外包钢板加固钢筋混凝土桥墩锈蚀后的力学性能研究

发布时间：2018-09-09 17:35

【摘要】：高架桥作为交通网络中的重要组成部分,当地震来临时,高架桥能否正常使用决定了救灾物资能否第一时间内运进灾区以及地震伤员能否第一时间得到救治,所以它们的安全性显得异常重要。诸多地震灾害调查报告表明,桥梁在地震过程中发生严重破坏甚至倒塌主要是由于桥墩的破坏所致。由于钢筋混凝土桥墩在地震作用下容易在柱脚附近造成损伤,作为该类桥墩的加固方法,在钢筋混凝土桥墩周围包裹钢板的方法得到广泛采用。然而实际使用中发现,由于积水、腐蚀环境等的影响,钢板出现了不同程度的锈蚀现象,这些由锈蚀引起的损伤对于外包钢板加固钢筋混凝土桥墩产生多大影响,需要通过试验和数值模拟方法加以研究。本文以外包钢板加固钢筋混凝土桥墩为研究对象,采用二维和三维弹塑性有限元分析方法,研究不同锈蚀模式以及由锈蚀引起的钢板与混凝土间粘结性能退化对桥墩水平承载力与滞回性能的影响规律。开展的研究工作以及得出的主要结论如下:(1)建立二维弹塑性有限元分析模型研究桥墩底部附近钢板锈蚀率、锈蚀模式等参数对桥墩水平承载力的影响。研究发现桥墩的水平承载力随着底部钢板锈蚀率的增加而减小。对于腹板而言,局部锈蚀模式引起的水平承载力劣化远大于均匀锈蚀模式。(2)建立三维弹塑性有限元分析模型研究桥墩底部钢板锈蚀位置、钢板厚度方向锈蚀程度、宽度方向锈蚀范围、以及由锈蚀导致的钢板-混凝土界面粘结性能退化等参数对桥墩水平承载力的影响。研究发现,钢板底部附近高度方向小范围的局部锈蚀对桥墩水平承载力影响不大;当腹板底部宽度方向局部锈蚀时,桥墩水平承载力的退化程度与钢板锈蚀位置、厚度方向锈蚀深度以及锈蚀影响范围等密切相关,而翼缘底部宽度方向局部锈蚀时桥墩水平承载力的退化程度仅与厚度方向锈蚀深度以及锈蚀影响范围相关,与锈蚀位置无关;随着钢板与混凝土界面粘结性能的不断退化,两者协同工作能力不断下降,桥墩的水平承载力也逐渐降低。(3)建立以底部钢板锈蚀程度、钢板与混凝土界面粘结性能为变化参数的三维弹塑性有限元分析模型,从骨架曲线、延性系数、刚度退化系数、等效粘滞阻尼系数等四个方面研究上述变化参数对桥墩抗震性能的影响。计算结果表明,随着钢板底部锈蚀情况越严重,其抗震性能越差;钢板与混凝土间粘结性能越好,则其抗震性能越佳。以上研究成果有望为现役桥墩的维护管理与加固提供参考依据。
[Abstract]:Viaduct is an important part of traffic network. When the earthquake comes, the normal use of viaduct determines whether the relief materials can be transported into the disaster area in the first time, and whether the injured in the earthquake can be treated in the first time. So their safety is extremely important. Many seismic disaster investigation reports show that the serious damage and even collapse of bridges in the course of earthquake is mainly caused by the damage of bridge piers. As the reinforced concrete pier is easy to cause damage near the column foot under seismic action, as the reinforcement method of this kind of pier, the method of enclosing steel plate around the reinforced concrete pier is widely used. However, it is found in practical use that due to the influence of water and corrosion environment, the steel plate has different degree of corrosion phenomenon, and the damage caused by corrosion has a great impact on the reinforcement of reinforced concrete pier strengthened with steel plate. It needs to be studied by means of experiments and numerical simulation. In this paper, the reinforced concrete pier strengthened with steel plate is used as the research object, and the two-dimensional and three-dimensional elastic-plastic finite element analysis method is used. The effects of different corrosion modes and the degradation of bond behavior between steel plate and concrete on the horizontal bearing capacity and hysteretic behavior of pier are studied. The main conclusions are as follows: (1) A two-dimensional elastic-plastic finite element analysis model is established to study the influence of steel plate corrosion rate and corrosion model on the horizontal bearing capacity of the pier. It is found that the horizontal bearing capacity of the pier decreases with the increase of the corrosion rate of the bottom steel plate. For web, the horizontal bearing capacity deterioration caused by local corrosion mode is much larger than that caused by uniform corrosion mode. (2) Three-dimensional elastic-plastic finite element analysis model is established to study the corrosion location of steel plate at the bottom of pier and the corrosion degree of steel plate thickness. The influence of the corrosion range in width direction and the degradation of bond behavior between steel plate and concrete interface caused by corrosion on the horizontal bearing capacity of pier. It is found that the horizontal bearing capacity of the pier is not affected by the local corrosion in the direction of the height near the bottom of the steel plate, and the degradation degree of the horizontal bearing capacity of the pier and the corrosion position of the steel plate are obtained when the width direction of the web bottom is locally corroded. The thickness direction corrosion depth and corrosion influence range are closely related, while the horizontal bearing capacity degradation degree of bridge pier is only related to thickness direction corrosion depth and corrosion effect range, but not to corrosion location when the width direction of flange is partial corrosion. With the continuous degradation of the bond property between steel plate and concrete interface, the cooperative working ability of both decreases, and the horizontal bearing capacity of bridge pier decreases gradually. (3) the corrosion degree of steel plate at the bottom is established. Three-dimensional elastic-plastic finite element analysis model with the interface bond property of steel plate and concrete as variable parameter, from skeleton curve, ductility coefficient, stiffness degradation coefficient, The influence of the above parameters on the seismic performance of pier is studied from four aspects, such as equivalent viscous damping coefficient. The results show that the worse the corrosion at the bottom of the steel plate is, the worse the seismic behavior is, and the better the bond performance between the steel plate and concrete is, the better the seismic performance is. The above research results are expected to provide a reference for the maintenance, management and reinforcement of existing piers.
【学位授予单位】：上海交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U443.22;U441

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