青弋江某特大桥箱梁零号块水化热温度场分析

Study on the hydration heat and temperature field in zero block of Qing Yi River Bridge

通过有限元软件对青弋江某特大桥单箱三室预应力混凝土零号块箱梁进行水化热研究,根据现场记录的各测点的温度值与数值模拟结果对比分析,研究了预应力混凝土零号块箱梁在分层浇筑过程中温度变化和应力变化规律。结果表明:板越厚,温度越高,温度下降越缓慢;应力发生最大的部位位于横隔板与腹板的交界表面处、人洞表面处,对于分层浇筑,新旧混凝土处的横隔板与腹板的交界处是混凝土比较容易开裂的部位,横隔板与腹板交界表面处先受拉再受压,底板应力先受压后受拉。因此可以通过加强养护、布置温度钢筋等措施来改善混凝土内部的受力性能,为类似的工程提供参考。

The study of the hydration heat of the block zero of prestressed concrete box girder with a single box and triple cells of Qingyi River Bridge was done based on the finite element software.Base on temperature and numerical simulation results of field record- ing of each measuring point, the temperature change and stress variation of prestressed concrete box girder in a hierarchical block zero in the course of casting were analyzed. The results show that the thicker the board, the higher the temperature and more the temperature drops,the maximum stress occurs at the cross -junction of the surface of the separator and the web, also the surface of the people＇ hole. For the hierarchical placement, it is the old concrete crossbeam junction with the web that is easy to crack, crossbeam and web in- terface surface is under firstly tension and then bears pressure while the plate stress bears compression at first and then tension. There- fore,by strengthening the conservation, furnished temperature steel and other measures to improve the mechanical properties of con- crete. It can provide a reference for similar projects.