等截面斜腿刚架平面内整体稳定性能研究

用ANSYS有限元程序,考虑几何非线性,对等截面斜腿刚架进行了大量的荷载-位移全过程分析。分析中考虑了柱倾斜角度、柱高度与跨度比和梁的起拱坡度等参数,以及梁上均布荷载和集中力两种加载形式,最后给出了斜腿刚架的各种失稳模式和相应刚架柱的计算长度系数,供设计时参考。二阶弹塑性算例分析表明,在利用有效长度法进行斜腿刚架平面内整体稳定性验算时,除刚架柱外,还要验算梁的稳定性。

In-plane Global Stability of Tilted Column Portal Frame with Prismatic Members

Using the finite element program of ANSYS and considering elastical and geometrical nonlinear behavior,the load-displacement curves for lots of tilted column portalframes with prismatic members are obtained.The parameters such as column tilting angle,ratio of frame height to its span and gradient of beams are considered in the course of portal frame analysis under uniformly distributed loads or concentrated loads.Finally,different buckling modes of tilted column portal frames and corresponding effective length factors are proposed,which may be useful for design.Results of the elastic-plastic second order analysis for the portal frame with tilted columns indicate that the beam stability checking must be included in the calculation of stability using the effective length method.