Quantifying the impact of bridge geometry and surrounding terrain: wind effects on bridges

Abstract

The safety and serviceability of long-span bridges can be significantly impacted by wind effects and therefore it is crucial to estimate them accurately during bridge design. This study develops full-scale three-dimensional computational fluid dynamics (CFD) simulation models to replicate wind conditions at the Rose Fitzgerald Kennedy Bridge in Ireland. The neglect of bridge geometries and the use of small scales in previous studies are significant limitations, and both the bridge geometry and surrounding terrain are included here at full scale. Input values for wind conditions are mapped from weather simulations that apply the weather research and forecasting model. Wind velocities at four different points calculated by CFD simulations are compared with corresponding data collected from structural health monitoring field measurements. The calculated time-averaged wind velocities at four different locations on the bridge are shown to have relative differences of less than 10% from the wind velocities measured by anemometers 90% of the time. The maximum relative difference among all comparisons was only 15%, shown to be partially due to the inclusion of the full bridge and terrain geometry.