混凝土梁式桥病害及承载能力研究

发布时间：2018-04-05 14:05

本文选题：钢筋混凝土简支梁　切入点：病害　出处：《东南大学》2015年硕士论文

【摘要】：桥梁作为公路交通咽喉,其安全畅通对整个路网乃至一个地区的经济和社会发展都有着至关重要的意义。混凝土梁式桥是公路上使用最常见的一类桥梁结构,也是修建时间较长、数量较多、分布地区很广的一种桥梁。在服役过程中,随着交通量的逐年增长,加上桥梁受环境因素影响以及本身的老化、破损等,桥梁结构的各类损伤、病害如何考虑,对其承载能力和正常使用状况(挠度)的影响如何分析,目前仍缺乏精确有效的评价方法。本文以公路桥梁典型病害及承载能力评价为出发点,应用有限元软件Midas以及经验理论推导公式,针对在役钢筋混凝土梁桥展开研究,论文主要研究内容如下：(1)本文首先对混凝土梁式桥的病害进行详细调研及系统分类,为实现病害调查工作的规范化、标准化奠定了基础,为承载能力的量化提供理论依据和基础。(2)基于混凝土碳化和钢筋锈蚀的退化模型,以碳化深度与时间之间的关系为纽带,通过Matlab编程求解,绘制了碳化深度与材料强度、钢筋截面面积之间的关系图,并计算得到不同碳化深度下的混凝土抗压强度和弹性模量、钢筋截面锈蚀率和屈服强度、以及混凝土和钢筋之间粘结能力的改变,为建立有损桥梁有限元分析模型奠定了基础。(3)应用Midas有限元软件,对材料强度和钢筋截面面积进行折减,模拟损伤,建立不同碳化深度下的有损桥梁有限元分析模型,并建立有损桥梁承载力计算方法。有限元模拟荷载试验,由不同损伤桥梁模型中提取挠度值,研究钢筋混凝土结构在荷载工况下的变形规律,最后拟合了以碳化深度为因变量的结构挠度和承载能力之间的关系表达式。(4)基于桥梁实测弯曲裂缝的统计参数,通过建立截面平衡方程,迭代计算,从而得到开裂区段刚度折减系数。设置裂缝宽度与裂缝位置,通过刚度折减建立有损钢筋混凝土简支梁桥的有限元模型,基于有限元模型进一步分析不同裂缝宽度、不同裂缝位置对于桥梁最大挠度值的影响。最后基于一座实桥的裂缝检测情况,分别按照本文方法与规范方法计算刚度折减系数,建立有限元分析模型进行对比,以期对规范提出一些有益的建议。
[Abstract]:As the throat of highway traffic, bridge is of great significance to the economic and social development of the whole road network and even a region.Concrete beam bridge is the most common type of bridge structure used in highway. It is also a kind of bridge with long construction time, large quantity and wide distribution area.In the service process, with the increase of traffic volume year by year, as well as the influence of environmental factors on the bridge and its own aging, damage, and so on, the damage of bridge structure, how to consider the disease,At present, there is still a lack of accurate and effective evaluation method to analyze the influence of its bearing capacity and normal service condition (deflection).Based on the evaluation of typical disease and bearing capacity of highway bridge, this paper applies the finite element software Midas and empirical theory to deduce the formula, and carries out the research on the in-service reinforced concrete beam bridge.The main contents of this paper are as follows: (1) in this paper, the diseases of concrete beam bridges are investigated in detail and systematically classified, which lays a foundation for the standardization and standardization of disease investigation.Based on the degradation model of concrete carbonization and steel corrosion, the relationship between carbonation depth and time is taken as the link, and the carbonation depth and material strength are plotted by Matlab programming.The relation diagram of the section area of steel bar is given, and the compressive strength and elastic modulus of concrete under different carbonization depth, the corrosion rate and yield strength of steel bar section, and the change of bond ability between concrete and steel bar are calculated.In order to establish the finite element analysis model of lossy bridge, the finite element analysis model of lossy bridge is established. The finite element analysis model of lossy bridge under different carbonization depth is established by using Midas finite element software to reduce the material strength and the section area of steel bar, and to simulate the damage.A method for calculating the bearing capacity of damaged bridges is established.In the finite element simulation load test, the deflection values are extracted from different damaged bridge models to study the deformation law of reinforced concrete structures under load conditions.Finally, the relation expression between deflection and bearing capacity of structure with carbonation depth as dependent variable is fitted. Based on the statistical parameters of measured bending cracks of bridge, the equilibrium equation of section is established and calculated iteratively.The stiffness reduction coefficient of cracking section is obtained.By setting crack width and crack position, the finite element model of damaged reinforced concrete simply supported beam bridge is established by stiffness reduction. Based on the finite element model, the influence of different crack width and crack position on the maximum deflection of the bridge is further analyzed.Finally, based on the crack detection of a real bridge, the stiffness reduction coefficient is calculated according to the present method and the code method, and the finite element analysis model is established and compared, in order to put forward some useful suggestions to the code.
【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U445.71

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