半刚性连接钢框架的弹性屈曲荷载计算

以单层多跨框架结构为研究对象,通过对各梁柱构件建立失稳状态的控制微分方程并引入相应的连续性条件和边界条件,建立了半刚性连接平面钢框架结构整体弹性失稳的临界荷载计算模型,并研制了相应的计算程序。计算结果表明,框架结构的半刚性连接特性和水平支撑对其整体稳定性的影响极为显著,而且结构失稳的整体效应需引起高度重视。分析结果还表明,作用于多跨框架结构竖向荷载的分布特征对整体框架结构的弹性屈曲荷载有不可忽视的影响,而这一点在目前钢框架的设计理论中并未充分考虑。另外,半刚性连接特性及结构的支撑刚度对钢框架结构稳定性的影响具有明显的界限性和区间性,即当连接刚度或支撑刚度超过一定数值时,其变化对框架结构弹性屈曲荷载的影响将无需再考虑。

COMPUTATION OF BUCKLING LOAD OF STEEL FRAMES WITH SEMI-RIGID CONNECTIONS

A computational model of buckling load of steel plane frames with semi-rigid connections is put forward through establishing differential equations in buckling of the structures for each member of the structures and considering all the boundary conditions.The program is further developed and computaional results are presented.The results show that effect of joint flexibility and elastic bracing on buckling load of the structures is pronounced,which is valuable for considering the effect in design of steel frames against buckling of the whole structure.It should be especially noted that the buckling load or the equivalent buckling length factor of the plane steel structures are greatly influenced by the distribution of loads or ratio of loads,which was not considered well in present specification.The results show the other fact that effect of the semi-rigid connections and the stiffness of bracing elements on the buckling load of the structures(or the factor of equivalent buckling length) has a evident effect extent or limitation which show that variation of stiffness of semi-rigid connections and the stiffness of bracing elements will have no effect on the buckling length when the stiffness of semi-rigid connection or the bracing elements exceed a limited extent or value.