变截面单箱双室连续刚构特大桥施工技术研究

Research on construction technology of continuous rigid frame large bridge with variable section single box and two chambers

乌鲁木齐绕城高速公路(西线)工程为双向八车道公路,是我国西部高速公路网的重要组成部分,主线长93.616km,设计时速100km/h。其中,头屯河连接线特大桥为乌鲁木齐绕城高速公路(西线)工程的三座特大桥之一。头屯河连接线特大桥分为主桥、东引桥和西引桥三部分:西引桥上部结构为预制小箱梁,共5联,桥跨布置4×(3×40)+4×40m。东引桥上部结构为钢-混组合梁,共5联,桥跨布置4×(3×60)+3×45m。头屯河连接线特大桥主桥为本项目控制性工程,连续刚构梁体为单箱双室,变高度、变截面结构,采用菱形挂篮悬臂现浇法施工。上部结构连续刚构0#块采用托架施工,分两次浇筑成形。墩身预埋插销盒,通过安装牛腿托架作为0#块支撑体系,牛腿托架采用三角形托架,在横桥向两侧,每侧安装6片三角形托架,托架组合成为0#块施工支架受力系统,保证施工安全要求。连续刚构梁1~16节段采用菱形挂篮施工,0#块施工完成后,拼装挂篮,在挂篮底板采用预制块完成菱形挂篮预压,采集预压相关数据作为后期施工参考依据。悬臂两端节段同时施工,保持悬臂对称平衡,直至第16节段施工完成。

The main line of Urumqi Ring Expressway(West Line)project is 93.616 kilometers long,designed according to the standard of two-way eight-lane expressway,the design speed is 100km/h,and the width of the roadbed is 41m.Among them,the Tou Tunhe connection super bridge is one of the three super Bridges of Urumqi Ring Expressway(West Line)project.The super bridge is divided into three parts:the main bridge,the east approach bridge and the West approach bridge:the upper structure of the west approach bridge is prefabricated small box girder,a total of 5 pairs,and the bridge span arrangement is 4×(3×40)+4×40m.The upper structure of the east approach bridge is composed of steel-mixed composite beams with a total of 5 connections,and the bridge span arrangement is 4×(3×60)+3×45m.The main bridge of Toutun River connecting line is the control project of this project.The continuous rigid frame beam body is single box and double chamber,and the structure is variable height and cross-section.It is constructed by rhomboid hanging basket cantilever cast-in-place method.The continuous rigid frame 0#block of the superstructure is constructed by bracket and is divided into two pours.Pier embedded bolt box,through the installation of the bull leg bracket as a 0#block support system,the bull leg bracket uses a triangle bracket,on both sides of the cross bridge,each side of the installation of 6 pieces of triangle bracket,bracket combination into a 0#block construction bracket stress system to ensure construction safety requirements.Diamond-shaped hanging basket is used for the construction of 1-16 sections of continuous rigid frame beams.After the completion of the construction of 0#blocks,the hanging basket is assembled,and prepressure of diamond shaped hanging basket is completed by prefabricated blocks on the bottom plate of the hanging basket.The relevant data of prepressure is collected as a reference basis for later construction.The two end sections of the cantilever are constructed at the same time to maintain the symmetrical balance of the cantilever until the construction of section 16 is completed.