粉房湾长江大桥主桥结构设计

Structural Design of Main Bridge of Fenfangwan Changjiang River Bridge

重庆江津粉房湾长江大桥主桥为(60.5+156+464+156+60.5)m双塔双索面半飘浮体系公轨两用钢桁梁斜拉桥,桥塔为曲线宝塔形,部分预应力钢筋混凝土结构,塔柱全高188.30m,中间设置3道横梁,采用钢筋混凝土承台和大直径(Φ3.0m)钻孔灌注桩基础。钢桁梁采用空间三角形桁式,正交异性桥面板,上层为公路桥面,双向6车道,下层为双线轨道交通桥面。斜拉索每索位布置2根拉索代替常规的1根拉索,以降低强大索力对塔柱产生的应力集中影响,同时具有不中断轨道交通换索的可行性。

The main bridge of Fenfangwan Changjiang River Bridge in Jiangjin,Chongqing is a light rail-cum-road semi-floating system steel truss girder cable-stayed bridge with double pylons,double cable planes and with span arrangement（60.5＋156＋464＋156＋60.5） m.The pylons of the bridge are the pagoda-shape curved partial prestressed concrete structures.The total height of the columns of a pylon is 188.30 m and in between the pylon columns,three cross beams are arranged.The foundation of the pylon is formed by the large diameter（3.0 m） bored piles plus reinforced concrete pile cap.The steel truss girder employs the spatial triangular truss topped with orthotropic deck plates.On the upper deck of the truss girder,the dual three-lane roadway is arranged while on the lower deck,the double-track light rail transit is laid.At each point of the stay cables,a pair of two cables is used to replace a single cable as is the normal case of cable-stayed bridges so as to reduce the influences of the concentrated stress from the strong cable forces on the pylon columns,which at the same time makes it feasible for future replacement of the stay cables without interruption of the light rail traffic.