混凝土连续刚构箱梁桥的温度场分析

Thermal Field of Rigid Frame Box Girder

根据某在建混凝土连续刚构箱梁桥的实际尺寸,建立有限元平面模型,模拟广东地区夏季时分桥梁所受到的热辐射、热对流等各种热物理边界条件,计算得出混凝土箱梁桥的瞬态温度场分布。根据以上的计算结果,讨论分析了整个箱梁截面温度场以1 d为周期随时间的分布。分析可知,最高温度大于50℃,位于顶板上表面,整个箱梁截面最大温差可大于20℃;箱梁截面温度最不均匀的时刻出现在午后时分,截面温度在沿高度方向上服从指数函数分布等。这些定量分析对工程设计具有参考价值。

A finite element model based on an under construction box bridge was established to simulate thermal process of the concrete box bridge such as radiation,convection,and to compute transient thermal filed distribution of the box girder.The thermal filed distribution of the girder cross-section was analyzed in a cycle of 24 hours according to the numerical results.It shows that the highest temperature which is at the top of the cross-section could reach 50 ℃,while the maximum temperature difference in the cross-section is about 20 ℃.It also tells that the most nonuniform distribution happens at noon,and the vertical temperature distribution satisfies exponential distribution.These quantitative analysis are valuable for further engineering design.