【作者】 仲伟秋；

【导师】 赵国藩；

【作者基本信息】 大连理工大学 ， 结构工程， 2003， 博士

【摘要】 对既有混凝土结构的耐久性评估是混凝土结构耐久性课题的重要组成部分。 本文结合国家自然科学基金、辽宁省科学技术基金课题及部分工程结构的检测和评估项目，对钢筋混凝土结构的耐久性评估课题进行了一些研究。主要包括以下几方面内容： 1、给出一种抗力随时间变化时结构可靠度分析的方法，并且与现行规范的方法和等效抗力方法进行了比较。 2、尝试运用结合费克扩散定律的泊松分布来描述氯离子侵蚀现象，对氯离子侵蚀环境下钢筋混凝土结构的耐久性进行评估。 3、考虑失效模式间的相关性对结构整体可靠度的影响，用系统可靠度方法分析多种腐蚀因素作用下钢筋混凝土结构的可靠度。 4、根据属性识别理论，建立了既有钢筋混凝土构件质量综合评判的变权模型，对既有钢筋混凝土构件进行耐久性评估。根据评价因子实际贡献大小来确定权重，克服了人为给出权重的主观性，采用置信度准则来综合评判，相同类别之间还可以计算综合得分进行再分类。评判过程自始至终以实测值为基准，没有或很少受主观因素的影响。 5、结合既有钢筋混凝土结构定期或者不定期检测的结果，采用前面给出的可靠度分析或者综合评判的方法给出代表结构整体安全状况的指标，尝试运用灰色系统理论来预测既有钢筋混凝土结构的剩余使用寿命。 6、用电化学方法使钢筋混凝土压弯试件中的钢筋快速产生锈蚀，进行试件的低周水平反复加载试验，对试件的承载力、刚度、延性、耗能能力等进行了分析。试验结果表明，钢筋锈蚀率(钢筋失重率)大于某一程度(本文试验给出的数值约为4％)时，钢筋锈蚀对钢筋混凝土构件水平反复荷载作用下的各种性能有较大影响。随着钢筋锈蚀程度的增加，试件的承载力、刚度、延性、耗能能力等降低较快，滞回曲线的不对称特征更为明显。给出了钢筋锈蚀的混凝土构件骨架曲线的一种计算方法。更多还原

【Abstract】 Durability evaluation for existing R.C. structures is an important part of studies on durability of R.C. structures.Supported by the Natural Science Foundation of China, Science and Technology Foundation of Liaoning Province and some testing and evaluation projects for engineering structures, some studies on durability evaluation methods for existing R.C. structures are carried out. The main content are as follows.1. One method for reliability analysis of structures with resistance change with time considered is presented and compared to the methods given by the current building code and the equal resistance method.2. Poisson’s distribution combined with Fick’s diffusion law is used to describe invasion of chloride ions. Durability evaluation method of concrete structures subjected to invasion of chloride ions is presented.3. The influence of correlation of failure modes on structural reliability is considered. And structural reliability of R.C. structures subjected to several corrosive factors is analyzed using system reliability method.4. Based on attribute identification theory, the comprehensive evaluation model of variable weight for quality of existing R.C. structures is established to evaluate the durability of the structures. The weights are determined by the actual attribution of the evaluation factors and the subjectivity of artificial weights is overcome. The confidence criteria are adopted for comprehensive evaluation and the reclassifications can be made by calculating comprehensive scores among the same category. The evaluation is always based on the measured values and not or seldom affected by human factors.5. Combined with periodical and non-periodical testing results of existing R.C. structures, gray system theory is applied to predict remaining service life of existing R.C. structures. And the damage index representing the safety state of existing R.C. structures can be achieved by comprehensive evaluation method or reliability analysis presented above.6. Based on Faraday’s law in electrochemistry, the control equations for accelerated electrochemical corrosion of rebar are derived. Accelerated corrosion tests for rebar in R.C. members are carried out. Then performance experiments of R.C. members under repeated loading are made. And the bearing capacity, rigidity, ductility and energy dissipation characteristics of specimens are analyzed. The results show that when corrosion rate (weight loss) of rebar is more than some extent (approximately 4% given by this experiment), corrosion of rebar has important influence on hysteretic characteristics of R.C. members. As corrosionAbstractrate of rebar increases, the bearing capacity, rigidity, ductility and energy dissipation capacity decreases rapidly and asymmetric characteristics of hysteretic curves are more obvious. A calculation method for skeleton curves of R.C. members with corroded rebar is presented.更多还原