异形斜塔斜拉桥桥塔设计关键技术  

Key Pylon Design Techniques for Irregular Cable-Stayed Bridge with an Inclined Pylon

作　　者：林杰 许波[1] 欧阳泽卉 LIN Jie;XU Bo;OUYANG Ze-hui(CCCC Second Highway Consultants Co.,Ltd.,Wuhan 430056,China)

机构地区：[1]中交第二公路勘察设计研究院有限公司,湖北武汉430056

出　　处：《桥梁建设》2023年第S01期111-118,共8页Bridge Construction

基　　金：国家重点基础研究发展计划(973计划)项目(2015CB057701)。

摘　　要：峡口香溪河大桥主桥为(90+238)m的独柱混凝土斜塔混合梁斜拉桥,主跨为扁平钢箱梁、边跨为单箱双室混凝土梁。桥塔顺桥向为一字形、横桥向为钻石形,仿琵琶设计,塔高126 m,向岸侧倾斜,与竖直面成10°夹角,塔柱采用C50混凝土,分为上、中、下塔柱。成桥后中塔柱截面内、外缘应力分布不均,通过在塔柱底部装饰钢管内设置横向体外索,并施加8000 kN的预紧力改善中塔柱应力。斜塔中塔柱施工设计时,为减小施工中塔柱的累积弯矩,提出斜塔顺桥向顶推施工方案,并设置3道斜塔支撑。通过比较2组顶推力的作用效果,3道支撑选择荷载较小的顶推力(1~3号支撑顶推力分别为2400,3000,3300 kN),既能保证中塔柱施工安全,又能兼顾支撑受力。上塔柱施工时,选择在9号钢箱梁完成斜拉索第二次张拉后拆除支撑,以避免斜塔支撑受力太大;支撑拆除后主跨钢梁“上翘”、桥塔向岸侧“偏移”,结构位移较大,为使各拆除步骤下塔顶结构位移偏差最小,位移尽量“均匀”,按3号支撑→2号支撑→1号支撑的顺序拆除支撑。The main bridge of Xiakou Xiangxi River Bridge is a hybrid girder cable-stayed bridge with an inclined concrete pylon that creates two spans of 90 m and 238 m.The superstructure in the main span consists of flat steel box girders,while the superstructure in the side span is composed of two-cell concrete box girders.The pylon is"-"shaped along bridge length,but diamond-shaped along bridge width,resembling a Pipa(a traditional Chinese musical instrument).The pylon rises 126 m,and inclines towards the river bank,forming a 10°angle with the vertical plane.The pylon is made of C50 concrete and consists of upper,intermediate and lower columns.After completion of the bridge,the stresses in the cross-section of the intermediate column and edges were not uniformly distributed,to address this issue,transverse external prestressing tendons were added to the ornamental steel tubes in the pylon base,and a 8000 kN pre-tightening force was applied to improve the stress condition of the intermediate pylon column.To reduce the accumulated bending moment in the intermediate pylon column during construction,three struts were installed to support the inclined pylon,through which forces could be applied to push the pylon along the bridge length,and the effect of two groups of pushing forces were compared,in accordance with the results,smaller pushing forces were determined for the three struts,specifically 2400,3000,3300 kN for the No.1,No.2 and No.3 struts,respectively,which could not only ensure construction safety of the intermediate pylon column,but also serve as supports and load bearing components.During the construction of the upper pylon column,the struts were dismantled after the installation of the steel box girder No.9 and the second-time tensioning of the stay cables,to alleviate the inclined pylon from excessive loading.After the demolition of struts,the steel box girders in the main span warped upward,the pylon displaced towards the river bank,and the displacement of the structure was great.To minimize the pylon-top di

关 键 词：斜拉桥 钻石形斜塔 预紧力 斜塔支撑 顶推施工 支撑拆除 桥梁设计 

分 类 号：U448.27[建筑科学—桥梁与隧道工程] U442.5[交通运输工程—道路与铁道工程]