禹门口大桥边跨大节段合龙施工控制技术

Construction Control Technology for Closure of Side Span andLarge Section of Yumenkou Bridge

大跨度钢-混组合梁斜拉桥在合龙段施工过程中,存在控制精度要求高、控制难度大等问题。以一座主跨565 m的双塔双索面钢-混组合梁斜拉桥为例,针对该桥具有边跨合龙段长、合龙口高差大的特点进行边跨大节段配切合龙施工控制。为顺利合龙,首先通过建立空间梁-板组合模型,精细化模拟散件拼装过程,准确计算合龙配重;其次对上下游合龙口的主梁间距、标高、轴线偏位进行48 h联测,确定最佳合龙温度;最后确定各合龙段钢主梁的精确制造参数。实践证明:配切法对大节段合龙施工适用性较好,该桥合龙精度很高。

In the construction of closure section of long-span steel-concrete composite girder cable-stayed bridge,there are a series of problems,such as high demand of control accuracy and large control difficulty.Taking a steel-concrete composite girder cable-stayed bridge with double pylons and double cable planes with a main span of 565m as an example,the method of side span and large segment closure was applied.The sample bridge had the characteristics of long closure section of side span design and large height difference of closure mouth.For smooth closure,firstly,the spatial beam-plate combination model was established to finely simulate the assembly process of parts and accurately calculate the closure counterweight.Secondly,48h joint measurement was carried out for the spacing,elevation and axis deviation of the main girder at the upstream and downstream closure openings to determine the optimal closure temperature.Finally,the accurate manufacturing parameters of each closure section steel girder were determined.The practice shows that the matching and cutting method has good applicability to the closure construction of large section,and the closure accuracy of the proposed bridge is high.