牂牁江特大桥上横梁制造技术

Manufacturing Technology of The Upper Beam of the Zangke River Large Bridge

带正交异性桥面板横梁制造过程中的焊接变形控制问题一直是行业难题。牂牁江特大桥上横梁为带超短正交异性桥面板的工形结构,窄长的结构形式比其他相似结构更难控制变形问题。横梁上下焊接量不均衡会导致焊接变形极难控制,且上横梁是该桥主横桁架的组成部分,与主桁、桥面板纵梁及U肋、横架腹杆间均为高强螺栓连接,对其外形尺寸和栓孔连接精度提出了更高要求。根据制造难点,本文研究了横梁腹板预拱度设置、桥面块体分步组装、倒装法组焊上横梁、整体组焊修合格后数控钻制主体孔群等制造方案。实践证明,该方案合理、可行。

Welding deformation control in the manufacturing of beams with orthotropic bridge panels has always been a difficult problem in the industry.ZangKe River Bridge was originally a structured structure with ultra-short orthotropic bridge panels.The narrow and long structure was much more difficult to control deformation than previous similar structures.The uneven welding amount between the upper and lower beams would make it extremely difficult to control the welding deformation.Moreover,the upper beam was an integral part of the main transverse truss of the bridge and was connected by high-strength bolts with the main girder,the longitudinal beam of the bridge panel,the U rib and the crosslink.According to the manufacturing difficulties,the manufacturing schemes such as pre-camber setting of beam web,step assembly of bridge floor block,flip assembly welding on beam,CNC drilling of main hole group after the whole welding is qualified、studied and determined.The scheme is reasonable and feasible through practice.