港珠澳大桥青州航道桥主梁合龙施工技术

Construction Techniques for Closure of Main Girder of Qingzhou Ship Channel Bridge of Hong Kong-Zhuhai-Macao Bridge

港珠澳大桥青州航道桥为(110+236+458+236+110)m的斜拉-连续组合体系双塔双索面钢箱梁斜拉桥,有索区主梁采用悬臂拼装方案施工,无索区主梁采用整体吊装方案施工,两侧次边跨及中跨均设1个合龙段。为保证主梁合龙施工精度及质量,结合结构体系特点,次边跨合龙采用顶推+配切合龙的方法,按照先合龙、后张拉合龙段斜拉索的工序进行合龙施工;中跨合龙采用配切合龙的方法;在合龙施工中,采取了免压重合龙观测技术,并采取折线配切方法进行合龙段精细配切。该桥主梁合龙后,次边跨及中跨合龙口最大高差分别为6mm和1mm,轴线偏差均在5mm以内,焊缝宽度均为10~15mm。实践结果表明:该桥合龙施工技术切实可行,施工简便,合龙精度满足施工要求。

The Qingzhou Ship Channel Bridge of the Hong Kong-Zhuhai-Macao Bridge is a cable-stayed and continuous system steel box girder cable-stayed bridge with double pylons,double cable planes and with span arrangement（110＋236＋458＋236＋110）m.The main girder of the bridge in the area with the stay cables was erected by the scheme of cantilever assembling while in the area without the stay cables was erected by the scheme of integral lifting and installation.At the secondary side spans on either side and the central span,each one closure segment was arranged.To ensure the construction accuracy and quality of the closure of the main girder and in consideration of the structural characteristics of the bridge,the closure of the secondary side spans was carried out,using the pushing＋match cutting method and in the sequence of closing the spans first and tensioning the stay cables of the closure segments then.The closure of the central span was carried out,using the match cutting method and in the closure construction of the span,the closure observation technique of not using the counterweight was used and the closure segment of the span was fine cut,using the kinked line match cutting method.After the closure of the main girder,the maximum height differences of the closure gaps of the secondary side spans and the central span were respectively 6 mm and 1 mm,the axial line deviation differences were within 5 mm and the welding joint width was all 10~15 mm.Practice proves that the construction techniques for the closure of the bridge are practical and feasible,the construction is simple and convenient and the closure accuracy can satisfy the construction requirements.