西堠门大桥涡激振动特征分析

ANALYSIS OF VORTEX-INDUCED VIBRATION CHARACTERISTICS OF XIHOUMEN BRIDGE

  • 摘要: 准确描述涡激振动的风场特征和动力响应特征是实现桥梁振动控制的前提,基于大跨度悬索桥结构健康监测系统获取的风场和振动加速度数据,对比分析了环境振动和涡激振动的风速、风向、湍流强度、阵风系数、脉动风功率谱密度、振动加速度及其功率谱密度的参数特征。结果表明:加劲梁典型的第6阶竖弯涡激振动中的风速可达7.24 m/s~12.24 m/s,风向基本垂直于桥轴向;三向湍流强度、阵风系数和脉动风功率谱在涡激振动中无明显不同于环境振动的特征。不同于多模态耦合的环境振动,涡激振动呈现单模态振动特征;通过功率谱峰值差异率量化该特征可区分环境振动和涡激振动。

     

    Abstract: The bridge vibration control needs accurate description of the wind field features and dynamic response characteristics of vortex-induced vibration (VIV). The parameter characteristics of wind speed, wind direction, turbulence intensity, gust factor, fluctuating wind power spectrum density, vibration acceleration, and its power spectrum density during ambient vibration and VIV were compared, using the data collected by the structural health monitoring system installed on a large-span suspension bridge. The results show that the wind speed of the typical 6th vertical bending VIV reaches 7.24 m/s-12.24 m/s, with the wind direction being nearly perpendicular to the bridge axis. The turbulence intensity, gust factor in three directions, and fluctuating wind power spectrum in VIV have no discernible differences from those in ambient vibration. Unlike the multi-modal coupling ambient vibration, VIV presents the characteristics of single-mode vibration. This characteristic can be quantified by the difference ratio of peaks in power spectrum to distinguish ambient vibration and VIV.

     

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