多跨连续桁架滑动支座设置分析

Analysis of setting sliding support for multi-span truss

为了了解三跨连续桁架仅进行单跨计算能否满足实际工程要求,采用三跨连续桁架仅端部设一个滑动支座(模拟实际工程)和每跨均设一个滑动支座(模拟单跨计算)的两个模型进行计算。结果表明,在恒+活荷载作用下,两个计算模型桁架内力无明显差别;在温度荷载作用下,仅有一个滑动支座模型近固端下弦杆产生很小轴力,但中间钢柱产生较大的剪力及底部弯矩,设计中应予以考虑。

In order to find out whether only single span calculation of the threespan continuous truss can meet the actual project requirements, two models of the three-span continuous truss with one sliding support only at one end （to simulate actual project）and one sliding support at each span are used for calculation（ to simulate single span calculation）. The results show that, under dead ＋ live load, there is no obvious difference between the internal forces of the two models. Under temperature load, little axial force produces in bottom chord near fixed end of one sliding support model, but large shear force and base moment produce in middle steel column, which should he considered in design.