赤壁长江公路大桥钢锚梁索塔锚固结构优化设计  

Optimization Design of Steel Anchor Beams Used as Cable-Pylon Anchorage Structure for Chibi Changjiang River Highway Bridge

作　　者：张德平[1] 徐伟[1] 黄细军[1] 杜萍[1] ZHANG De-ping;XU Wei;HUANG Xi-jun;DU Ping(China Railway Major Bridge Reconnaissance&Design Institute Co.,Ltd.,Wuhan 430056,China)

机构地区：[1]中铁大桥勘测设计院集团有限公司

出　　处：《世界桥梁》2019年第5期12-16,共5页World Bridges

摘　　要：赤壁长江公路大桥主桥为主跨720m的结合梁斜拉桥,9~29号斜拉索采用钢锚梁索塔锚固体系。钢锚梁与钢牛腿最初设计采用张拉后固结连接,设计分析发现后期更换斜拉索时施工复杂,断索时固结连接受力较大。优化设计为在钢锚梁底板增设顺桥向限位钢板,限位钢板与钢牛腿顶板侧面磨光顶紧,即张拉后顶紧式连接;钢锚梁与钢牛腿之间采用普通螺栓栓合。通过优化,换索时可直接对称放松旧索、更换新索、再对称张拉新索,断索后斜拉索水平力通过限位钢板以压力的形式传递至塔壁。采用有限元软件建立该桥索塔锚固区索力最大节段模型进行计算,得到优化方案塔壁在换索工况下不受力、在断索工况下外侧受拉,规避了原方案塔壁内侧受拉,在塔壁外侧配置适量预应力后,可满足受力要求。The main bridge of Chibi Changjiang River Highway Bridge is a composite girder cable-stayed bridge with a main span of 720 m.The stay cables No.9 to No.29 are anchored to the pylons via steel anchor beams.In the preliminary design,the steel anchor beams and steel brackets are fixed together by tensioning prestressed tendons,but the replacement of the stay cables would be difficult during the operation period,and the fixed connections have to bear great force when the stay cables are broken.Steel stopper plates are added to the base plate of the steel anchor beam along the bridge length to optimize the anchorage structure.The steel stopper plate is laterally polished to closely attach the top plates of the steel brackets,which is a kind of tightly touched connection after the tensioning of prestressing tendons.The steel anchor beams and steel brackets are linked by common bolts.After optimization,the original stay cables can be symmetrically relaxed and replaced,and the new stay cables are symmetrically tensioned.When a stay cable is broken,its horizontal force will be transferred to the pylon walls through the steel stopper plates in the form of compressive force.The finite element model of the section with maximum stay cable force in the cable-pylon anchorage zone was established for calculation.The results show that in the optimized scheme,the pylon walls do not bear force during the stay cable replacement,but the outer side of the pylon walls was in the tensile state,rectifying the drawback of the original scheme,in which the inner side of the pylon walls was in the tensile state.Adding proper amount of prestressing tendons to the outer side of the pylon walls can make the load bearing condition meet the requirements.

关 键 词：斜拉桥 索塔锚固结构 钢锚梁 张拉后固结连接 换索 断索 优化设计 

分 类 号：U448.27[建筑科学—桥梁与隧道工程] U443.38[交通运输工程—道路与铁道工程]