中文摘要：

为了提高加劲梁的颤振性能，针对某三塔两跨公铁两用悬索桥进行了节段模型风洞试验，探讨了多种气动措施对加劲梁颤振临界风速的影响。结果显示，在三种风攻角下，常规气动措施如增加上下桥面板中央稳定板、铁路道板及检修道开槽等措施降低了加劲梁的颤振临界风速，封闭铁路挑臂并给合上桥面板上、下中央稳定板后，加劲梁在三种风攻角下的颤振性能均大幅提高，使颤振临界风速满足要求。相关结论可为类似桥梁断面的颤振优化提供借鉴。

英文摘要：

To improve the flutter stability of stiffened girder, the sectional model wind tunnel tests of a long span highway-railway suspension bridge with two main spans and three towers were carried out. A variety of aerodynamic measures on the flutter stability were explored. The results indicate that conventional aerodynamic measures such as the upper and lower central stabilizer, slotting rail road board and railway maintenance road reduce the critical flutter wind speed in three attack angle cases, while the flutter stability is increased significantly after closing the railway cantilever and u-sing the upper and lower central stabilizer in upper deck, which meets the requirement of standard. The conclusions can provide some references for similar bridge cross-section in the optimization of flutter stability.