考虑刚度折减的弹性二阶分析法在双跨排架结构中的运用

在框架结构设计中,构件的二阶效应采用一种实用且高效的考虑构件刚度折减的弹性有限元法来分析,该方法既能考虑结构的几何非线性又能考虑材料非线性,其准确性主要依赖于对构件刚度折减系数取值的合理性,但目前尚缺乏对排架结构的刚度折减系数的研究。以34个典型单层双跨等高排架结构为研究对象,进行最不利荷载条件下的弹性二阶分析和静力非线性分析,以排架结构整体二阶效应等效为基准,提出适用于双跨排架柱的统一刚度折减系数建议值;通过对多个双跨排架结构的非线性分析结果对比,验证了考虑刚度折减的弹性二阶分析法应用于排架结构的有效性,以及其刚度折减系数取值的合理性。

The application of elastic second-order method with considering stiffness reduction to two-span bent structure

Second-order effect of structural members is usually analyzed with a practical and effective elastic finite element method in the design of frame structure. The method considers the stiffness reduction of structural members, the structural geometric nonlinearity and the material nonlinearity, and its accuracy mainly depends on the rationality of stiffness reduction factor. Until now, there has no research on the stiffness reduction factor of the two-span bent structure. 34 typical single story equal-leg two-span bent columns were taken as the object to carry out the elastic second-order analysis and the nonlinear static analysis under the most unfavorable loads. Taking the equivalence of the entirety second-order effect as the target, a unified stiffness reduction ratio is suggested which is compliant to two-span bent columns. And the effectiveness of the elastic second-order method with considering stiffness reduction in two-span bent structure and the rationality of the stiffness reduction factor is proved through comparing the nonlinear analysis to multi two-span bent structures.