西郊大桥悬臂浇筑施工线形及应力控制

Alignment and Stress Control of Cantilever Casting Construction of Xijiao Bridge

连续刚构桥采用挂篮悬臂浇筑施工需经历长期复杂的过程及结构体系的转换,为保证成桥线形和结构受力满足设计要求,必须在桥梁施工过程中对结构的线形和内力进行有效监测与控制。以西郊大桥为工程背景,采用Midas Civil建立了全桥的数值分析模型,并构建了桥梁线形和应力监控体系,对施工全过程进行分析。结果表明,锚下张拉控制应力、温度场变化、混凝土容重及收缩徐变为主要状态因素,施工中应加强对这些因素的控制。采用的监控手段确保了合龙口相对高差、桥梁轴线横向偏差、主梁变形及应力满足设计要求。

Continuous rigid frame bridge cantilever casting with a hanging basket requires a long and complicated process and structural system conversion.In order to ensure that the bridge alignment and structural stress meet the design requirements,it is necessary to effectively monitor and control the alignment and internal force of the structure during the bridge construction process.Taking the Xijiao Bridge as the engineering background,this paper used Midas Civil to establish a numerical analysis model of the entire bridge,and established a bridge alignment and stress monitoring system to analyze the entire construction process.The results show that the tension control stress,temperature field change,concrete bulk density and shrinkage under the anchor become the main state factors,and construction control of these factors should be strengthened.The monitoring methods adopted ensure that the relative height difference,bridge axis lateral deviation,main beam deformation and stress of the closing opening meet the design requirements.