混凝土疲劳残余应变性能研究

Study of residual strain of concrete under fatigue loading

以单轴等幅抗压疲劳试验为基础 ,深入分析了疲劳变形的三阶段特性 ,研究了加载水平与疲劳变形第二阶段发展水平之间的关系 .通过对试验结果的拟合分析 ,得到了与试验相对应的、混凝土疲劳第二阶段起始点的残余应变随疲劳加载水平的增加先增后减的规律 ,并给出了与试验相对应的疲劳变形方程 .

Based on the experimental results of concrete under uniaxial compressive fatigue loading, the characteristics of three stages of fatigue strain development and accumulation are analyzed. It is found that the residual strain at the initial point of the second stage increases at first, then decreases with the increasing of the maximum fatigue load. But the residual strain at the end point of the second stage is not obviously related to the fatigue history and life, and is only related to the properties of the concrete material. According to the above analyses, a relationship between the residual strain, the cyclic number and the maximum fatigue stress in the three stages is proposed and it is further simplified as two stage model. This model agrees well with the experimental results.