断索工况下风攻角对曲梁单边斜拉桥动力响应影响分析

Analysis of the Effect of Wind Attack Angle on the Dynamic Response of Curved Girder Single-Sided Cable-Stayed Bridges Suffering from Cable Breaking

风攻角的变化可能会对桥梁的风致振动产生不利影响。基于有限元模拟和节段模型风洞试验,分析了5种风攻角工况下曲梁单边斜拉桥的风振响应。结果表明:在断索全过程中,随着风攻角的增大,桥梁跨中位移和加速度极值以及拉索张力均先增大后减小且在15°时达到最大,在抗风设计中应着重考虑最不利风攻角。动力放大系数(dynamic amplification factor, DAF)推荐值应考虑风攻角15°时拉索断裂引起的风振放大效应,有助于为同类型桥的抗风设计提供借鉴。

Changes in the wind attack angle may adversely affect the wind-induced vibration of the bridge.Based on the finite element model and the wind tunnel test results of segmental model,the wind-induced responses of single-span cable-stayed bridges with curved girders under five different wind attack angles are analyzed.The results show that with the increase of wind attack angle,the extreme values of mid-span displacement,acceleration and cable tension of the bridge first increase and then decrease,and reach the maximum value at 15°.The most unfavorable wind attack angle 15°should be considered in the design of wind resistance.The recommended value of DAF should take into account the amplification effect of wind vibration caused by cable breakage with the wind attack angle 15°,which is helpful for the study of wind resistance design of similar type bridges.