地震作用下带斜面网架整体结构弹塑性时程分析

Elasto-plastic time-history analysis of holistic space truss structure with inclined plane under earthquake

斜面网架倾斜放置,两端支承柱之间存在很大的高差,造成了整体结构的质量和刚度分布明显不对称。对周边支承带斜面网架整体结构进行了地震作用下的弹塑性时程分析,并与平面网架进行了受力特性对比。分析表明:带斜面网架在水平x,y方向的整体受力特性有很大差别。斜面网架沿y方向(第二振型方向)运动时,高、低端支承柱和网架一起构成了整体性很强的抗侧力体系,y向水平地震作用按柱的侧移刚度分配剪力;沿x方向(第一振型方向)运动时,低端柱没有形成对高端柱的强有效约束,x向地震剪力由支承柱承受的荷载根据达朗伯原理确定;由于高、低端支承柱向与其相连的上弦、腹杆传递的轴力相差较大,地震作用下网架的内力分布呈现斜面网架的独特性。

The space truss with inclined plane is placed inclined and the supporting columns have large elevation difference,the mass and stiffness of holistic structure is evidently asymmetric. The paper carries on elasto-plastic time-history analysis for inclined space trusse,and compares with plane space truss in respect of stress features. The analysis shows： the whole stress features of inclined space trusses have large distinguish between x,y direstions. When inclined space trusses vibrate in direction of y（ direction of second vibration mode） ,the high-side and low-side supporting columns and space truss constitute a solid lateral resistant system,so the shear forces is distributed according to lateral stiffness of supporting columns under earthquake action in direction of y; when inclined space trusses vibrate in direction of x（ direction of first vibration mode） ,the low-side columns don＇t constrain high-side columns powerfully,shear forces in direction of x are determinated by loads that every column bear based on D＇Alembert Principle; because the axial forces that are passed from high-side and low-side columns to top chord and web member have much difference,the internal force distribution of inclined space truss has this unique character under earthquake action.