Wind field characteristics analysis at a long-span suspension bridge based on long-term monitoring data

In order to provide reliable basis for wind resistant evaluation of a long-span suspension bridge, the wind field monitoring system was installed and the simultaneous wind data at the bridge deck and the top of bridge tower were recorded. The variation of wind speeds with height, turbulent intensity, gust factor and turbulent wind spectra were analyzed by using statistical methods and spectral analysis. The results show that the dimensionless exponent is unstable at low wind speed and it decreases with the increase of the average wind speed. The mean statistical result is 0.161 at high wind speed, which is higher than the recommended value. The measured turbulence intensity also decreases with the increase of average wind speed, and it can be well fitted by exponential function. The mean statistical results of along-wind, cross-wind and vertical directions are 0.1806, 0.1564 and 0.0787, respectively, which are also greater than the recommended values. The gust factors have an approximately linear relationship with the turbulence intensities. The turbulence power spectrum can well fit the standard spectrum. However, the measured spectral values are considerably smaller in low frequency ranges.