钢-混叠合梁斜拉桥塔周梁段不对称架设技术

Asymmetrical Erection Technique for Girder Sections Around Pylons of Steel-Concrete Composite Girder Cable-Stayed Bridge

珠海洪鹤大桥主航道桥为首尾串联的2座主跨500 m双塔双索面叠合梁斜拉桥,其中跨洪湾水道的主航道桥3号桥塔位于防洪大堤背水侧,受现场施工环境限制,塔周梁段无法采用常规的施工工艺进行安装。结合现场地理环境特点及实际施工需要,塔周梁段采用不对称安装工艺,即先搭设中、边跨不对称支架,利用大型履带吊进行墩顶(0号梁段)、边跨侧(S1~S3号梁段)以及中跨侧起始梁段(C1号梁段)安装,再拼装桥面吊机和提梁站,利用桥面吊机悬臂安装中跨侧后2个梁段(C2号、C3号梁段)。采用MIDAS Civil软件对不对称施工过程中塔梁受力状态进行仿真计算,结果表明结构体系安全。

The main navigational channel bridge of Honghe Bridge in Zhuhai City consists of two composite girder cable-stayed bridges that are arranged in tandem.Each of the cable-stayed bridge has two pylons and a main span of 500 m,and the stay cables are fanned out in double cable planes.The pylon No.3 of the main navigational channel bridge crossing the Hongwan Waterway is located besides the landside slope of the flood embankment,due to the limited construction space,the girder sections around the pylons could not be erected using the conventional construction techniques.To suit the site characteristics,the girder sections around the pylons were erected in an asymmetric manner.The asymmetric scaffolds in the central and side spans were first installed,on which a large crawler crane was employed to erect the pier-top girder section(girder section No.0),starter girder sections in the side span(girder sections S1-S3)and central span(girder section C1).Then,the deck crane and gantry crane were assembled,and the two subsequent girder sections(girder sections C2 and C3)in the central span were erected in cantilevers by the deck crane.The load bearing behavior of the pylons and the girder sections during the asymmetrical construction process was simulated by MIDAS Civil.The results of the numerical simulation proved that the structural system was safe.