Temperature field of long-span concrete box girder bridges in cold regions: Testing and analysis

This study conducted monitoring and analysis of the temperature field for large-span concrete box girder bridges in cold regions. The objective is in revealing the temperature response patterns of concrete box girders under cold climate and insolation conditions, improving the accuracy of the temperature field model, and realizing accurate temperature distribution prediction. Firstly, an overview of three bridges was provided. Secondly, a measurement point arrangement scheme was proposed based on the optimal interpolation fitting solution. Then, an onsite temperature field monitoring was carried out, unveiling notable variations in temperature response patterns across distinct seasons and time intervals. Specifically, the vertical and lateral temperature patterns of the box girder were identified as "C" and "M" types, respectively. Finally, numerical fitting techniques were applied, utilizing the inverse proportional function for vertical temperature gradients and the quartic polynomial function for lateral temperature gradients. The results of these fittings effectively described the patterns of temperature gradient variations. This study establishes a cornerstone for the analysis and prediction of temperature variation patterns in long-span concrete box girder bridges, offering theoretical support for the sustained operation of bridges in cold regions.