大跨度钢桁梁廊道桥顶推施工关键技术研究

Research on Key Technology of Jacking Construction of Long Span Steel Truss Gallery Bridge

齐齐哈尔热网跨嫩江廊道桥为大跨度下承式钢桁梁结构,受工期紧、河道通航和泄洪等因素的制约,拟采用岸边支架组拼加步履式多点同步顶推的施工方法。以该工程为依托,首先介绍了工程概况和方案比选情况,分析了施工中存在的难点。然后阐述了岸边组拼支架平台的布置原则,顶推滑移系统设置和顶推设备配置,并利用MIDAS/Civil有限元软件对钢桁梁顶推施工中构件的内力及变形进行了计算。最后,对顶推同步性、精度和支反力控制,实时应力、应变监测和纠偏等控制要点进行了深入分析。现场实施效果表明:岸边支架组拼加步履式多点同步顶推架设廊道桥施工方案安全可靠,具有可直接顶推、节约成本、节省工期、减少水中施工风险等优点。

The corridor bridge of the Qiqihar Heating Network across the Nenjiang River is a long-span through steel truss girder structure.Due to such constraints as tight construction period,river navigation,flood discharge,etc.,it is proposed to adopt a construction method of shore bracket assembly and walking-type incremental launching construction by multipoint jacking.Based on the project,the general situation of the project and the scheme comparison were introduced first,and the difficulties existing in the construction were analyzed.Then,the layout principle of the shore assembly support platform,the setting of the pushing-slip system,and the configuration of pushing equipment were expounded,and the internal force and deformation of the steel girder in jacking construction were calculated by using Midas/Civil finite element software.Finally,the control points of pushing synchronization,precision,support reaction control,real-time stress and strain monitoring,and deviation correction were analyzed.The field implementation results show that the construction scheme of the corridor bridge erection by shore bracket assembly and walking type incremental launching construction by multipoint jacking is safe and reliable,having such advantages as direct jacking,cost saving,construction period saving,and water construction risk reduction.