大跨径自锚式悬索桥斜拉法施工关键技术研究

Study of Key Techniques for Construction of a Long Span Self-Anchored Suspension Bridge Using Cable-Staying Method

重庆市鹅公岩轨道专用桥主桥为(50+210+600+210+50)m的双塔双索面自锚式悬索桥,全桥采用"先梁后缆"法施工,边跨加劲梁采用顶推法施工,中跨加劲梁采用先斜拉后悬索方法施工。为选择合理的斜拉桥目标线形、斜拉索索力调整方案、斜拉索拆除顺序与拆除时机等,采用MIDAS Civil软件建立自锚式悬索桥施工过程计算模型,针对各种方案下的结构特性进行模拟计算与分析评定。计算模拟结果表明:成桥后调整部分斜拉索索力,将加劲梁拉升至接近去除二期恒载的线形作为临时斜拉桥的目标线形的方案,综合效益较优;选择从跨中16号向塔侧6号斜拉索方向调整11对索的索力调整方案;吊索张拉全部完成后临时斜拉索按自上而下顺序拆除的方案更为安全合理。

The main bridge of the Egongyan Rail Transit Special Use Bridge in Chongqing City is a self-anchored suspension bridge with double towers,double cable planes and with span arrangement（50＋210＋600＋210＋50）m.The whole bridge of the bridge was constructed,using the method of erecting the stiffening girders before installing the main cables and suspenders,of which the stiffening girders of the side spans were erected,using the method of incremental launching while the stiffening girder of the central span was erected,using the method of cable-staying first and suspending late.To select the schemes of the reasonable target alignment and stay cable force adjustment and the stay cable removal sequence and time for the temporary cable-stayed bridge,the calculation model of the construction process of the self-anchored suspension bridge was established,using the software MIDAS Civil and the structural characteristics of the bridge under the different schemes were simulated,calculated,analyzed and assessed.The results show that the scheme of adjusting the forces of partial stay cables of the completed bridge and of taking the alignment that the whole stiffening girder is stayed up approximately to the that of the girder removed with the second phase dead load as the target alignment of the bridge has better comprehensive advantages.The scheme of adjusting the forces of 11 pairs of the stay cables from the cables No.16 at the midspan towards the cables No.6 close to the pylons is selected and the scheme of removing the stay cables in the sequence from the upper to the lower cables after tensioning of the whole suspenders of the bridge is considered to be safer and more reasonable.