大跨度铁路连续刚构-CFST拱桥动力特性试验研究  

Experimental study on dynamic characteristics of long-span railway continuous rigid frame-CFST arch bridge

作　　者：秦世强[1] 冯嘉诚 唐剑 霍学晋[2] QIN Shiqiang;FENG Jiacheng;TANG Jian;HUO Xuejin(School of Civil Engineering and Architecture,Wuhan University of Technology,Wuhan 430070,China;China Railway Bridge Survey and Design Institute Group Co.,Ltd.,Wuhan 430074,China)

机构地区：[1]武汉理工大学土木工程与建筑学院,湖北武汉430070 [2]中铁大桥勘测设计院集团有限公司,湖北武汉430074

出　　处：《铁道科学与工程学报》2021年第12期3247-3256,共10页Journal of Railway Science and Engineering

基　　金：国家自然科学基金资助项目(51608408);中央高校基本科研业务费专项资金资助项目(2017IVB046)。

摘　　要：宜万铁路宜昌长江大桥主桥为连续刚构-钢管混凝土(CFST)拱组合结构,为了评价其在列车荷载下的动力特性及行车安全,利用现场行车、制动及环境振动试验数据,结合有限元模型对其进行动力特性分析。首先,介绍桥梁的工程概况及动力试验安排。其次,利用环境振动试验得到结构的加速度响应,结合频域和时域分析获得桥梁的频率、阻尼比和振型;通过行车和制动试验,得到关键截面的应变、加速度和振幅。最后,计算脱轨系数和轮重减载率评估行车安全性。结果表明:桥梁频率和阻尼满足规范要求,加速度和位移峰值都较小,表明结构有足够的刚度;相比列车行车工况,制动工况对桥梁的冲击效应更为显著;各截面相同工况下竖向加速度峰值明显大于横向加速度峰值,表明列车作用下桥梁竖向振动更为剧烈;双向行车工况下,拱肋截面的动力系数和加速度峰值均小于主梁截面,表明柔性拱肋具有更好的动力性能;脱轨系数小于规范限值,列车运行安全。The main bridge of Yichang Yangtze River Bridge on Yiwan Railway is a continuous rigid frameconcrete-filled steel tube(CFST) arch composite structure. In order to evaluate its dynamic characteristics and driving safety under train load, the data from on-site driving, braking and environmental vibration tests were used in combination with the finite element model. Dynamic response analysis was carried out. First, the engineering overview and dynamic test arrangements of the bridge was introduced. Second, the acceleration responses of the structure were obtained by the environmental vibration test, and the frequency, damping ratio and mode shape of the bridge were obtained by combining the frequency domain and time domain analysis;and the strain and acceleration responses and amplitudes of the key sections were obtained through the driving and braking test.Finally, the derailment coefficient and wheel load reduction rate were calculated to evaluate driving safety. The results show that the bridge frequency and damping meet the specification requirements, and the acceleration and displacement peaks are small, indicating that the structure has sufficient rigidity;compared to the train operation condition, the braking condition has a more significant impact on the bridge;all sections are the same. Under the conditions, the peak vertical acceleration is obviously greater than the peak lateral acceleration, indicating that the vertical vibration of the bridge under the action of the train is more severe;Under two-way driving conditions, the dynamic coefficient and peak acceleration of the main beam section are larger than the arch rib section, indicating that the flexible arch rib has better dynamic characteristics;the derailment coefficient is less than the specification limit, and the train runs safely.

关 键 词：桥梁工程 连续刚构-CFST拱组合结构 动载试验 环境振动试验 冲击系数 模态参数 脱轨系数 

分 类 号：U24[交通运输工程—道路与铁道工程]