无合龙段变高度连续钢箱梁桥顶推施工关键技术研究  

Research on Key Technology of Incremental Launching Construction of Variable Height Continuous Steel Box Girder Bridge with Non-Closure Segment

作　　者：李小祥 LI Xiaoxiang(Shanghai Tongji Testing Technology Co.,Ltd.,Shanghai 200092,China)

机构地区：[1]上海同济检测技术有限公司,上海200092

出　　处：《结构工程师》2024年第1期150-157,共8页Structural Engineers

摘　　要：以某实际工程为背景,介绍了适用于大跨变高度连续钢箱梁桥在跨中不具备设置临时墩条件下的顶推施工方法以及结构内力、线形控制技术。针对主梁梁高变化大和梁底曲线的结构特点,通过主梁立面姿态旋转的方法降低顶推抄垫高度,并采用步履机顶设置转动球冠和调整楔形块的方式适应梁底曲线与顶推设备的贴合需求。针对顶推施工过程中主梁端部挠度过大、合龙口相对高差明显、悬臂根部负弯矩显著增大的问题,基于无应力状态法思想,研究采用了两侧对顶加临时扣索辅助合龙的工艺,优化了结构成桥内力状态,降低线形控制风险;并对顶推过程中钢箱梁底板局部稳定、纵向倾覆稳定性等问题进行了计算分析,提出了相应控制措施。The incremental launching construction method,along with structural internal force and geometrical alignment control technologies,applicable to a large-span variable height continuous steel box girder bridge without a temporary pier in the mid-span,is introduced based on a real project.Given the large variation in girder height,the method of rotating elevation alignment of the girder is employed to lower the pad height during the incremental launching construction process.The use of rotating spherical caps and adjustable wedge blocks is implemented to adapt to the curvature of the girder bottom.Addressing challenges such as excessive deflection at the cantilever end,relative altitude differences at the closure segment,and a significant increase in negative bending moment at the cantilever root during the incremental launching construction process,a construction technology is utilized.This technology involves incremental launching from each side span and temporary cables assisted closing,based on the unstressed state control method.The construction approach optimizes the internal force state of the bridge structure and reduces the risk associated with geometrical alignment control.This study also includes an analysis of the local stability of the steel box girder and longitudinal overturning stability,accompanied by proposed strategies.Currently,the bridge has been successfully constructed and opened to traffic.The research findings offer valuable engineering experience for similar bridge projects.

关 键 词：变高度钢箱梁 顶推施工 无合龙段 无应力状态法 临时扣索 线形控制 

分 类 号：U445.462[建筑科学—桥梁与隧道工程]