Field Measurements of Natural Wind Characteristics at Xihoumen Bridge

In order to provide reliable parameters for wind-resistant evaluation of Xihoumen Bridge, four 3-D ultrasonic anemometers were installed in the middle of the main span of Xihoumen Bridge. A long-term field measurement was carried out. The field data such as wind speed, wind direction, attack and yaw angles, etc, were measured. Detailed analysis of the field data and further study were conducted to investigate the wind characteristics. The measured wind data are analyzed to obtain parameters such as mean wind speed and wind direction, turbulence intensities, gust factors, turbulence integral length scales and spectrum of gust components. It is found that the turbulence intensities were larger than normal, and the ratio among the three components wasn't in good agreement with the recommended quantities in Wind-resistent Design Specification for Highway Bridges of China. And there was a tendency for the longitudinal and lateral turbulence intensities and gust factors to decrease with the increase of mean wind speed. The Kaimal spectrum and Panofsky spectrum models were identified to describe the energy distribution fairly well for the wind speed component in the longitudinal and vertical direction.