中文摘要：

为了有效预测疲劳损伤累积程度与桥梁剩余寿命,提出了钢筋混凝土桥梁结构在运营荷载下疲劳失效全过程数值模拟的简化方法。首先,根据混凝土及钢筋疲劳刚度退化、疲劳强度退化与疲劳残余变形演变规律,建立了混凝土及钢筋经历任意次数疲劳加载后的剩余强度包络线方程,基于混凝土单轴本构模型和钢筋理想弹塑性模型,建立了混凝土及钢筋疲劳本构模型;然后,在此基础上对文献提出的疲劳全过程分析法进行了改进,提出了疲劳损伤累积失效全过程数值分析法;最后,基于ABAQUS软件平台和该文方法,对某钢筋混凝土简支梁算例进行疲劳全过程数值分析。结果表明：利用该文方法得到的模拟值与试验值的相对误差处于合理范围之内,验证了该文方法的可靠性和实用性。

英文摘要：

In order to predict cumulative damage and residual life of highway bridges under fatigue loads,a simplified numerical simulation method for the deterioration process of in-service reinforced concrete（RC） bridges is proposed.Firstly,based on the rules of degradation of stiffness,strength and residual deformation of concrete and steel during fatigue loading,the envelope equation of the residual strength of concrete and steel in any cycle of a fatigue loading is established.Secondly,according to the uniaxial constitutive model of concrete and the ideal elastic-plastic model of reinforced rebar,fatigue constitutive model of concrete and reinforced rebar are built.At last,on this basis of the improved analytical method of the whole process of a fatigue loading,the numerical simulation method of the failure process of RC bridges under a fatigue load is proposed.A RC beam given as an instance is simulated by using this method and the finite element software of ABAQUS.The results show that the relative errors of both the simulation and experiment are controlled within the scope of engineering errors,which verifies the reliability and availability of the numerical analytical method.