铜陵公铁两用长江大桥主桥钢梁架设方案研究

Study of Erection Schemes for Steel Girder of Main Bridge of Tongling Changjiang River Rail-cum-Road Bridge

铜陵公铁两用长江大桥主桥为630m五跨连续钢桁梁斜拉桥,采用三主桁三索面结构型式。3片主桁均由全焊桁片拼装而成。通过对备选方案的研究和比选,铜陵岸钢梁架设采用"边跨全顶推法架设+中跨悬臂法架设"方案,无为岸钢梁架设采用"边跨部分拖拉法架设+中跨悬臂法架设"方案,中跨合龙采用"桁片整体合龙"方案。在4号桥塔墩设置顶推平台和顶推装置,将铜陵岸边跨和次边跨钢梁分段安装、分次顶推至全部就位,然后将中跨钢梁悬臂架设至合龙口;在2号墩前方设置安装平台、1号墩墩顶布置拖拉装置,将无为岸边跨和部分次边跨钢梁分段安装、分次拖拉至全部就位,然后将3号墩前后两侧钢梁双悬臂架设至边跨合龙,再将剩余中跨钢梁单悬臂架设至跨中合龙口;最后吊装合龙段桁片进行中跨合龙。

The main bridge of Tongling Changjiang River Rail-cum-Road Bridge is a five-span continuous steel truss girder cable-stayed bridge with a main span of 630 m. The bridge has the structural type of three main trusses and three cable planes and the three main trusses are all assembled from the all-welded truss units. For the erection of the steel girder of the main bridge, the alternative erection schemes were studied and compared and it was determined that the girder on the Tongling side would be erected by the scheme of erecting the whole side span girder by the incrementally launching method＋erecting the central span girder by the cantilever method. The girder on the Wuwei side would be erected by the scheme of erecting part of the side span girder by the pulling method＋erecting the central span girder by the cantilever method and the central span girder would be closed by the scheme of installing the integral truss unit. At the top of Pier No. 4 of the pylon, the launching platform and launching device were arranged. The side span and secondary side span girder on the Tongling side was assembled in blocks and launched in place in times and then the central span girder was erected by the cantilever method until the girder reached the closure gap. In the front of Pier No. 2, the assembling platform was arranged and at the top of Pier No. 1, the puling device was arranged. The side span and part of the secondary side span girder on the Wuwei side was assembled in blocks, pulled in place in times and then the girder on the front and rear sides of Pier No. 3 was erected by the two-side cantilever method until the girder reached the closure gap at the side span where the girder would be closed. The rest of the central span girder was successively erected by the one-side cantilever method until the girder reached the closure gap at the midspan of the central span and finally the truss unit for the closure was lifted and installed and the central span girder was closed.