悬索桥用于铁路桥梁的可行性分析

Feasibility Analysis of Applying of Suspension Bridge Type to Railway Bridges

为探讨悬索桥是否适用于我国的铁路桥梁,从结构受力、抗风与抗震、结构刚度、梁端转角、车桥耦合振动分析、轨道几何形位评价几方面验证了其可行性。针对我国铁路桥梁的特征提出采用悬索桥的相关建议:(1)主缆直径不超过1.3m,可采取的措施包括主缆取合适的强度安全系数并配合使用防腐除湿系统、采用超高强度钢丝、采用多根主缆;(2)桥塔及锚碇与公路悬索桥受力机理相同,按规范设计;(3)加劲梁疲劳应力幅较大,应处理好疲劳设计;(4)抗风与抗震计算应满足规范要求,必要时需通过风洞试验验证以及设置阻尼器使地震与快速荷载作用下伸缩装置参数在正常范围内;(5)结构刚度可参考建议标准,梁端转角应满足规范要求;(6)车桥耦合振动分析、轨道几何形位评价应满足列车运行的轨道平顺性要求。

To investigate if the suspension bridge type is applicable to the railway bridges in China,the feasibility of applying of the bridge type to the railway bridges is verified from several aspects of the structural force conditions,wind and seismic resistance,structural stiffness,girder end rotation angles,train and bridge coupling vibration analysis as well as the track geometric shape and position evaluation.In the light of the characteristics of the railway bridges in China,the following relevant proposals for applying of the suspension bridge type are put forward:(1) The diameter of the main cables should not be greater than 1.3m.The measures that can be taken are that the appropriate strength safety coefficients for the cables should be selected and at the same time,the anti-corrosion dehumidification system,the ultra-high strength steel wires and the multiple cables should be used.(2) The mechanical mechanism of the towers and anchorages of the railway suspension bridges is the same with that of the highway suspension bridges and the towers and anchorages should be designed,following the codes.(3) The fatigue stress ranges of the stiffening girders of the railway suspension bridges are normally great and the fatigue design of the girders should be well dealt with.(4) The wind and seismic resistance calculation should satisfy the relevant requirements in the codes and wherever necessary,the wind tunnel tests should be made in order to check the wind resistance and the dampers should be arranged to ensure that the parameters of the expansion devices can work well in the normal ranges under the earthquake and the rapid load action.(5) The structural stiffness can be referred to the criteria as proposed in this paper and the girder end rotation angles should satisfy the requirements in the codes.(6) The train and bridge coupling vibration analysis and the track geometric shape and position evaluation should satisfy the smoothness requirements for the tracks on which the trains will travel.