芜湖长江公铁大桥强箱弱桁组合结构钢主梁悬臂架设技术

Cantilever Erection Technique for Steel Main Girder of Strong Box and Weak Truss Composite Structure of Wuhu Yangtze River Rail-cum-Road Bridge

商合杭高铁芜湖长江公铁大桥为世界首座高低矮塔公铁两用斜拉桥。因跨度大、重载线路多、塔矮索平等因素,大桥采用了强箱弱桁组合结构钢主梁。根据主梁结构特点和安装难点,提出除主塔墩顶节段外,其余节段采用悬臂架设的总体安装方案。区别于同类常规的悬臂架设技术,芜湖长江公铁大桥钢主梁安装采用800 t变幅式架梁吊机站位于上层公路梁、先直接提升安装铁路梁后变幅安装公路梁的分层架设技术。该悬臂架设技术充分利用主梁的承载能力,最大程度减小吊机规模,提高架梁效率,缩短架梁时间,是适宜强箱弱桁组合结构钢主梁的悬臂架设技术。

Wuhu Yangtze River Rail-cum-Road Bridge of Shangqiu-Hefei-Hangzhou HSR is the world’s first rail-cum-road cable-stayed bridge with asymmetrical pylons. Due to factors such as large span, heavy-haul transport, low pylons, small inclined angles of cables, the strong-box and weak-truss composite structure for the steel main girder is adopted for the bridge. According to the structural characteristics and installation difficulties of the main girder, the overall installation scheme of cantilever erection is proposed for the segments except those on the tops of the main pylon. Different from similar conventional cantilever erection technique, the 800 t luffing girder erection crane, located at the upper highway girder, is adopted for the installation of the steel main girder of Wuhu Yangtze River Rail-cum-Road Bridge, and the layered erection technique is applied for the installation of the railway girder by direct lifting before installation of the highway girder under luffing control.This cantilever erection technique makes full use of the bearing capacity of the main girder and minimizes the scale of the crane operation, improving the efficiency of the girder erection and shortening the girder erection time. It is the most suitable cantilever erection technique for steel main girder of strong-box and weak-truss composite structure.