混凝土箱梁桥零号块水化热过程分析研究

结合黄沙港大桥工程实际,以箱室内外温度测试数据作为边界条件,根据混凝土水化过程的热传导方程,应用有限元分析程序ANSYS,对浇筑期间预应力混凝土连续箱梁零号块结构的温度场进行了仿真分析,并将仿真计算结果与混凝土连续箱梁的实测结果进行了比较。然后,应用ANSYS软件,采用增量法,动态模拟浇筑过程中水化热温度场变化引起的结构应力变化,得到了施工过程中应力场的时间和空间分布规律。分析表明,由于顶板和底板厚度较薄、内外温差较大,温度引起的残余应力也相对较大,而腹板最终的残余应力较小。因此,应该通过覆盖保温材料,控制厚度较薄的底板和顶板的内外温差,以改善内部混凝土后期受力状况,同时要注意控制预应力张拉时间和张拉力的大小。

Analysis of Hydration Heat for Block Number Zero of Reinforced Concrete Beam Bridge

This article makes a simulation analysis of the depositing period of block number zero in Huangshagang Bridge, a prestressed concrete continuous beam bridge, with the boundary conditions of actual temperature inside and outside the box beam by using finite element analysis software ANSYS,and makes a comparison of the results of FEA with the measurements. By using ANSYS, the temporal and spatial distribution laws of stress field in the construction process are formulated. It is proved that the residual stress caused by temperature is relatively high because of the thickness of the roof and the bottom slab and the temperature difference. It is advised that the coverage of thermal insulation materials and the control of the temperature difference of thin bottom slab and roof are helpful to improve the post stress state of concrete, and attention should be paid to the time and the force magnitude of pre-stressed tension.