ANALYSIS OF VORTEX-INDUCED VIBRATION CHARACTERISTICS OF XIHOUMEN BRIDGE

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.