门式刚架三阶柱计算长度系数的计算方法

CALCULATION METHOD OF EFFECTIVE LENGTH COEFFICIENT OF THREE-STEPPED COLUMNS IN PORTAL RIGID FRAMES

基于梁柱线刚度比和半刚性节点对三阶柱计算长度的影响,通过对一榀三阶柱门式刚架的屈曲分析,得出了三阶柱计算长度系数。目前,多数厂房计算模型被简化为梁柱刚接有侧移模型,忽略梁对柱的约束及半刚性节点对柱计算长度的影响。这种简化与梁柱实际受力情况出入较大,故采用理论公式与有限元计算相结合的方法,考虑梁柱线刚度比和半刚性节点对柱子计算长度系数的作用,与以往简化模型得出的计算结果比较可知,这两种因素对三阶柱计算长度系数的影响不可忽略。

Based on buckling analysis of portal rigid frames of three-stepped columns, the brief factors, the linear rigidity ratio of beam and column and semi-rigid connection , were discussed, the effective length coefficient of three-stepped columns was obtained. Now many industrial buildings were simplified as this kind of model which had lateral displacements and rigid connection between beam and eolunm. When being analysed, the influence of restrains from beam to column and semi-rigid connection were often neglected, so the results were inaccurate. The method of academic formula and finite element were used, the effective length coefficient could be recalculated refering to linear rigidity ratio of beam and column, then the result considering these two factors was obtained. So the conclusion that the effective length coefficient of three stepped column considering these two factors was preciser than before.