钢筋混凝土箱梁水化热测试及预应力张拉过程受力性能研究

Testing of Hydration Heat of Reinforced Concrete Box Girder and Mechanical Performance of Prestressed Tensioning Process

以高速铁路上典型的32m双线后张预应力混凝土箱梁为背景,通过水化热现场试验,分析混凝土内温度分布、温度升降及温度梯度情况,揭示早期水化热温度发展的一般规律,给出预防混凝土因水化热而产生裂缝的建议措施。结合ANSYS软件,从空间效应、弹性压缩及上拱度测试方面对箱梁预应力张拉过程中的受力性能进行研究。结果表明,根据经验水化热温度及温差控制值,混凝土不会由于峰值温度和最大温差产生的温度应力而出现裂缝,经实际观察所测试的箱梁表面无裂纹产生;另外,不考虑箱梁的空间受力效应即按初等梁理论计算低估了应力。

Based on the typical 32 m double-line post-tensioned prestressed concrete box girder on the high-speed railway, the hydration heat field test is used to analyze the temperature distribution,temperature rise and fall,and temperature gradient of the concrete,reveal the early development of hydration heat temperature. The general rule gives suggested measures to prevent concrete from cracking due to hydration heat. Combined with ANSYS software, the mechanical properties of box girder prestressed tension are studied from three aspects: Space effect,elastic compression and camber test. The results show that according to the empirical hydration heat temperature and temperature difference control value,the concrete will not crack due to the temperature stress generated by the peak temperature and the maximum temperature difference,and there is no crack on the surface of the box girder tested by actual observation. In addition,the stress is underestimated according to the elementary beam theory without considering the spatial stress effect of the box girder.