锈蚀钢筋混凝土受弯构件裂缝宽度计算与分析研究

发布时间：2019-03-31 17:26

【摘要】：裂缝是钢筋混凝土结构承载力降低、耐久性失效的主要原因之一。鉴于此,国内外工程界对钢筋混凝土结构的裂缝问题都非常关注,并提出了一系列控制裂缝的方法和手段,其中比较普遍的是进行裂缝宽度的验算。与此同时,很多工程实例显示,钢筋锈蚀对在役工程结构的裂缝宽度发展具有某种程度的影响,但是在国内外各相关规范中却未有将钢筋锈蚀因素直接引入裂缝宽度计算公式的先例。为了探究钢筋锈蚀是否会对实际工程结构裂缝产生某种不可忽视的影响以及不同规范裂缝宽度计算公式对锈蚀钢筋混凝土结构裂缝的适用性问题,本文通过理论总结、规范对比和试验数据分析等途径开展了下列主要工作:介绍了目前国际上提出的钢筋混凝土结构荷载裂缝宽度计算理论与方法,阐述了钢筋与混凝土的粘结机理,包括光圆钢筋与螺纹钢筋粘结机理的差异,以及钢筋锈蚀对其粘结性能退化的影响;分析描述了未锈蚀钢筋混凝土受弯构件和锈蚀钢筋混凝土受弯构件在外荷载作用下的裂缝形态发展过程及其特征。整理了不同规范下的钢筋混凝土受弯构件裂缝宽度计算公式,并从包括裂缝控制方法、理论基础、荷载取值、钢筋应力、有效配筋率和保护层厚度等多个不同角度对各规范公式的差异和联系性作了分析比较。结合已有试验数据,计算了基于不同规范裂缝宽度计算公式下的试验梁裂缝间距和裂缝宽度理论值,借助有关软件对理论值与实测值的比值与锈蚀程度的关系进行了曲线拟合回归分析,根据拟合结果对比了不同规范下的裂缝宽度计算模式对试验梁裂缝的适用性,并引入了锈蚀影响因子,来对规范中钢筋混凝土梁裂缝计算公式进行修正,提出了基于适用规范的锈蚀钢筋混凝土受弯构件裂缝宽度修正系数表达式。
[Abstract]:Crack is one of the main reasons for the decrease of bearing capacity and durability failure of reinforced concrete structures. In view of this, the engineering circles both at home and abroad pay close attention to the crack problem of reinforced concrete structure, and put forward a series of methods and means to control the crack, in which the checking calculation of crack width is more common. At the same time, many engineering examples show that the corrosion of steel bars has a certain effect on the development of crack width of active engineering structures. However, there is no precedent that the corrosion factor of steel bar is directly introduced into the calculation formula of crack width in the relevant codes at home and abroad. In order to explore whether the corrosion of steel bar will have a certain influence on the cracks of the actual engineering structure and the applicability of the formulas for calculating the crack width of different codes to the cracks of the corroded reinforced concrete structure, this paper summarizes the theory in this paper. The main work is as follows: the theory and method of load crack width calculation of reinforced concrete structure are introduced, and the bond mechanism between reinforced concrete and reinforced concrete is expounded. It includes the difference of bonding mechanism between round bar and screw bar, and the influence of steel bar corrosion on the degradation of bond performance. The development process and characteristics of cracks in uncorroded reinforced concrete flexural members and corroded reinforced concrete flexural members under external load are analyzed and described. In this paper, the calculation formulas of crack width of reinforced concrete flexural members under different codes are sorted out, and the crack control method, theoretical basis, load value, steel stress, and so on, are included in this paper. The difference and connection of each criterion formula are analyzed and compared from different angles such as effective reinforcement ratio and cover thickness. Based on the existing experimental data, the theoretical values of crack spacing and crack width of the test beam based on the calculation formulas of crack width in different specifications are calculated. With the help of relevant software, the relationship between the ratio of theoretical value to measured value and corrosion degree is analyzed by curve fitting regression analysis. According to the fitting results, the applicability of crack width calculation mode under different codes to the crack of test beam is compared. The influence factor of corrosion is introduced to modify the formula of crack calculation of reinforced concrete beam in the code, and the expression of crack width correction factor of corroded reinforced concrete flexural member based on applicable code is put forward.
【学位授予单位】：长沙理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU375

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