薄壁箱型梁桥日照温度场的数值计算分析

Numerical calculation and analysis of sunshine temperature field on thin walled box girder bridge

基于箱梁内空气为完全透射体,内壁混凝土表面之间仅有辐射换热和对流换热的基本假定,建立了薄壁箱型梁桥日照温度场的数学模型。根据实测环境温度分布,用平面四边形等参数单元PLANE55和表面效应单元SURF151建立了托克托准格尔黄河特大桥二维瞬态温度场的有限元模型,计算了箱梁在不同时刻的日照温度分布,并与现场的实测数据进行了比较和分析,得出如下结论:在日照作用下,箱梁顶板上下缘之间的温差最大值约在下午14∶00出现;理论计算的温度时程曲线与实测的温度时程曲线吻合较好;混凝土壁板中的温差分布,可以采用指数曲线进行拟合。

Based on the hypothesises that inner air in box girder is the full homology substance and there are only the radiation heat and convection heat transfer on the surface between the inner concrete walls, the mathematical model for sunshine temperature field of the thin walled box girder bridge was established. According to the environment temperature distribution measured on site, the finite element model for two-dimension transient temperature field of the TuoketuoZhunge＇er Yellow River Bridge was established by using the plane quadrilateral isoparametric element PLANE55 and the surface effect element SURF151, the sunshine temperature distribution in the box girder at different time was calculated, and the calculated results were compared with the field test results. The results indicate that the maximum differential temperature between top flange and bottom flange on top slab of the box girder approximately occurs at 14：00 under sunshine; the curve of temperature-time measured on site matches well with theoretical calculation;the exponential curve can be fitted to the differential temperature in concrete wall slabs.