大跨梁桥悬臂施工期间温度效应监测与分析

Monitoring and analysis of temperature effect during cantilever construction of long span girder bridge

分析大型桥梁施工期间温度对主梁线形的影响.以主梁悬臂施工中的某大桥为工程依托,进行温度场实验.同步测量箱梁多点的温度和主梁各测点的挠度,将温度场实验总结出的箱梁的温度梯度作用于T构的主梁,将挠度的计算结果与实测结果进行比较.发现理论计算中T构两侧对称测点的挠度基本相等,而实际测量中则出现了不对称下挠.温度梯度会使悬臂施工中的主梁产生较大的挠度,临时支墩温度场会引起T构两侧悬臂的不对称下挠.

The influence of temperature appearing during the construction of large-scale bridges on the linear of their main girder was analyzed.Taking the main girder cantilever of a large-scale bridge in its construction as an illustrative engineering,the temperature field experiment was performed.The temperature of multiple points in the box girder and the deflection of each corresponding point of the main girder was synchronously measured.The temperature gradient in the box girder derived from the temperature field experiment was applied to the main girder with T-structure,and then the analytical calculation result of the deflection and its corresponding measuring result were compared.It was found that the calculated deflection of the symmetric points at both sides of the T-structure was basically equal to each other,but the measured deflection was not symmetrical.It could be concluded that temperature gradient would make the girder make larger downward deflection during cantilever construction,and the temperature gradient in a temporary pier would cause the unsymmetrical downward deflection at both sides of the T-structure.