Temperature Analysis of Single-Box Three-Cell Concrete Box Girder Considering Actual Wind Field

Abstract

Current research on single-box multi-compartment concrete box girders ignores the effect of the wind field on the temperature distribution of the box girder. Incoming wind has a significant effect on the convective thermal transfer coefficient on the surface of the box girder structure, and affects the temperature field analysis accuracy. In this paper, a single-box three-cell concrete box girder is taken as the research object; the temperature field model of the world’s largest single-box three-cell concrete box girder is established, and a dot matrix temperature field modeling test is conducted. Based on the wind field distribution characteristics of the single-box three-cell concrete box girder, more accurate convective thermal transfer boundary conditions were determined. The model’s temperature field and gradient distributions were validated and compared with traditional methods that neglect wind effects. The results showed a 71% reduction in root mean square error and a 69% reduction in mean absolute error, with the vertical temperature gradient in the web closer to actual conditions. To solve the difficult problem of determining the thermal boundary conditions at different cross sections, a wind speed reduction coefficient model of a concrete box girder with variable cross section and a single-box and three rooms is established, which is linearly related to the aspect ratio of the box girder. The influence of incoming wind speed and box girder geometry on the wind speed reduction coefficient at different cross sections of the bridge is quantitatively evaluated, and the empirical formula for the convective heat transfer coefficient used in previous research is improved.