大跨度钢箱梁斜拉桥中跨合龙关键技术

Key Technology of Medium Span Closure for Long-span Steel Box Girder Cable-stayed Bridge

以4座主跨超过400 m的钢箱梁斜拉桥中跨合龙控制为背景,对大跨度钢箱梁斜拉桥中跨合龙的2种方法进行对比分析,对合龙各主要工序的关键技术进行研究。提出了合龙段配切长度的计算公式和合龙口宽度连续观测的测点布置方式。建议:在调整好合龙口姿态后可不加压重,也可不采用临时劲性骨架锁定;采用无线采集设备采集合龙口结构的温度场,用激光测距仪测量合龙口宽度以提高观测效率和安全性;在悬臂施工阶段关注梁长累计误差并通过调整后续梁段的制造长度消除之。

Based on the control of medium span closure of four steel box girder cable-stayed bridges whose main span is more than 400 m,two closure methods of medium span closure of long-span steel box girder cable-stayed bridges were compared and analyzed,and the key technologies of each main process of closure were studied.The formula for calculating the matching and cutting length of closure section and the arrangement of measuring points for continuous observation of closure width were presented.It is suggested that after adjusting the closure posture,the closure weight or temporary rigidity skeleton locking should not be used.The structure temperature field of the closure should be collected by wireless acquisition equipment,and the width of the closure should be measured by laser rangefinder to improve the observation efficiency and safety.The cumulative error of the girder length should be paid attention to during the cantilever construction stage,which should be eliminated by adjusting the manufacturing length of subsequent girder segments.