白洋长江公路大桥主桥设计

Design of Main Bridge of Baiyang Changjiang River Highway Bridge

白洋长江公路大桥主桥为主跨1 000m的双塔单跨钢桁梁悬索桥,北岸边缆跨度276m,南岸边缆跨度269m。该桥采用塔连杆+柔性中央扣支承体系,通过塔连杆的转动满足加劲梁纵向位移与转动要求。桥塔采用混凝土门形结构,北塔高142.5m,南塔高151m,基础为分离式承台+群桩基础。钢桁梁全宽36.7m,高7.5m,采用2片主桁,华伦式桁架,主桁与桥面系分离,桥面系采用钢-混组合桥面系。充分利用长江优质航道资源及桥下水深条件好的优势,钢桁梁采用30m大节段吊装。主缆采用1 860MPa锌铝合金镀层高强钢丝,吊索采用1 960MPa镀锌钢丝绳。主索鞍、散索鞍鞍体采用铸焊结合结构。主缆采用型钢锚固系统,白洋侧锚碇采用重力式嵌岩锚,宜都侧锚碇位于富水巨厚卵石层中,国内首次采用浅埋扩大基础。

The main bridge of Baiyang Changjiang River Highway Bridge is a steel truss suspension bridge with two towers and a main span of 1 000 m.The cable spans at northern and southern shore are 276 m and 269 m,respectively.The tower connecting rod+a flexible central buckle supporting system is adopted in the bridge,and the requirements of longitudinal displacement and rotation of the stiffening girder are satisfied by the rotation of the tower connecting rod.The tower with a concrete portal structure has a height of 142.5 m in the north tower and 151 m in the south tower.The foundation consists of a group of piles with separate pile cap.The full width of steel truss girder,of which two warren-type trusses are adopted,is 36.7 m and the height is 7.5 m,and the main truss and the bridge deck are separated.The bridge deck is a steel-concrete composite deck system.By taking the full advantage of high-quality fairway in Changjiang River and the deep water conditions under the bridge,the steel truss girder with a 30 m large segment is hoisted.The main cable is made of 1 860 MPa zinc-aluminum alloy coated high-strength steel wire,and the hanger is made of 1 960 MPa galvanized steel wire rope.The main cable saddle and splay saddle have a casting and welding structure.The main cable is anchored by the section steel anchorage system,anchorage on the Baiyang side is gravity rock-socketed anchorage,and anchorage on the Yidu side is located in the rich water thick cobble layer.The shallow buried spread foundation is adopted for the first time in China.