临猗黄河大桥组合梁负弯矩区力学性能优化措施研究  

Study of Mechanical Property Optimization Measures for Composite Girder Negative Moment Zone of Linyi Huanghe River Bridge

作　　者：王彬[1,2] 刘来君 季建东[2] WANG Bin;LIU Lai-jun;JI Jian-dong(School of Highway,Chang′an University,Xi′an 710064,China;Shanxi Transportation Survey & Design Institute Co. ,Ltd. ,Taiyuan 030032,China)

机构地区：[1]长安大学公路学院,陕西西安710064 [2]山西省交通规划勘察设计院有限公司,山西太原030032

出　　处：《桥梁建设》2021年第6期85-91,共7页Bridge Construction

基　　金：山西省交通建设科技项目(2020-2-02)。

摘　　要：山西临猗黄河大桥主桥采用(112+14×128)m+(14×128+120)m连续钢箱组合梁桥,采用钢箱梁顶推到位后安装桥面板的方案施工。由于主桥联长、跨度大,为改善组合梁负弯矩区力学性能,采用MIDAS Civil 2019软件建立主桥第一联上部结构有限元模型,分别研究桥面板分批安装、支点混凝土双结合(钢箱梁上、下翼缘均结合混凝土)构造、支点升降、支点张拉体外束4种优化措施对连续组合梁负弯矩区受力性能的影响。结果表明:增大桥面板分批安装次数能明显增大跨中区域桥面板压应力;采用支点混凝土双结合构造能够降低支点负弯矩区钢箱梁下翼缘应力;采用两端到中间的顺序进行支点升降能够提高支点负弯矩区桥面板压应力储备;支点张拉体外束对负弯矩区优化效果随着混凝土收缩徐变逐渐降低。基于研究结论,该桥主桥设计采用桥面板分批安装、支点混凝土双结合构造、支点升降3种措施对负弯矩区进行优化,不采用支点张拉体外束措施。The main bridge of Linyi Huanghe River Bridge in Shanxi Province is a continuous steel box composite girder bridge that are arranged in two units,one with fifteen spans of 112 m and 14×128 m,and the other with fifteen spans of 14×128 m and 120 m.The precast concrete slabs were installed after the steel box girders were incrementally launched into position.The long continuous unit and span length pose great challenges for the construction.To improve the mechanical property of the negative bending moment zone of the composite girder,the finite element model of the superstructure in the first continuous unit of the main bridge was established by MIDAS Civil 2019.Four optimization measures to improve the mechanical property of the negative bending moment zone of the continuous composite girder were studied,including installing the precast concrete slabs in batches,double-connection of concrete slabs and steel box girders at the supports(meaning that the concrete slabs are connected with both the upper and lower flanges of the steel box girder),raising and lowering the supports,tensioning external prestressing tendons at the supports.It is shown that dividing the concrete slabs into more smaller batches for installation can increase the compressive stress in the concrete slabs in the midspan region.Connecting the concrete slabs with both the upper and lower flanges of the steel box girders can lower the stresses in the lower flanges of the steel box girders in the negative bending moment zone at the supports.Raising and lowering the supports from the two ends towards the center can enlarge the margin of compressive stress in the concrete slabs in the negative bending moment zone at the supports.The optimization effect of tensioning external prestressing tendons at the supports is gradually diminishing along with the concrete shrinkage and creep.As a result,the measure of tensioning external prestressing tendons at the supports was dismissed,and the other three measures were applied to optimize the mechanical propert

关 键 词：连续梁桥 钢箱组合梁 负弯矩区 桥面板分批安装 混凝土双结合构造 支点升降 张拉体外束 力学性能 

分 类 号：U448.216[建筑科学—桥梁与隧道工程] U441.5[交通运输工程—道路与铁道工程]