Energy method. Buckling mode; Stodola method; approximate analysis method%鋼構造柱材の設計では柱材の座屈長さ係数の算定が重要である .近年の研究として，水平荷重による逆対称柱軸力に対しては， 座屈長さは材長以下になることが示されており，1次設計時の柱の 短期許容圧縮応力度の算定には筋違のない骨組においても柱の座屈 長さを階高にとることで安全側に評価できることが示されている.