摘要
雅康高速兴康特大桥主桥为1 100m单跨钢桁梁悬索桥,加劲梁主桁采用带竖腹杆的华伦式结构,梁端设粘滞阻尼器。为评估该桥成桥动力性能,采用MIDAS Civil软件建立主桥有限元模型,分析动力特性;进行脉动试验,无障碍行车、制动、跳车和会车4种工况行车试验,对比分析主桥自振频率、振型,以及动应变冲击系数和动挠度冲击系数。结果表明:主桥计算基频较低,符合大跨度悬索桥柔性结构的一般特征,钢桁梁横向抗弯刚度较小,先出现侧弯振型;钢桁梁频率实测值大于理论计算值,实测振型无明显变异,整体刚度与质量分布达到设计目标,实测阻尼较小,实测纵飘振型较为滞后,支座、粘滞阻尼器有效削减了钢桁梁纵向振动;实测冲击系数较小,有障碍行车较无障碍行车冲击作用有所增强,未超规范计算值。
the main bridge of Xingkang Bridge on Ya′an-Kangding Expressway is a steel truss girder suspension bridge with a single span of 1 100 m.The stiffening girder adopts the Warren truss with vertical web members,and viscous dampers are installed at the girder ends.To evaluate the dynamic performance of the bridge in the completed state,the finite element model of the main bridge was established using MIDAS Civil to analyze the dynamic property.Different tests were carried to analyze the natural vibration frequency of the main bridge,vibration modes,dynamic strain impact coefficient and dynamic deflection impact coefficient,including the pulsation test and tests carried out in the contexts of no-barrier running,braking,bumping and passing each other.The results demonstrate that the calculated fundamental frequency of the main bridge is low,conforming to the general characteristics of flexible structures of the long-span suspension bridge.The transverse bending rigidity of the steel truss girder is small,with the lateral bending as the initial vibration mode.The measured frequencies of the steel truss girder are bigger than the theoretical values,and the measured vibration modes show no sign of evident mutation.The global stiffness and quality distribution reach the design objective,the measured damping ratios are smaller,and the measured longitudinal floating modes are relatively retarded,suggesting that the bearings and viscous dampers effectively suppress the longitudinal vibration of the steel truss girder.The measured impact coefficient is smaller,compared with the non-barrier running,the impact effect of running with barriers is intensified,but not exceeding the calculated values prescribed in the codes.
作者
陈杨
任东华
邹春蓉
CHEN Yang;REN Dong-hua;ZOU Chun-rong(China Railway Southwest Research Institute Co.,Ltd.,Chengdu 610031,China)
出处
《世界桥梁》
北大核心
2020年第4期45-48,共4页
World Bridges
关键词
悬索桥
钢桁梁
动力特性
频率
振型
冲击系数
有限元法
现场试验
suspension bridge
steel truss girder
dynamic property
frequency
vibration mode
impact coefficient
finite element method
field test
