Field Measurements of Wind Microclimate for Vehicle Levels on a Bridge Deck in a Complex Deep Canyon Terrain

Field measurements were conducted to investigate the microclimate wind environment at mid-span and tower regions. The characteristics of the microclimate wind environment around mid-span and tower regions were analyzed in depth, including average wind characteristics, turbulence intensity, pulsating wind power spectrum, and extreme wind. Wind profiles at mid-span and tower regions were analyzed. Subsequently, the vertical mean wind speed profiles at mid-span and bridge tower regions were statistically fitted. The wind speed distribution at bridge tower regions exhibits apparent shielding or acceleration effects. Therefore, a typical wind envelope curve across tower region was proposed along the driving direction. For the turbulence characteristics, turbulence intensities at tower regions are higher than those at the mid-span, representing a significant interference of the bridge tower and the neighboring terrains on the microclimate wind environment. Furthermore, the increasing turbulent energy at lower frequency domain is inconsistent with the variation characteristics of the -5/3 inertial subregion spectrum. Compared with the proposed spectrum from wind loading codes, a double logarithm 3-order polynomial was recommended to depict the energy distribution of the turbulence microclimate wind in the frequency domain. Generally, extreme wind speeds were also discussed. The results show that extreme wind speeds during the short term are more reasonable for evaluating vehicle driving safety in long-span bridges. © 2023 Xi'an Highway University. All rights reserved.