Abstract：The computational procedure of 3D refined flutter analysis is used to analyze the wind stability of long-span suspension bridge under skew wind. Considering the structural nonlinearity, the aerostatic effect and full-mode coupling effect, flutter stability of the Runyang suspension bridge over the Yangtze River in completion and during the whole construction period of the girder segments erected symmetrically from the midspan to towers is numerically investigated under the skew wind. The influence laws of skew wind and aerostatic effect on flutter stability of long-span suspension bridge under the service and construction conditions are obtained. The results show that the critical flutter wind speed of suspension bridge under service and construction conditions fluctuates with the wind yaw angles, and reaches to the lowest value under the skew wind. The skew wind and aerostatic effects do not change the evolution of flutter stability of suspension bridge during the construction period, but significantly reduce the flutter stability of suspension bridge under the service and construction conditions. The average maximum reduction of critical flutter wind speed under the skew wind effect is 8.0% and 19.6% respectively for the bridge under the service and construction conditions. The combined effect of the aerostatic and skew wind further degrade the flutter stability of suspension bridge, and the average maximum reduction is 11.5% and 22.4% respectively under the service and construction conditions. It is concluded that the adverse effects of the static and skew wind should be considered in the flutter stability analysis of long-span suspension bridges under service and especially construction conditions.
