Aerostatic and aerodynamic stability of a suspension bridge during early erection stages

Abstract

During the early erection stages of suspension bridges, the flow field around the girder with a short length exhibits three-dimensional characteristics that affect the wind-resistant performance of bridges. To accurately extract the aerodynamic coefficients and flutter derivatives of a box girder during the early erection stages, three-dimensional computational fluid dynamics (CFD) models that balance accuracy and efficiency were established. Different angles of attack of the approaching flow were considered and the flow-field characteristics were discussed. With non-uniform wind loads distributed along the bridge axis, the aerostatic and aerodynamic stability of the bridge was investigated. The results show that the aerostatic and self-excited forces acting on the outer segments are different from those acting on the inner segments. The aerodynamic stability of the bridge is worse during the early erection stages. The end effect of the girder on the flow field is beneficial for the aerodynamic stability. Meanwhile, the structural aerostatic response has significant effects on the aerodynamic stability, which is also related to the angle of attack of approaching flow. Improvements in the aerodynamic stability can be achieved by adding counterweights inside the box girder.