既有线路提速改造中下承式钢桁结合桥的应用研究

Study of through truss composite bridges in the speed-up reconstruction of lines under service

我国既有线路上运营的许多 4 8m以上的钢桁桥多为明桥面桥 ,提速后其刚度均达不到运营的要求 ,而且噪音大 ,给沿线造成污染 ,需要在桥的技术和结构等方面进行改造。在研究中 ,以 6 4m双线铁路钢桁梁桥为例 ,将其换成小节间 4纵梁半结合下承式钢桁桥 ,采用空间有限单元法对其强度、刚度和动力特性作了全面系统的分析 ,其结果均满足要求。研究结果表明 :将原钢桁桥换成下承式钢桁结合桥 ,可基本不改变桥头线路高程和桥梁下部结构 ,该方法既快捷又经济 。

There are many steel truss bridges with spans larger than 48m on the service railway lines in China. After speed up, their stiffness is not available any more and their noise is too high and pollutes environment and needs reconstructing. The height of the line adjacent the bridge and the sub-structure of the bridge need not change if through truss composite bridges take the place of them. This is the most simple and economical method. As an example, the 64m double-line through truss semi-composite bridge with small panels and 4 stringers take the place of the through truss bridge. Using space finite element method, its strength, stiffness and dynamic properties are analyzed and all of them are satisfied. It shows that this method is effective.