排架柱抗弯刚度折减系数探讨

采用构件折减刚度考虑二阶效应的弹性有限元法是新纳入中国《混凝土结构设计规范》较先进的结构分析设计方法,该方法的准确程度主要依赖构件折减刚度取值的合理性.鉴于该规范尚缺乏确定排架柱相应折减刚度的分析研究成果,以单跨工业厂房变阶排架柱为研究对象,通过对一系列典型排架结构算例进行最不利荷载条件下的非弹性有限元全过程模拟,并采用折减刚度的弹性二阶分析所得柱顶侧向位移与非弹性有限元模拟的柱顶位移等效为条件,选定了适用于排架柱的刚度折减系数后,再以所选刚度折减系数完成的弹性二阶分析所求得的各控制截面内力与非弹性有限元模拟结果的相符性证实了初选排架柱刚度折减系数的合理性.

Discussion of the Stiffness Reduction Factor of Bent-columns

The simplified structural analysis and design method employing stiffness reduction of member bars,has been accepted by Chinese Standard, in which second-order effects already been considered through elastic finite element analysis,and its accuracy mostly depends on the rationality of the stiffness reduction factor.Due to the absence of investigation in the stiffness reduction factor of bent frame,according to the non-linear finite element analysis of several single-story single-span bent frames,the stiffness reduction factor of bent-columns has been suggested.And the rationality of this factor has been proved by comparison of the internal force in bent-columns and displacement of bent frames in second-order elasticity analysis and non-linear finite element analysis.