混凝土剩余抗压疲劳强度衰减模型试验研究

Experimental study on the attenuation model of concrete residual fatigue strength

为了研究混凝土剩余抗压疲劳强度衰减的规律,对63个尺寸为150 mm×150 mm×300 mm、强度为C30的混凝土棱柱体试件进行了抗压疲劳剩余强度试验;利用相关系数优化法进行了混凝土抗压疲劳剩余强度和疲劳寿命概率模型的参数拟合,得到混凝土抗压疲劳剩余强度和疲劳寿命的概率模型;引入材料疲劳剩余强度衰减模型,结合概率统计及可靠度理论推导出混凝土受压疲劳的P-R-N曲线。利用推出的P-R-N曲线可以对不同应力水平条件下经过不同疲劳加载次数后混凝土的剩余抗压强度进行预测,并能给出相应的可靠度。

In order to study the law of concrete residual compressive fatigue strength attenuation,the compres- sive fatigue residual strength test of concrete prism specimens with 63 150 mm× 150 mm×300 mm and strength of C30 was carried out.The parameters of the probabilistic model for the residual strength and fatigue life of concrete under compression fatigue were fitted by the correlation coefficient optimization method.The probability model of re- sidual strength and fatigue life of concrete under compression fatigue was obtained.Then the fatigue residual strength attenuation model was introduced, the P-R-N curves of compressive fatigue of concrete were obtained by using probability statistics and reliability theory, which can be used to predict the residual compressive strength of concrete under different stress levels,and can show the appropriate reliability.