钢筋混凝土结构腐蚀疲劳劣化过程的动态寿命评估

Dynamic Life Assessment of RC Structures in Process of Coupled Corrosion and Fatigue Deterioration

为评估腐蚀条件下钢筋混凝土结构的疲劳寿命,采用预腐蚀的方法分级建立不同腐蚀率下钢筋混凝土结构的S～N曲线方程,然后在S～N曲线方程中再次考虑腐蚀率和应力水平的影响,建立lgN～lgS的一般线性关系,同时根据腐蚀率随时间的变化规律,按年限逐步计算结构在腐蚀及循环荷载作用下的时变疲劳累积损伤,最终根据Miner线性累积损伤理论动态预测结构的疲劳寿命。以某简支T梁为例进行腐蚀疲劳寿命评估,评估结果表明,钢筋混凝土结构在荷载及腐蚀环境共同作用下的性能和疲劳寿命会大大降低。

To assess the fatigue life of reinforced concrete （RC） structures under corrosion conditions, the S^N curve equations for the structures with different corrosion rates were established by the pre-corrosion method in a classifying way. In the equations, the influences of the corrosion rates and stress levels were then reconsidered, the general linear relationship of the lgN ～lgS was established and in accordance with the law of changing of the corrosion rates with time, the time-variant cumulative fatigue damage of the structures under the coupled corrosion and cyclic load was progressively calculated in terms of years and finally the fatigue life of the structures was dynamically predicted in accordance with the Miner linear cumulative damage theory. By way of example of a simply-supported T-beam, the corrosion and fatigue life of the structures was assessed and the results of the assessment demonstrate that the performance and fatigue life of the structures under the coupling action of the load and corrosion environment will greatly decrease.