郑州万滩黄河公铁大桥漏缆大跨度吊挂问题研究

Research on Long-Span Hanging Leaky Coaxial Cable on Zhengzhou Waitan Yellow River Highway-Railway Bridge

公铁大桥是GSM-R无线信号覆盖弱场的典型场景,需使用钢丝承力索吊挂漏缆实现信号补强,通常会增设辅助杆以减小吊挂漏缆的跨度。随着铁路工程建设对美观性、经济性的要求不断提高,直接利用桥墩实现大跨度漏缆吊挂的问题逐渐受到关注。文章以济郑高铁河南段工程的郑州万滩黄河公铁大桥为背景,建立漏缆大跨度吊挂的力学模型,研究温度、初始垂度这两个关键因素与最终垂度和设计安全系数的关系,并提出一种钢丝承力索的选型方法,最终确定该工程中钢丝承力索的选型为1×19-11.0-1370-B-YB/T 5004-2012。此外,还分析了时速350 km场景下气动力对漏缆大跨度吊挂的影响。列车以时速350 km高速通过时对钢丝承力索垂度带来一定的气动力影响,但影响时间极短,实际垂度并不会发生显著变化。对设计安全系数的减小程度不高,数值仍然在3.0以上。即便在最不利的条件下,钢丝承力索的选型方案仍然安全可靠。

Highway-Railway bridge section is a typical scene where GSM-R wireless signal is in weak coverage.It is necessary to hang leaky coaxial cable with steel strand for signal enhancement.Normally,auxiliary rods are usually added in order to shorten the span of steel strand.In recent years,according to the improvement of aesthetic and economic requirements,hanging leaky coaxial cable with the piers of bridge directly is becoming an issue of concern.Based on Zhengzhou Waitan Yellow River Highway-Railway Bridge in Henan section of Jinan-Zhengzhou High-Speed Railway,this paper establishes a mechanical model of long-span hanging leaky coaxial cable,studies the relationship between the two key factors,temperature and initial sag,and final sag and design safety factor,and then proposes a selection method of steel strand.Finally,the 1×19-11.0-1370-B-YB/T 5004-2-12 steel strand is chosen.In addition,the influence of aerodynamic force under 350 km/h on long-span hanging leaky coaxial cable is also analyzed.A certain aerodynamic force may influence the sag of strand when the train passes under 350 km/h,which is very short and will not bring obvious change to the actual sag.It could not reduce the design safety coefficient so much which is still above 3.0.Even under the worst condition,the chosen plan of steel strand is still safe and reliable.