Investigation on Wind Characteristics for a Bridge within a Mountainous Area Via Wind Tunnel Test of Terrain Model

Abstract

Wind tunnel tests of a 1/2200 scale mountainous terrain model have been carried out to investigate local wind characteristics at a bridge site in southeast Tibet, China. Flows past 5 key sites of the bridge at the deck level in 26 directions were measured. Flow was also measured at each pylon at 32 additional different levels in these directions. It was observed that profiles of wind characteristics (including mean wind velocity, overall turbulence intensity, yaw angle and wind attack angle) at each pylon vary significantly depending on the approaching wind direction, and the majority of mean wind profiles cannot be presented by the normal profile. The wind attack angle at the deck level measured in the study fluctuated between -16° and +18°, and mean wind velocity to the reference wind was small when the wind attack angle was large, especially at positive wind attack angles. The design standard wind speed and the minimum critical wind speed for flutter rely on the wind attack angle and should be determined by results of the tests.