呼准铁路黄河特大桥主桥设计

Design of Main Bridge of Huhehaote-Zhungeer Railway Huanghe River Bridge

呼准铁路黄河特大桥主桥为(98+5×168+98)m预应力混凝土刚构—连续组合箱梁桥。主梁采用C55混凝土单箱单室变截面箱梁,三向预应力体系,在箱梁内预留体外预应力钢束张拉构件。主墩均采用圆端形截面空心墩(中间2个桥墩与主梁固结),摩擦桩基础。为适应主梁较大的温度伸缩量,开发了大位移伸缩装置及大位移活动支座。采用MIDAS Civil软件对该桥进行静、动力分析,分析结果表明,该桥在施工及运营阶段的刚度、强度均满足规范要求,且具有良好的抗震性能。该桥采用悬臂浇筑法施工,主梁合龙顺序为先边跨后中跨。

The main bridge of the Huhehaote-Zhungeer Railway Huanghe River Bridge is a prestressed concrete hybrid bridge of rigid frame and continuous girder with span arrangement （98＋5 × 168＋98） m. The main girder of the bridge is the C55 concrete single-cell single-box girder of variable section and is arranged with the three-way prestressing system and pre-reserved with the tensioning components for external prestressing strands inside the girder. The main piers are the hollow piers of round-end sections （the two intermediate piers are rigidly fixed with the main girder） and are supported on the frictional pile foundations. To accommodate the large temperature expansion amount of the bridge, the large movement expansion joints and sliding bearings were developed and the software MIDAS Civil was used to carry out the static and dynamic analysis of the bridge. The results of the analysis indicated that the rigidity and strength of the bridge at both the construction and operation stages could meet the relevant requirements in the codes and the bridge had good seismic resistance. The bridge was constructed by the cantilever casting method and the closure sequence of the main girder was that the side spans were closed first and the central span was late.