青州航道桥边跨大节段钢箱梁组拼控制技术研究

青州航道桥边跨和连接线深水区通航孔桥采用大节段整体吊装架设方法.针对钢箱梁大节段组拼关键控制工序,研究了钢箱梁大节段焊接施工中拼装线形控制方法,分析了主要影响参数,如焊缝收缩量、温度和组拼支撑条件对拼装线形的影响;对钢箱梁组拼过程中局部受力进行研究,分析了钢箱梁支撑位置、面积和场地不均匀沉降对其局部受力的影响,确保大节段组拼线形和局部受力可控,为钢箱梁从无应力受力状态向设计成桥状态转换奠定基础.研究结果表明：焊缝收缩量为钢箱梁焊接组拼线形控制的重点,梁重偏差可通过焊缝宽度进行有效修正;超宽钢箱梁大节段拼装线形控制时应考虑组拼支撑条件的影响;钢箱梁局部受力对支撑位置敏感,在组拼过程应严格控制支撑局部沉降.

Research on Control Method of Assembly of Large Segment of Steel Box Girder in Side Span of Qingzhou Channel Bridge

The overall lifting erection method is widely used in the construction of the side plan of Qingzhou channel bridge and the non-navigation bridge in deep water district.In order to ensure the accuracy of assembly alignment,the control method of the assembly alignment of large segment of steel box girder is researched and the influence factors such as weld shrinkage,temperature and assembly supporting conditions are also analyzed.Therefore,the influence of assembly support position,size and site of its partial differential settlement on the local stress of steel girder is evaluated to make the stress state controllable and form the foundation for the conversion of steel girder from zerostress state to the design stress state.Results have shown：The weld shrinkage has a decisive influence on the control of assembly alignment and the weight deviation can be effectively corrected by weld width allowance.Also,the influence of supporting conditions should be considered in the assembly of wide steel girder.At last,it is extremely sensitive for the position of supporting condition to the local tress of steel box girder and the local settlement of support should be strictly restricted.