【作者】 马亚丽；

【导师】 张爱林；

【作者基本信息】 北京工业大学 ， 结构工程， 2006， 博士

【摘要】 目前,氯离子侵蚀环境下钢筋混凝土结构的耐久性问题是土木工程学术界和工程界备受关注的问题之一。由于氯离子的侵蚀、混凝土中钢筋锈蚀,结构的耐久性能逐渐衰退,危害了结构的承载能力,降低了结构的使用寿命。因此,在结构投入一定使用年限后,根据结构服役期间的状况和荷载、外界环境等信息,对损伤后混凝土构件的性能进行评定,确定结构的使用状态和耐久使用年限,是需要深入研究的重要课题。本论文在国内外对氯离子侵蚀环境下混凝土结构耐久性研究成果的基础上,综合运用概率理论、结构可靠性理论、混凝土结构理论、神经网络理论、结构动力学理论等基本理论和方法,结合实际检测数据,按照氯离子侵蚀、钢筋锈蚀、锈蚀构件性能、锈蚀构件寿命预测的思路对氯离子侵蚀环境下钢筋混凝土结构耐久寿命预测的有关问题进行了深入系统地研究,完成以下主要研究工作并取得相应成果:1、提出了氯离子侵蚀下基于规定可靠指标的混凝土结构耐久寿命的概率计算方法。建立了基于规定可靠指标的混凝土耐久寿命的随机预测模型,通过探讨影响因素的概率分布,分析了耐久可靠性的发展规律,运用工程实际检测数据对本文提出的耐久寿命方法进行了验证。通过建立腐蚀初始时间的概率模型,得出腐蚀初始时间的分布规律和概率密度函数。分析结果表明,利用该方法可以比较准确地计算氯离子侵蚀环境下混凝土结构的耐久寿命。本文的分析完善了氯离子侵蚀环境下混凝土结构耐久寿命的预测方法。2、建立了均匀腐蚀钢筋和局部腐蚀钢筋的可靠性分析方法。根据工程实际检测数据的统计分析,通过K-S检验得出了均匀腐蚀深度服从对数正态分布,局部腐蚀深度服从极值Ⅰ型分布的规律。探讨了腐蚀钢筋的可靠度计算方法,得出了腐蚀钢筋可靠性能随服役年限衰退的发展规律。分析了最大腐蚀深度与平均腐蚀深度比值的概率分布特征,通过K-S检验分析表明比值分布为正态分布或对数正态分布,这个指标建立了钢筋锈蚀整体平均状况与最严重状况的关系。本文研究得出的钢筋腐蚀程度统计规律,反映了腐蚀钢筋的概率特性,将为钢筋混凝土结构考虑钢筋锈蚀的耐久性评估及耐久可靠性研究提供理论依据。3、建立了基于坑蚀随机性的混凝土构件抗弯可靠性分析的简化模型,分析了基于坑蚀随机性的锈蚀钢筋面积参数和抗力统计参数的变化,得出了锈蚀钢筋面积参数、受弯构件抗力统计参数的变化趋势和可靠性能的发展规律。研究结果表明,坑蚀随机性对混凝土构件抗弯可靠性能的影响较为显著,所导致的可靠指标的降低明显,可靠指标随着独立同分布的随机变量的数目的增大而减小,并随着服役年限的增加下降较快。本文的分析完善了基于钢筋锈蚀的混凝土构件可靠更多还原

【Abstract】 At present, durability of concrete structures under chloride environment has become one of the problems widely concerned by the academic and engineer circles in civil engineering. Due to the ingress of chloride, reinforcements in concrete corrode, so the durability of structures declines gradually, which will destroy the carrying capacity and shorten the service life of structures. Therefore, after the structures have been used for years, it is a very important task to evaluate the performance of degraded structures in order to predict their residual service life according to the use condition, actual load information and external environment.Based on the current research achievements on durability under chloride environment, probability theory, structural reliability theory, concrete structures theory, neural network theory and structure dynamic theory are employed comprehensively in this dissertation. Some problems of durability of reinforced concrete structures under chloride environment were studied through the exploitation of experimental data, the rule of chloride ingress and steel bar corrosion, the performance of corroded member, and residual life prediction. The main issues and results in this dissertation are as follows:1、The probability method for the prediction of durable life based on the stipulated reliability index for concrete structures under chloride environment is presented in this dissertation. Then, probability prediction model of durable life is founded. Through discussing the probability characteristics of influencing factors, the law of durable reliability is analyzed, and the prediction method is validated by the experimental data. The probability model for the initial time of corrosion is founded; and the distribution type and the probability density function for the initial time of corrosion are obtained. The results show that the method proposed in this dissertation can calculate the durable life of reinforced concrete structures under chloride environment accurately. The work provided in this dissertation may perfect the prediction method for the durable life of concrete structures.2、The reliability analysis method of corroded steel evenly or locally was established. Based on the analysis of experimental data from actual engineering, corrosion distribution law of general corrosion was found to follow the lognormal distribution through K-S test, while the localized corrosion follows the extreme distribution of typeⅠ. Moreover, the calculation method of reliability for corroded reinforcements was discussed, and the law of reliability with the aging of corroded steel bars was obtained. The probability distribution of the ratio of the maximum corrosion depth to the general corrosion depth was analyzed. Through K-S test, it was found that this ratio follows the normal distribution or the lognormal distribution, which constructs a relationship between the mean corrosion condition and the worst corrosion condition. The research results about the statistic law of corroded steel bar更多还原