大比例主梁节段模型涡激振动风洞试验分析

Analysis of vortex-induced vibration of large-scale section model of girder in wind tunnel

节段模型风洞试验是预估大跨度桥梁主梁涡激振动响应的有效途径之一。大比例主梁节段模型(通常为1:15～1:20)几何尺度更大,试验雷诺数更接近实桥值,同时在模型加工制作方面也可更精确地模拟主梁细节。通过一扁平钢箱梁1:20大比例节段模型试验,优化了检查车轨道位置,分析了涡激振动典型现象如振幅、涡振区与阻尼、Scruton数关系,迎角与斯托劳哈数St关系,双竖向涡振区等,为节段模型涡振试验结果向实桥拓展提供理论与试验基础。

Section model wind tunnel test is one kind of effective method to estimate vortex-induced vibration （VIV） response of long span bridge girder. The large-scale （usually from 1 ： 15 to 1：20） section model has larger geometry scale. And the Reynolds number of large-scale section model wind tunnel test is close to that of prototype. Moreover, the geometry detail could be simulated more accurately by the large-scale section model. A large scale（1：20） section model of one flat steel box bridge girder was tested to get accurate VIV response and the optimized position of check vehicle rail. And several characteristics of VIV were discussed in detail such as VIV amplitude vs. damping ratio or Scruton number, VIV wind speed range vs. damping ratio or Sc, wind attack angle vs. Strouhal number, double vertical VIV phenomenon and so on. Theoretic and experimental foundation is provided here to expand the section model test result to prototype.