通过引入疲劳损伤因子和徐变损伤因子，建立了含疲劳和徐变损伤混凝土梁保护层锈胀开裂后钢筋锈蚀深度的计算模型；并根据混凝土结构耐久性设计标准，建立了由锈胀裂缝宽度控制的耐久性极限状态方程；运用Monte-Carlo数值模拟方法计算了6根混凝土试验梁在裂缝宽度限值范围内的可靠度；并采用验算点法，计算了腐蚀电流密度、混凝土抗压强度、保护层厚度和钢筋直径等四项参数的灵敏度。研究结果表明：随着锈蚀时间的增加，可靠度将从0.9下降到0.1，并且在60%疲劳寿命次数的循环荷载作用后，持荷时间增加3个月对梁的可靠度影响较小；保护层厚度的增加和钢筋直径的减小均可以提高梁的可靠度、减缓结构可靠度在钢筋锈蚀前期的下降速度，并且9mm的钢筋直径可以作为损伤混凝土梁耐久性设计的参照值；腐蚀电流密度、保护层厚度和钢筋直径三项参数的灵敏度较大，因此这三项参数是耐久性极限状态可靠度的主要影响因素。

By introducing the fatigue damage factor and the creep damage factor, the calculation model of the corrosion depth of the steel bar after the corrosion cracking of the protective layer of the concrete beam with fatigue and creep damage was established. According to the durability design standard of concrete structure, the durability limit state equation controlled by the rust crack width was established. The Monte-Carlo numerical simulation method was used to calculate the reliability of six concrete test beams within the crack width limit. The sensitivity of the four parameters including corrosion current density, concrete compressive strength, protective layer thickness and steel bar diameter was calculated by using the checking point method. The research results show that the reliability will drop from 0.9 to 0.1 with the increase of the corrosion time and the increase of the holding time for 3 months has little effect on the reliability of the beam after the cyclic loading of 60% of the fatigue life times. The increase of the protective layer thickness and the decrease of the diameter of the steel bar can both improve the reliability of the beam and slow down the decline rate of the structural reliability in the early stage of the corrosion of the steel bar. The steel bar diameter of 9 mm can be used as a reference value for the durability design of damaged concrete beams. The sensitivity of the three parameters of corrosion current density, protective layer thickness and steel bar diameter is so relatively large that three parameters are the main influencing factors of durability limit state reliability.

国家自然科学基金(51820105012)