Measurement and Simulation of Temperature Field of Concrete Box Girder in Northwest Severely Cold Area

This study evaluated the characteristics of temperature field distribution of the concrete box girder based on the middle bridge of Xiaosha River, and the effects of temperature in severely cold area were determined through experiments and finite element model (FEM) analysis. An FEM model of the concrete box girder considering the temperature field was established based on heat transfer theory to verify the accuracy of the model. Moreover, the calculation of the vertical temperature distribution and the temperature distribution along the web plate was conducted. The distribution along the through-thickness direction of the bottom plate and the temperature drop caused by cold waves was evaluated. Results suggest that the published codes and guidebooks were relevant. The effect of the most unfavorable condition of temperature load was also calculated. The result drawn from this research shows that the distribution of temperature field at the cross sections in the severely cold area differed greatly from that in the current code. However, the temperature difference in the top flange was not evident, whereas it was much larger in the bottom flange. The temperature in the web was higher than that in the top flange under solar radiation and was lower during cooling. The results of the temperature effect were much more critical than the result calculated using the vertical temperature gradient in the current code. The tensile stress produced by temperature load may cause cracks. Consequently, sufficient attention should be paid to the damage of thermal effects when calculating the concrete box girder in the northwest of the severely cold area.