Field Measurement Study on Wind Characteristics and Spatial Correlation at a Bridge Site in a Coastal Area

Wind field measurements were conducted at a long-span bridge in southeastern China using lidar and three-dimensional anemometers. Comprehensive mean and fluctuating wind characteristics were obtained, covering correlations and spatial distributions. The results reveal pronounced seasonal variations in wind speed, direction, and attack angle, with asymmetric distributions. Wind profiles were classified into three types: S-Type, Reverse Acceleration Type, and Exponential Type. A wind direction veering model was established for heights below 600 m. As wind flows over the bridge, it accelerates and turns counterclockwise, particularly near the shore. Fluctuating wind characteristics along the longitudinal, lateral, and vertical directions show significant deviations from standard models and vary systematically with wind speed. A three-parameter turbulence spectrum model tailored to coastal environments is proposed in this study. The study notes that correlations among fluctuating characteristics are stronger than those among mean values, with a clear inverse relationship between them. Quadratic fits are used to model the variation of wind speed, direction, and attack angle along the bridge. Turbulence intensity and gust factors increase near the shore, while the turbulence integral scale is slightly larger at midspan than at the side spans. Differences in mean wind characteristics between upstream and downstream vary with wind speed, particularly under Beaufort level 6 winds.