侧向支撑刚度对弧形闸门主框架稳定性影响

Impact Study of Lateral Supporting Stiffness for Main Frame Stability of Radial Gate

将弧形闸门主框架简化为有限侧移的弱支撑门式框架,为反映其实际屈曲模态,根据结构稳定理论,推导出了同时考虑柱端转动刚度和侧向支撑刚度单根轴心受压的柱端约束常数关系式,利用该关系式给出不同梁柱线刚度比、不同侧向支撑刚度情况下,弧形闸门主框架屈曲方程。通过试算给出相应的计算长度系数精确解,并给出了较高精度的实用计算公式。侧向支撑刚度Kb大于10对提高框架稳定的作用不再明显,认为强支撑和弱支撑的分界点为Kb=10;自由侧移和完全无侧移框架柱的计算长度系数差别极大,因此,侧向支撑刚度Kb对弧形闸门主框架柱的计算长度系数或屈曲荷载影响显著,在确定框架柱屈曲荷载之前首先要判明侧向支撑的强弱情况。

The main frame of the radial gate could be simplified to weakly braced gate-type frame with limited lateral displacement. In order to re-flect the actual buckling mode,according to the theory of structural stability,the expression of constraint constant considering rotational stiffness and lateral stiffness,was deduced by equilibrium equation of the concentrically loaded columns with the end restricted. Then the buckling equation of radial-gate frame at different crossbeam linear stiffness and lateral stiffness could be deduced,and the exact solution of the effective length factor was given by trial calculation. An example showed that the practical formula was of high precision and generally applicable. When lateral supporting stiffness Kb was greater than 10,the framework stability was no longer improving obviously that the divide point of strong support and the weak sup-port was taken as 10;Effective length factors were greatly large between freedom and rigid support frame,thus the lateral support stiffness Kb signif-icantly affect the buckling load,we must first ascertain the strength of lateral support before determining the frame stability.