港珠澳大桥钢箱梁板单元制造工艺及质量控制

Manufacturing Technique for Plate Units of Steel Box Girder of Hongkong-Zhuhai-Macao Bridge and Quality Control

港珠澳大桥主体工程钢箱梁预制段全长7.154km,其中深水区非通航孔桥采用110m跨连续钢箱梁。钢箱梁主要零部件均采用精密切割或数控自动切割,单元制造采用机械化、自动化焊接装备。钢板预处理中,在220mm齿轮式辊道外加装225mm的环状抱箍,将原有的非连续点接触方式改为连续接触方式,避免钢板被划伤。顶板单元件采用单丝打底单丝盖面的焊接工艺;底板大多为板肋板单元,板肋与底板采用坡口角焊缝,环缝连接为嵌补全焊接连接;板肋单元件首先在多头板肋龙门焊接机上采用双面单丝对称施焊进行打底,然后吊运至液压反变形摇摆胎架,采用多头龙门焊机进行船位焊接;横隔板焊接中,采用焊接机器人建立模型,设定焊接参数并严格控制。各部件焊后需进行消应处理,以提高结构疲劳强度。

The overall length of the main part of Hongkong-Zhuhai-Macao Bridge with prefabricated steel box girders is 7.154 km.The Non-navigational channel bridge in the deep water area is the continuous steel box girder structure with 110m-long spans.The main components of the steel box girders are cut by precise cutting machine or automatic cutting machine,and the components in a whole unit are connected by mechanical and automatic welding equipment.During the pre-processing of steel plates,the225mm hoop reinforcement was added to externally twine around the220mm gear roller,to transform the original way of discontinuous point contacting to that of continuous contacting,so as not to scuff the steel plates.The top plates were welded by the technique of mono-wire backing welding and mono-wire cosmetic welding.The majority of the bottom plates are plate-rib units,and the plate-ribs and bottom plates were welded with groove fillet welds.And the girth weld adopts the inlaying full-weld connection.The plate-rib unit was first processed by the multi-end plate-rib gantry-type welding machine,using the technique of doublesided mono-wire symmetrical welding for the backing weld,and then hoisted and positioned to the hydraulic anti-deformation rolling jigs,using the multi-end gantry-type welding machine to do ship position welding.During the welding of diaphragms,the welding robot was used to establish model and set welding parameters,and the welding process was rigorously controlled.After welding,each component should experience stress relief treatment,aiming to improve the fatigue strength of the structure.