沪通长江大桥112 m钢桁梁墩顶临时连接件焊接质量控制

沪通长江大桥北岸主桥中共有23跨112 m简支钢桁梁,采用"先连续后简支,悬臂拼装"的"1+1"、"2+1"和"3+1"模式进行安装架设,结构体系转换主要通过墩顶临时连接的焊接与解除来实现。因此,墩顶临时连接件的焊接质量是保证整个钢桁梁悬臂拼装安全的关键。根据112 m钢桁梁架设方案和墩顶临时连接设计特点,厘出墩顶桥位现场焊接工程控制重难点,结合工程实际做好焊接工艺评定,从焊接坡口组装、焊接顺序,到具体焊接工艺提出针对性的技术保障措施,确保墩顶临时连接件焊接质量,有力保障悬臂拼装安全顺利过墩顶,取得很好的工程效果。

Quality Control of Temporary Connector Welding on Pier Top of 112 m-steel-truss-girder of Hu-Tong Yangtze River Bridge

There are 23 spans of 112 m simply-supported steel truss girder in the north main bridge of Hu-Tong Yangtze River Bridge. The 112 m girders are erected by the cantilever assembly method of"1 +1","2+1"and"3+1",and the structure system transform is achieved by temporary welding and removal of connectors on the top of interrelated piers,which transfers the continuous beam into simply-supported beam. Therefore,the welding quality of temporary connectors is a key factor to the successful cantilever assembling. In view of the 112 m-steel-truss-girder erection plan and the design characteristics of temporary connectors on top of piers,engineering control points and difficulties of in-site welding are clarified. And according to the site conditions, welding processes are evaluated and corresponding technical measures are worked out with respect to welding groove assembling,welding sequence and specific welding techniques,which ensure welding quality and construction safety for successful cantilever assembling over the pier top.