Experimental study on probability model of concrete compressive fatigue life

Fatigue life test was carried out to 27 concrete prism specimen whose strength were C30,the parameter estimation method using small sample data for lognormal distribution and the three parameter Weibull distribution was deduced.Based on the test data,combined with the relative coefficient optimization method,probability models of concrete fatigue life were fitted by lognormal distribution and the three parameter Weibull distribution,the fatigue life models of C30 concrete were determined by fitting the distribution parameters,fatigue reliability of an example was calculated by those concrete fatigue life models.The fitting results show that the concrete fatigue life based on the two probability distribution models are both well fitted,but the three parameter Weibull distribution has higher fitting precision.Research on fatigue damage shows that the reliability level of repeated damage caused by concrete structural fatigue,in an inverse ratio to the loading period,roughly follows the downward tendency of the second-degree parabola,and the damage,in direct ratio,speeds up rapidly in accord with the cycle of loading time.