拱桥新型吊杆安全性及其静动力影响研究

Study of Safety of New Type Suspenders and Their Impact on Static and Dynamic Performance of Arch Bridge

为研究吊杆失效对拱桥产生的不利效应,以一座三跨连续坦拱钢桥为背景,分析带套筒螺纹连接的不锈钢短吊杆运营期断裂对桥梁整体静、动力性能的影响。通过分析该类吊杆最可能的失效模式,引入吊杆失效引起的动力放大系数指标,采用ANSYS建立桥梁整体空间模型,分析单根吊杆失效引起的吊杆应力、拱肋和主纵梁关键截面应力及结构自振特性变化。结果表明：拱跨内单根吊杆失效引起主梁竖向位移动力放大系数为1.6~2.2;次短吊杆突然失效对相邻吊杆应力影响较大;单根吊杆失效对桥梁整体静力安全和动力特性影响较小。

To study the unfavorable effect of failure of suspenders on arch bridge,a three-span continuous steel flat arch bridge is taken as the research object and the impact of failure of the in-service stainless steel short suspenders connected by sockets and threads on the global static and dynamic performance of the bridge is analyzed.Through analysis of the most possible failure modes of such type of the suspenders and introduction of the dynamic amplification factor indices caused by the failure of the suspenders into calculation,the global spatial finite element models of the bridge are established by the software ANSYS and the changes of stress in the suspenders and in the critical sections of the arch ribs and longitudinal main girder as well as the changes of natural vibration characteristics of the bridge caused by the failure of individual suspender are analyzed.The results of the analysis indicate that the dynamic amplification factors of the vertical displacement of the main girder caused by the failure of the individual suspender in the range of the arch span are 1.6~2.2.The impact of the sudden failure of the secondarily short suspenders on the stress in the adjacent suspenders is great and the impact of the failure of the individual suspender on the global static safety and dynamic performance of the bridge is small.