氯离子侵蚀下受弯梁耐久性可靠度评估  

Reliability Evaluation of Beam Durability Under Chloride Erosion

作　　者：李扬[1] 杨侗伟 汪思维 LI Yang;YANG Dong-wei;WANG Si-wei(School of Civil Engineering and Architecture,Hubei University of Technology,Wuhan 430068,China;Zhongtian Construction Group Co.,Ltd.,Wuhan 430071,China)

机构地区：[1]湖北工业大学土木工程与建筑学院,武汉430068 [2]中天建设集团有限公司,武汉430071

出　　处：《硅酸盐通报》2018年第3期818-824,830,共8页Bulletin of the Chinese Ceramic Society

基　　金：国家自然科学基金(51508171);湖北省桥梁安全监控技术及装备工程技术研究中心开放基金(QLZX2014004)

摘　　要：以弯矩与抗弯承载力之比作为荷载水平指标,对氯离子在混凝土受弯梁中的扩散行为进行研究,建立荷载水平与氯离子扩散系数的函数关系,进而提出考虑荷载作用下钢筋表面氯离子浓度达到临界值的极限状态方程及相应耐久性可靠度计算方法。结合算例,对浪溅区混凝土梁构件在不同荷载水平下的耐久性可靠指标进行计算。结果表明:荷载水平对耐久性可靠指标β的影响较为显著,不考虑荷载作用时结构的耐久性可靠指标比考虑荷载作用时耐久性可靠指标偏高100%以上。从确保服役混凝土梁构件达到预期耐久性要求出发,建议对应浪溅区设计使用年限分别为30年、50年以及100年梁构件,相应的最小保护层厚度应分别取为60 mm,65 mm和75 mm,相应的最大水灰比限值均建议取为0.36。Based on the ratio of bending moment to flexural capacity as load level index,diffusion behavior of chloride ion in reinforced concrete under bending moment was studied.The function relationship between load level and chloride ion diffusion coefficient was established.Then the limit state equation and the calculation method of the corresponding durability reliability considering the concentration of chloride ions on the surface of rebar under load were proposed.The corrosion probability of reinforcement under different load levels in splash zone was calculated by this new method based on provided calculation examples.The calculation results show that the difference of durability reliability index could be more than 100%between considering the loading effect and not considering it,reflecting the significant effect of loading on reliability index^S.Based on the durability requirement of concrete beams,some revision suggestion is provided:It is recommended that for beams with the relevant design life of 30 years,50 years and 100 years in splash zone,the corresponding minimum protective layer thickness should be improved to 60 mm,65 mm and 75 mm respectively,and the corresponding maximum water-cement ratio limit should be controlled to be 0.36.

关 键 词：混凝土耐久性 可靠度指标 耦合作用 氯离子扩散 

分 类 号：TU528[建筑科学—建筑技术科学]