武汉杨泗港长江大桥主桥加劲梁架设施工技术

Construction Techniques for Stiffening Girder of Main Bridge of Yangsigang Changjiang River Bridge in Wuhan

武汉杨泗港长江大桥主桥为主跨1700 m的单跨双层公路悬索桥,加劲梁采用全焊接钢桁梁结构,共49个节段,其中标准梁段长36 m、宽32.5 m、桁高10 m,重约1010 t。加劲梁采用大节段制造、运输和架设总体思路施工。利用900 t液压提升式缆载吊机由跨中向两侧架设加劲梁,其中,无吊索区2个梁段采用单台缆载吊机“荡移法”架设,其余47个梁段均采用2台缆载吊机“抬吊”架设。加劲梁架设时,先利用2台缆载吊机架设跨中区域7个梁段,再利用4台缆载吊机对称架设剩余42个梁段,最后在塔柱两侧采用“预偏法”合龙。在加劲梁架设过程中,采用了“节段间临时连接+部分配重”的方案施工;并根据加劲梁架设顺序对航道布置进行了2个阶段的动态调整。

The main bridge of Yangsigang Changjiang River Bridge in Wuhan is a single-span double-deck highway suspension bridge with a main span of 1700 m.The stiffening girder for the main bridge consists of all-welded steel truss structure having 49 segments,and a standard segment measures 36 m(length)×32.5 m(width)×10 m(truss height)and weights about 1010 t.Large-sized segments are prepared to facilitate the fabrication,transportation and erection in the construction of stiffening girders.The 900 t hydraulic lifting cable cranes are employed in erecting the stiffening girders from mid-span to two sides.During the construction,one 900 t cable crane is adopted to erect the two segments located in non-sling area to the designed position by a swing method,and two 900 t cable cranes are adopted to erect the other 47 segments by a lifting method.Meanwhile,two cable cranes are deployed for erection of the seven mid-span segments,and four cable cranes are deployed for erection of the rest 42 symmetrical segments.Finally,the pre-biased method is used for steel truss closure on both sides of the tower column.Temporary connection between segments plus partial counterweighting method was invented by engineers in the process of erecting the stiffening girders.Moreover,the dynamic adjustment of the navigation channel layout was carried out according to the erection sequence of stiffening girders.