新建宜万线渡口河大桥动力特性分析

Analysis of Dynamic Characteristics of the Dukouhe Bridge on Yichang-Wanzhou Railway being Built

新建的宜昌—万州线上的渡口河大桥为一座高墩大跨度连续刚构桥,为了研究其动力特性,分别按桩土连续梁模式、桩土空间刚架模式模拟桩土的共同作用,建立了相应的空间有限元模型。通过比较不同建模方法对动力分析的影响,深入分析了渡口河大桥的动力特性。研究了二期恒载、承台的质量、主墩的混凝土强度等级和边支座纵向弹性约束对结构动力特性的影响。计算结果表明,大跨度桥梁结构的动力分析必须建立详尽的分析模型,以反映结构的实际动力特性。

The Dukouhe Bridge which lies on Yiwan railway being built is a long-span continuous rigid frame bridge with high piers. In order to study the dynamic characteristics of the bridge, this paper builds up two 3D FEM models to simulate the pile-soil interaction with continuous beam model and spatial rigid frame model respectively. In comparision with other modeling methods for dynamic analysis,this paper investigates in details the dynamic characteristics of Dukouhe Bridge and the effect of the later applied dead load, the mass of cushion cap, the concrete strength grade of main piers and the longitudinal elastic restraint of side-bearings on the dynamic structural characteristics. The results show that long-span continuous rigid frame bridges should be modeled as precisely as possible to reflect their actual dynamic characteristics.