【摘要】 以规划的贵州某PC板式加劲梁悬索桥为研究对象,针对施工和成桥两种状态,利用节段模型强迫振动风洞试验,识别了-3°、0°和3°三个风攻角下PC板式加劲梁的8个颤振导数。通过有限元软件ANSYS的二次开发,对大桥进行了颤振全模态频域分析,研究不同风攻角和栏杆对该桥颤振特性的影响。研究发现,在0°风攻角下,栏杆(成桥状态)显著恶化了加劲梁的颤振特性;无论是施工状态(无栏杆)还是成桥状态,负攻角下大桥颤振临界风速显著降低;相反,正攻角下施工和成桥均有很高的颤振临界风速。这表明,此类PC板式加劲梁悬索桥对来流风攻角非常敏感,栏杆气动外形优化和桥址风场条件研究非常重要。更多还原

【Abstract】 Based on the tentative design of a suspension bridges with PC slab stiffening girder in Guizhou Province,the sectional model wind test was carried out to identify flutter derivatives of the stiffening girder,by using forced vibration technique at the wind attack angles of-3°,0°and 3°.With a second development of the software ANSYS,the full-mode flutter analysis of the bridge in frequency domain was implemented,considering the influence of wind attack angle at construction stage or in-service state.It is found that the presented handrail on the stiffening girder apparently promotes bridge flutter instability at zero angle of attack;at either construction stage or in-service state,the flutter onset wind speed of the bridge is significantly decreased at negative angle of attack;while very high flutter onset wind speed occurs at positive angle of attack at either construction stage or in-service state.Because of the very sensitive flutter instability of such kind of bridge to wind angle of attack,studies on the suitable selection of the handrail shape as well as the wind environment at bridge site should be highlighted.更多还原