无侧向支撑钢结构变电构架的二阶效应分析

针对无侧向支撑的两跨人字形钢结构变电构架,进行了考虑结构二阶效应的受力性能分析。分析中考虑了构架柱的初始几何缺陷,加载过程分别考虑了几何非线性、材料非线性以及两种非线性因素共同存在对变电构架受力性能的影响。通过分析对比斜向、水平及竖向荷载作用下的二阶弹性、一阶弹塑性和二阶弹塑性3条荷载—位移曲线,得到了这种变电构架的二阶效应特点及影响因素:在斜向和水平荷载作用下,虽然受材料非线性的影响更大,但受到二阶效应的影响较早;在竖向荷载作用下,则受二阶效应的影响更大,而塑性效应的影响不很明显。

Second-order Effect Analysis of Steel Structural Gantry of Switchyard with no Lateral Supports

The behavior of two-span character shaped steel structural gantry of switchyard with no lateral supports was analyzed in this paper considering second-order effect of the structure. Initial geometrical imperfection of gantry column is considered in the analysis, and geometrical nonlinearity, material nonlinearity and the two existing together are considered separately in the loading process, these factors have different influence on the behavior of gantry of switchyard. The characteristics of second-order effect and influential factors of this gantry of switchyard have been found through analysis and comparison of three load-displacement curves including second-order elastic curve ,first-order elastic-plastic curve and second-order elastic-plastic curve, which are obtained from three kinds of loads containing diagonal loads, level loads and vertical loads. The main conclusions are as follows ： under the action of diagonal and level loads, though the influence of material nonlinearity is greater, but the influence of second-order effect is earlier; under the action of vertical loads, the influence of second-order effect is greater, the influence of plastic effect is not obvious .