钢筋混凝土结构腐蚀疲劳劣化过程的动态寿命评估

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发布时间：2021-09-13

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钢筋混凝土结构腐蚀疲劳劣化过程的动态寿命评估
李俊，吴瑾
(南京航空航天大学土木工程系，江苏南京210016)
摘要：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。
关键词：钢筋混凝土结构；腐蚀；疲劳；损伤；寿命；评估
中图分类号：TU375 文献标志码：A
Dynam ic Life Assessment of
of Coupled Corrosion
RC Structures in Process
and Fatigue Deteri0rati0n
LI Jun，WU Jin
(Department of Civil Engineering，Nanjing University of Aeronautics and Astronautics，Nanjing 210016，China)
Abstract：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 estab—
lished by the pre—corrosion m ethod 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
tim e，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 M iner linear cum ulative dam age theo—
ry． By way of example of a sim ply-supported T—beam ，the corrosion and fatigue life of the struc—
tures 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 w ill greatly
decrease．
Key words：reinforced concrete structure；corrosion；fatigue；damage；life；assessment
1 引言
腐蚀疲劳现象早在1917年就被提出，腐蚀疲劳
的研究大多集中在机械、船舶及航空领域 ]。由于
桥梁、海洋平台等结构在腐蚀环境下发生疲劳破坏
的情况比较复杂，目前国内、外对该课题的研究还较
少，已有的研究主要集中在钢筋混凝土结构的静力
性能(刚度、钢筋与混凝土的粘结性能、构件承载力)
和疲劳性能等方面 ]，研究方法主要是对未腐蚀
材料的s～N 曲线方程引入腐蚀参数进行修正以及
引入抗力随时间的下降系数(与腐蚀有关)考虑腐蚀
对疲劳寿命的影响，不足的是未考虑疲劳对腐蚀发
展的交叉影响。本文以Miner线性累积损伤理论
为基础，采用分级分层次的方法交叉、动态地考虑腐
蚀与疲劳对结构寿命的影响。