三跨梁拱组合体系拱桥上部结构拼装施工关键技术

Key Techniques in Assembling Superstructure of Three-span Beam-Arch Composite Arch Bridge

阜阳市向阳路颍河大桥主桥为(47+148+47)m三跨下承式梁拱组合体系拱桥,采用支架法先梁后拱架设。采用2台超大型跨桥龙门吊进行上部钢结构拼装,可以有效控制超宽桥面的拼装线形:中跨支架预留2孔宽度达32.3 m的临时通航孔,既满足了施工需要,又保证了施工期间的正常通航;主墩墩顶区搭设胎架进行单元件现场散拼,有利于减少钢材的工作应力集中及提高拼装精度;中跨先拼装两侧钢纵梁并预留焊缝收缩量,保证了钢纵梁间大横隔板的安装栓孔重合度及桥面宽度;采用大节段拼装及三维空间坐标定位法,解决了空间曲面构造的X形风撑高空拼装的难题。

The main bridge of Yinghe bridge in Fuyang city with three-span of（ 47＋148＋47） m is a through beamarch composite arch bridge,which is constructed by using the scaffold method to erect arch after the construction of beam.In order to effectively control the assembling alignment of super-wide deck,two large span gantry cranes were adopted to assemble the superstructure.The two-hole width of 32. 3 m temporary navigable hole of midspan was reserved,which met the demands of construction,and guaranteed the normal navigation during construction. The tyre frame was erected on the top of the main pier to assemble the unit,which reduced the stress concentration of the steel and improved the precision of the assembly.In order to ensure the width of deck and the recombination of the bolt holes of diaphragms between the steel longitudinal beams,the steel longitudinal beams on both sides of midspan were assembled firstly and the weld shrinkage was reserved.The difficult problem of X-type of wind brace in the high-altitude assembly is solved by using the large segment assembly method and three-dimensional space coordinate positioning method.