【作者】 张华；

【导师】 卫军；

【作者基本信息】 华中科技大学 ， 结构工程， 2011， 博士

【摘要】 钢筋锈蚀是影响混凝土结构耐久性的最重要因素。在现阶段混凝土结构耐久性研究之中,对锈蚀构件的承载能力的研究较多,而对变形,即刚度问题研究较少。本文在国家自然科学基金重点项目“氯盐侵蚀环境的混凝土结构耐久性设计与评估基础理论研究”(50538070)的资助下,对锈蚀弯压构件抗弯刚度退化规律开展研究,以期能够清晰的认识锈蚀弯压构件抗弯刚度的退化规律;在此基础上,建立锈蚀弯压构件抗弯刚度的计算模型,为耐久性劣化的混凝土结构进行安全性分析提供基础。本研究所进行的主要工作有:1.通过分析锈蚀弯压构件抗弯刚度的影响因素,明确钢筋锈蚀所引起的粘结力退化是影响锈蚀弯压构件抗弯刚度的关键因素。在此基础上,采用刚度解析法对锈蚀弯压构件的变形进行了理论分析,建立了未锈和锈蚀弯压构件抗弯刚度的计算模型;2.设计制作了15根不同锈蚀率不同偏心距的混凝土柱构件,通过通电快速锈蚀试验,建立了锈蚀构件锈蚀程度的估算公式;通过加载试验,得到试验构件的荷载-挠度曲线;在此工作基础上,对钢筋锈蚀程度对构件的变形性能进行了深入的研究。研究结果表明:当钢筋锈蚀率小于6%时,钢筋锈蚀对弯压构件的刚度影响不大,而当锈蚀率大于6%,钢筋锈蚀对弯压构件的刚度影响显著;3.在试验研究的基础上,对研究所建立的锈蚀弯压构件抗弯刚度的计算模型进行了参数反演,获得了锈蚀构件刚度计算模型中的粘结退化综合影响系数;通过与他人试验结果的广泛验证,证实本研究所建立的锈蚀弯压构件抗弯刚度的计算模型能够较好的反映锈蚀弯压构件的变形性能;4.通过对粘结退化综合影响系数的变化分析表明:当锈蚀率在0.04～0.12间变化时,粘结退化综合影响系数大致在1.3～2.4间变化,结合保护层锈胀开裂对截面有效尺寸的影响系数l的变化,本文理论计算结果与文献[42~44]的实验结论基本相同。5.运用大型商用有限元程序ANSYS,建立考虑锈蚀引起粘结性能退化的锈蚀混凝土偏压构件有限元计算模型。将模型计算结果和试验结果进行对比,验证本文所建有限元模型的可靠性,在此基础上,通过改变锈蚀率、纵筋直径、箍筋间距相关参数对钢筋混凝土偏压构件抗弯刚度进行了敏感性计算分析。更多还原

【Abstract】 Corrosion of reinforcement steel bar is recognized as one of the most important factors affecting durability of R.C. construction. Currently, research has mostly focused on compressive member’s carrying capacity and little research is done on the stiffness of compressive member,especially of eccentric compressive column. A key project, "chlorine salt erosion environment of concrete durability design and evaluation basic theory research" (50538070) by the National Natural Science Foundation studied the pressure of corroded bending stiffness degradation bending members is expected to clear understanding of rust bent pressure component bending stiffness degradation rules. On this basis, establish rust bent pressure component bending stiffness calculation model for deteriorating, durability of concrete structure security analyses provide basis.The main works are as follows:1. Through the analysis of the corrosion bent pressure component bending stiffness of influencing factors, clear rebar corrosion caused by the rapping effect degeneration is bent pressure component rust bending stiffness of the key factors. On this basis, using analytic method to corrode the bending stiffness of pressure component deformation are analyzed in theory, and establishes the not rust and rust bent pressure component bending stiffness of calculation model.2. Design for 15 root different corrosion rate of different eccentricity concrete column components. Using the electrify rapid corrosion test, it established the corrosion component degree of rust estimation formulae. Through the loading experiment, we obtained the load test components - deflection curves. In this work, on the basis of component rebar corrosion degree of deformation performance was discussed in the paper. The results of the study indicate that when rebar corrosion rate less than 6%, reinforcement corrosion on bending stiffness of pressure component is affected very little, but when the corrosion rate more than 6%, reinforcement corrosion on bending stiffness of pressure component had significant effects.3. Based on the experimental study on institute established corrosion bent pressure component bending stiffness calculation model of the parameter inversion, we obtained the rust component stiffness computation model of the bonding degradation comprehensive influence coefficients. Through experimental results with the extensive verification of other studies, we confirmed the established hypothesis in this study corrosion that bent pressure component bending stiffness calculation model can better reflect the rust bent pressure components deformation property,4. Through the bonding degradation comprehensive effect coefficient variation analysis, when the corrosion rate is 0.04 to 0.12 and bonding degradation between changes in the comprehensive influence coefficients are roughly 1.3 to2.4, combined with the cover between changes in section rust bilge crack effectively size effect coefficient change, the results of this study in reference [28 t030] conclusions are basically the same.5. Using large commercial finite element program ANSYS, we consider corrosion caused by bonding performance degradation corrosion concrete bias component, a finite element model. Through the finite element calculation results and experimental results verified the contrast, this paper built finite element model of reliability. On this basis, through the change of corrosion rate, longitudinal reinforcement diameter, stirrup spacing related parameters on the bending stiffness of reinforced concrete bias component the sensitivity calculation and analysis.更多还原