五峰山长江大桥加劲梁架设技术

连镇铁路五峰山长江大桥主桥为主跨1092 m的钢桁梁公铁两用悬索桥,加劲梁采用板桁结合钢桁梁结构,加劲梁恒载集度大(819.1 kN/m)。其中,一期恒载集度达501 kN/m;铁路桥面和公路桥面二期恒载集度分别为233.4 kN/m和84.7 kN/m。针对该桥特点,加劲梁采用整节段吊装,架设时采用不携带铁路二期恒载的方案施工。边跨加劲梁节段利用浮吊整体吊装至滑移支架上,再滑移至设计位置,连接成整体;中跨加劲梁节段采用2台900 t缆载吊机自跨中向两侧桥塔方向架设,节段间上弦设牛腿式临时铰进行铰接,待中跨80%节段吊装后再进行刚接;中跨加劲梁架设后,对边跨加劲梁整体姿态进行调整,通过顶、落梁与中跨加劲梁合龙,合龙后铺设铁路二期恒载。

Erection Technique for Stiffening Girder of Wufengshan Changjiang River Bridge

The main bridge of Wufengshan Changjiang River Bridge on Lianyungang-Zhenjiang Railway is a steel truss girder rail-cum-road suspension bridge with a main span of 1092 m.The stiffening girder is an orthotropic steel plate and steel truss composite structure,which carries heavy dead loads(819.1 kN/m),the first-stage dead load reaching up to 501 kN/m.The second-stage dead load on the railway deck and the highway deck are 233.4 kN/m and 84.7 kN/m,respectively.Given the characteristics of the bridge,the stiffening girder took form by segmental hoisting and installation method,and during the erection process,the secondary railway dead loads were not applied.The girder segments in the side spans were monolithically hoisted by floating cranes onto the scaffoldings,then slid into design position and connected with adjacent segments.The girder segments in the central span were erected by two cable cranes with a capacity of 900 t each from the midspan towards the directions of the two towers,the upper chords of adjacent segments were connected by brackets-type temporary hinges first,and after 80%of the girder segments in the central span were finished,the temporary hinge connection was changed to moment connection.Once the erection of the girder segments in the central span was completed,the overall alignment of the girder segments in the side span was adjusted through jacking and lowering for the closure connection with the central span.After the closure of the whole stiffening girder,the secondary railway dead loads were applied.