快速铁路大跨连续梁桥施工监控及控制体系研究

摘要

为保障特大跨度预应力连续梁桥结构安全、几何线形平顺,成桥各安全控制指标满足设计要求,以新建怀邵衡铁路沅江特大桥(60+ 100+60)m预应力混凝土连续梁桥为工程依托,根据理论计算及结构特点,构建快速铁路大跨连续梁监控体系,重点进行参数敏感性分析,建立线形及应力监控系统,数据计算、分析和处理方法.理论研究及工程实践表明:混凝土容重和预应力效应为影响线形和内力的关键因素,其次是混凝土弹模和收缩徐变,施工中需加强对这些参数的控制及识别;采用的计算方法和监控手段确保了该桥主梁线形平顺和受力安全,合龙口精度、主梁线形和应力误差均满足规范要求,结构安全可控、工作状态良好.%In order to ensure the safety and geometry of long-span prestressed continuous beam bridge and the compliance of the control indicators of the finished bridge with design requirements,the (60+100+ 60) m prestressed continuous beam bridge of Yuanjiang Extra Large Bridge on Huaihua-Shaoyang-Hengyang Railway is taken for case-study.The construction control system of super long-span continuous beam bridge of fast-speed railway is established according to the theoretical calculation and structure features with focuses on the sensitivity analysis of parameters,the establishment of geometric linear and stress monitoring system,and the methods of data calculation,analysis and processing.Theoretical research and engineering practice show that concrete bulk density and prestressing are the key factors affecting the geometric linear and internal force,followed by the concrete elastic modulus and creep and shrinkage.The control and identification of these parameters need to be strengthened during construction.The calculation and construction control methods employed ensure the geometric linear smoothness and safe girder stress,and maintain the precision of closure gap profile and the error of geometric linear and stress in compliance with specifications,and the structure is thus well controlled and in good working condition.