既有铁路桥钢桁梁更换为钢箱梁施工关键技术

某铁路黄河特大桥为24×48 m上承式钢桁梁桥,建于1969年,因长期服役,梁体安全储备下降,现采用明桥面钢箱梁替换既有钢桁梁.换梁施工采用拖拉法,设置拼装支架、拖拉反力支架、跨线龙门吊等大型临时设施,分别完成钢箱梁拼装、既有钢桁梁拆除及钢箱梁提升上桥;利用PLC同步控制系统和大吨位拖拉牵引系统进行梁体单点单向整体纵向...

Key Construction Techniques of Replacing Steel Truss Girder of an Existing Bridge with Steel Box Girder

A Huanghe River Railway Bridge is a deck-type truss bridge that was completed in 1969.After serving about half of a century,the safety reservation of the superstructure was worrying.It was decided to replace the original steel truss girder with steel box girder,and transform the original deck to be open deck.A kind of dragging method is proposed for the girder replacement.The temporary facilities,including the assembly scaffolds,dragging reaction supports and railway-crossing gantry crane were installed,which could be used to complete the tasks of girder assembly,existing steel truss demolition and lifting the steel box girders onto the deck.The PLC synchronous control system and the large-tonnage dragging traction system were utilized to carry out mono-point and one-direction longitudinal movement of the girders,and replace the existing steel truss girder with steel box girder via dragging.Before implementation,finite element software was employed to analyze the load bearing conditions of the superstructure,piers and connections of the existing trusses,and the results met the requirements.A monitoring and control system was developed to conduct real-time monitoring and guide the dragging construction.