大跨径悬索桥施工期暂态主缆不同时期截面形状并非成桥后的圆形截面,施工期暂态主缆存在发生驰振失稳的可能性。采用CFD数值模拟和有限元数值计算的研究方法,结合正在建设的东海某大跨径悬索桥,首次研究施工期暂态主缆未采取抗风措施时各工况截面的驰振力系数和驰振临界风速。结果表明:主缆施工前期工况1至3存在发生驰振失稳的可能性,施工后期工况4和5不会发生驰振失稳;东海某大跨径悬索桥施工期暂态主缆工况1风攻角为3°、4°和8°,工况2风攻角为-1°和1°以及工况3风攻角为-6°和5°对应驰振临界风速低于主缆施工阶段设计风速,即会发生驰振失稳。在数值分析的基础上初步研究了大跨径悬索桥施工期暂态主缆的驰振性能,研究结果可为大跨径悬索桥施工期暂态主缆的驰振稳定性分析提供理论参考。
The transient main cables during the construction of long-span suspension bridges are of non-circular crosssections, and thus may experience galloping instabilities. The galloping coefficients and critical wind speeds of the transient main cables for long-span suspension bridges without wind-resistant measures were investigated for the first time by means of the CFD and finite element software, with a reference to a suspension bridge. The results show that the galloping instabilities could occur only during early stages of construction of the main cables, but not for later stages. The galloping critical wind velocities with angles of incidence of 3, 4 and 8 degrees for case 1, -1 and 1 degrees for case 2, and -6 and 5 degrees for case 3 are smaller than the corresponding design wind speeds.