【摘要】 涡激振动是影响铁路列车运行安全性和乘车舒适性的关键问题，也是铁路大跨桥梁抗风设计需要解决的重要问题。通过节段模型风洞试验，考虑攻角及阻尼的影响，研究铁路大跨桥梁流线型钢箱梁涡激振动性能。通过数值模拟方法分析主梁周围绕流形态，阐释铁路大跨桥梁钢箱梁的涡激振动发生机理与关键影响因素。研究结果表明，窄幅流线型钢箱梁在3°、5°风攻角，阻尼比0.30%时发生明显的竖向涡振；5°风攻角时主梁的最大无量纲振幅为3°时的2.28倍，涡振风速区间基本一致。布置无砟轨道及栏杆后主梁的竖向涡振消失，这是由于来流气流在主梁风嘴处分离，部分气流在迎风侧风嘴上斜腹板与桥面板交界处发生分离，产生的持续性旋涡的尺寸不断增大，运动至桥面背风侧并发生脱落，导致主梁发生涡激振动。无砟轨道板及栏杆使主梁背风侧旋涡的分离脱落位置远离主梁，减小对主梁的作用，优化其涡激振动性能。风嘴角度可减弱迎风侧桥面处气流的分离。研究成果可为同类铁路大跨桥梁钢箱梁抗风设计提供参考。更多还原

【Abstract】 Vortex-induced vibration(VIV) is a crucial issue that affects the safety and ride comfort of train operation, as well as an important problem that needs to be addressed in the wind resistance design of large-span railway bridges. Through segment model wind tunnel tests, considering the impacts of wind attack angles and damping ratios, this study investigated the VIV performance of steel box girder of a double-track railway bridge. The flow pattern around the girder section was analyzed using numerical simulation methods to explore the corresponding key influencing factors and explain the trigger mechanism of VIV for narrow girder section in long-span railway bridges. The results indicate that the narrow streamlined steel box girder exhibits significant vertical VIV at wind attack angles of 3° and 5°, and at a damping ratio of 0.30%. The maximum dimensionless amplitude of the main girder at wind attack angle 5° is approximately 2.28 times that of wind attack angle 3°, with basically consistent VIV wind speed range. The vertical VIV is eliminated for girders with ballastless tracks and railings. This is because, after the separation of incoming airflow at the wind fairing of the main girder, a portion of the airflow separates at the junction point of the upper inclined web and the bridge deck on the windward side, resulting in a series of continuous vortices. As the vortices travel along the bridge deck, their size increases and eventually sheds off at the junction of the bridge deck and the upper inclined web on the leeward side, causing vertical VIV. In condition of girders with ballastless tracks and railings, the separation position of vortices on the leeward side of the girder section is far from the girder, reducing the aerodynamic influence on the flow field and optimizing the vertical VIV performance of the girder. Also, the angle of wind fairing can weaken the separation of airflow at the windward side of the bridge deck. The research findings could serve as a reference for the wind resistance design of similar long-span railway bridge steel box girders.更多还原