摘要
南美某城市轨道交通建设项目位于主城区,全长23.86 km,全线共计744跨高架桥,其中631跨为U形混凝土节段梁,采用架桥机整跨拼装施工。某架桥机架设首跨高架桥时,末端节段因空间受限出现难以落梁难题,从架桥机结构设计适应性、施工测量误差控制以及节段梁长度累积偏差方面进行分析,主要原因为架桥机结构设计考虑不充分、施工测量控制与节段梁尺寸精度管理不足。基于分析原因及结构特点,提出梁体提升与架桥机调整2个方案,通过施工可行性、安全性及其对桥梁结构质量的影响等方面进行比选,最终选定架桥机调整方案;进一步对架桥机立于承台支架、架桥机立于盖梁支架2种方案进行地基承载力及钢管支架、盖梁、架桥机支腿横梁等关键结构受力验算,确定采用架桥机立于盖梁支架方案。采用该方案末端节段在1 cm误差内成功落梁,有效解决了末端节段落梁难题。
A rail transit construction project in a South American city is located in the urban core area,with a total length of 23.86 km and 744 spans of elevated bridges,including 631 spans of U-shaped precast segmental girders erected using a full-span launching gantry method.During the erection of the first span by a launching gantry,the terminal segment could not be successfully placed due to spatial constraints.An in-depth analysis was conducted from the perspectives of launching gantry structural adaptability,construction surveying error control,and cumulative dimensional deviation of segmental girders.The root causes were identified as insufficient consideration in the launching gantry structural design,inadequate measurement control,and segment fabrication accuracy.Based on the analysis and structural characteristics,two mitigation schemes—girder lifting and launching gantry adjustment—were proposed.A comparative evaluation was carried out considering constructability,safety,and potential impact on the structural integrity of the bridge.The launching gantry adjustment scheme was ultimately selected.Further structural verification was performed for two sub-schemes:launching gantry supported on pile cap-mounted brackets(scheme 1),and launching gantry supported on pier cap brackets(scheme 2).Foundation bearing capacity,steel pipe supports,pier caps,and gantry support beams were all checked.The final solution adopted was the launching gantry supported on pier cap brackets(scheme 2).With this approach,the terminal segment was successfully placed within a tolerance of 1 cm,effectively resolving the girder placement obstruction issue at the span end.
作者
王闯
肖林
徐文杰
张成威
WANG Chuang;XIAO Lin;XU Wenjie;ZHANG Chengwei(CCCC Second Harbor Engineering Co.,Ltd.,Wuhan 430040,China;Key Laboratory of Large-Span Construction Technology,Wuhan 430040,China)
出处
《世界桥梁》
北大核心
2025年第6期8-15,共8页
World Bridges
关键词
城市高架桥
U形节段梁
节段拼装
架桥机
落梁
施工方案
稳定性
有限元法
urban elevated bridge
U-shaped segmental girder
segmental assembly
launching gantry
girder placement
construction scheme
stability
finite element method
