【作者】 徐善华；

【导师】 牛荻涛；

【作者基本信息】 西安建筑科技大学 ， 结构工程， 2003， 博士

【摘要】 论文采用理论分析、有限元模拟、试验研究及工程实测相结合的方法，围绕混凝土碳化、混凝土保护层锈胀开裂、构件承载力退化模型以及耐久性评估方法进行了系统的研究。 论文建立了以混凝土强度为主要参数，考虑其它因素修正的多系数混凝土碳化深度随机模型，并运用工程实测数据对所提出的模型进行了验证；围绕混凝土碳化残量进行了实际工程测试，首次提出了大气环境下混凝土碳化残量的随机模型，建立了混凝土中钢筋开始锈蚀的条件；提出了混凝土结构的碳化耐久性分析方法和碳化寿命预测方法，并结合一具体工程进行了碳化耐久性评估。 建立了混凝土保护层开裂前钢筋锈蚀量的实用预测模型；提出了混凝土保护层开裂的工程定义，建立了混凝土保护层锈胀开裂时锈蚀量的计算模型；通过混凝土保护层开裂前后理论模型比较及工程实测数据分析，给出混凝土保护层开裂后钢筋锈蚀量预测的实用模型；提出了混凝土结构锈胀开裂耐久性的评估方法和寿命预测方法。 建立了锈蚀钢筋混凝土构件锈蚀钢筋和混凝土之间局部滑移本构关系，研究了锈蚀钢筋混凝土构件有限元分析方法。首次考虑混凝土和钢筋之间的相对滑移，运用非线性弹簧单元刚度的变化模拟混凝土和钢筋之间粘结性能退化。较系统地分析了锈蚀钢筋混凝土受弯构件的刚度、钢筋和混凝土之间的相对滑移、钢筋应变和混凝土应变之间协调关系以及裂缝特征和破坏机理。研究了钢筋锈蚀程度和偏心距对锈蚀钢筋混凝土偏心受压构件受力性能的影响，建立了锈蚀钢筋混凝土偏心受压构件钢筋应变和混凝土应变之间的协调方程。 根据锈蚀钢筋混凝土构件钢筋和混凝土相对滑移较大、钢筋应变和混凝土应变不再符合平截面假定的特点，首次打破平截面假定的局限，运用极限平衡理论，建立了锈蚀钢筋混凝土受弯构件正截面承载力的计算模型和锈蚀钢筋混凝土偏心受压构件承载力的计算模型。所建立的模型更符合锈蚀构件的破坏机理，并与试验结果吻合较好。 利用快速电化学锈蚀方法，首次开展了锈蚀钢筋混凝土受弯构件抗剪性能试验，研究了箍筋锈蚀程度和剪跨比对锈蚀钢筋混凝土受弯构件抗剪性能的影响，以及斜截面承载力随剪跨比和钢筋锈蚀程度的变化规律。在试验基础上，进一步用极限平衡理论，首次提出了锈蚀钢筋混凝土受弯构件斜截面承载力的计算模型。 西安建筑科技大学博士学位论文 分析了现有钢筋混凝土结构的动态可靠度，提出了基于动态可靠度的承载力寿命分析方法。以锈蚀受弯构件为例，具体分析了正截面和斜截面承载力的统计参数、动态可靠指标随时间的变化，给出了正截面受弯和斜截面受剪控制的寿命和剩余寿命。更多还原

【Abstract】 Based on theoretical analysis, finite element simulation and experimental study, the concrete carbonation and concrete cover cracking for steel bar corrosion, deteriorating models of reinforced concrete member and the method of durability evaluation are studied in the paper.This paper presents a stochastic model for predicting the carbonated depth of concrete considering the uncertainties in concrete strength, the location of reinforcement, the environment and the condition of construction. The stochastic model is verified by a number of field data. Based on filed data, a stochastic model for predicting the induced corrosion depth of reinforcement also is presented. The condition of reinforcement initial corrosion has been established. Based on reliability theory, a method for calculating the carbonation durability period and carbonation reliability probability of reinforced concrete also is presented. The target reliability level which determines carbonation-life of concrete structure is also proposed in this paper. A predicting method for carbonation-life is given in this paper. An example of filed test is also given.Based on accelerated electrochemical corrosion experiment and field test, a simplified stochastic model for predicting the corrosion depth of steel bar before concrete cover cracking and a cracking criterion stochastic model for concrete cover are produced in this paper. These models consider the uncertainties in concrete strength, concrete cover depth, diameter of steel bar. Based on the comparison the corrosion depth before concrete cover cracking with that after cover cracking, a simplified stochastic model for predicting the corrosion depth of steel bar after cover cracking is given in this paper. This paper presents an approach for calculating the corrosion cracking durability period and reliability probability of concrete cover cracking. The target reliability level for cover cracking also is given in this paper.The local bond stress-slip relationship between corroded steel bars and concrete is advanced. It is studied that the nonlinear finite element model was simulated to analyze corroded reinforced concrete member. The influence of the corroded degree of steel bar on the stiffness, the slip between the steel bar and the concrete, the coordinate equation of steel strain with concrete strain, theappearance of crack and the failure mechanism are studied with nonlinear finite method. A coordinate equation of steel strain and concrete strain is derived for flexural member. Based on the fact that plane sections before bending don’t remain plane after bending, a calculation model for flexural strength of corroded reinforced concrete beam is proposed.The nonlinear finite element is simulated to analyze the eccentrically loaded column. The influence of the corrosive degree of steel bar and eccentricity on the loading performance of eccentrically loaded column is studied. A coordinate equation of steel strain with concrete strain is derived for eccentrically loaded corrosive reinforced concrete column. Based on Ihe fact that plane sections before bending don’t remain plane after bending, a calculation model for eccentrically loaded corrosive reinforced concrete column is proposed.Based on accelerated electrochemical corrosion, an experimental investigation on the shear behavior and ultimate shear strength, which included 18 corroded reinforced concrete beams and 3 un-corroded reinforced concrete beams, is presented in this paper. The effect of the corrosive degree of stirrups and the shear span to depth ratio on the shear performance of corroded flexure member is studied. A calculation model for shear strength of corroded flexural reinforced concrete beam is proposed.Since both the resistance and load are time-dependent quantities. They must be considered in the safety evaluation and service-life prediction of deteriorating reinforced concrete structures. The time-dependent reliability analyze are discussed as well.更多还原