Abstract: When a curved bridge constructed using the rotation method suddenly stops during rotation, the bridge will withstand inertial forces, self-weight, and wind loads, which may cause significant deformation and local structural instability, leading to engineering accidents. On the basis of stability research on swivel construction, the main consideration is the influence of rotational speed and wind speed on the out of plane stability coefficient of the bridge. Taking a railway crossing an existing railway as an example, the out of plane stability coefficient of the bridge is taken as the control objective during the swivel construction process. Through stability theory analysis, equations between rotational speed and out of plane stability coefficient, as well as equations between wind speed and out of plane stability coefficient, have been established during the swivel process. The results show that when the rotational speed is low, the wind speed has a greater impact on the stability of the rotating system, while when the rotational speed is high, the wind speed has a smaller impact on the stability of the rotating system. When the wind speed is low, the emergency stop time has a greater impact on the stability of the rotating system, while when the wind speed is high, the emergency stop time has a smaller impact on the stability of the rotating system. To ensure the safety of the rotating construction process, the rotational acceleration should not exceed 0.1°/s² when the wind speed is less than 8 m/s. When the wind speed is 8 m/s-18 m/s, the impact of the speed on the external stability coefficient k₂ is relatively small, and the speed can be controlled within 0.01 rad/s while ensuring safety.

Key words: curved bridge, swivel method, stability

摘要： 采用转体法施工的曲线桥,在转动过程中突然停止时,桥梁会承受惯性力、自重和风荷载作用,可能会产生较大变形,引起结构局部失稳,造成工程事故。在转体施工稳定性研究的基础上,主要考虑风速对桥梁面外稳定系数的影响,以某铁路跨越既有铁路为例,转体施工过程中以桥梁的面外稳定系数为控制目标,通过稳定性理论分析,建立了转体过程中转速与面外稳定系数之间的方程以及风速与面外稳定系数之间的方程,分析了转速与风速对转动过程中桥梁稳定性的影响。结果表明:转速较小时,风速大小对转体系统稳定性影响较大;转速较大时,风速大小对转体系统稳定性影响较小;当风速较小时,急停时间对转体系统稳定性影响较大,风速较大时,急停时间对转体系统稳定性影响较小;为保证转体施工过程的安全性,在风速小于8m/s转动加速度不应大于0.1°/s²;风速为8~18m/s时,转速对面外稳定系数k₂影响较小,在保证安全的前提下可以控制转速在0.01rad/s以内。

关键词: 曲线桥, 转体法, 稳定性