锈蚀钢筋混凝土构件承载力研究

发布时间：2018-01-09 08:01

本文关键词：锈蚀钢筋混凝土构件承载力研究　出处：《辽宁工程技术大学》2013年硕士论文　论文类型：学位论文

【摘要】：钢筋锈蚀是引起混凝土结构性能退化的最主要因素之一，现阶段迫切需要研究锈蚀钢筋混凝土构件的力学性能及其剩余承载力。论文主要分三个步骤进行构件承载力研究：混凝土中的钢筋锈蚀机理及电化学加速锈蚀实验研究、无锈蚀有限元模型验证和锈蚀有限元模拟研究。首先剖析了混凝土中钢筋的锈蚀机理，混凝土中的钢筋锈蚀经历两个步骤：首先是混凝土中性化和氯离子侵蚀造成在钢筋表面钝化膜破坏，之后钢筋失去保护，重新呈活化态，钢筋发生电化学锈蚀。在锈蚀机理研究的基础上，对电化学加速锈蚀实验进行了研究，分析了各类锈蚀实验与实际结构的相关性，为设计电化学加速锈蚀实验方法提供理论基础。其次进行了无锈蚀有限元模型验证，制作了六根钢筋混凝土简支梁，构件尺寸更加贴合实际，并设计了一种新的箍筋弯折工具。在纵筋与箍筋的交接处采取了一种新的绝缘方式，应用于实验构件的制作。设计并制作了分配梁、反力梁和模板，通过无锈蚀简支梁的加载试验判断所建立的考虑滑移的无锈蚀有限元模型是合理的，为进行考虑滑移的锈蚀钢筋混凝土简支梁承载力数值分析做了充分准备。最后在考虑滑移的无锈蚀模型合理的基础上，进行考虑滑移的锈蚀钢筋混凝土简支梁承载力数值分析。混凝土单元采用SOLID65单元，钢筋单元采用LINK8单元，钢筋-混凝土界面的粘结滑移关系采用Combine39三维非线性弹簧单元模拟，并将锈蚀钢筋与混凝土界面的局部粘结应力与局部滑移关系的本构模型引入Combine39弹簧单元，通过设置不同的锈蚀率以分析构件的承载力变化及破坏失效情况，同时考虑钢筋锈蚀造成的钢筋截面减少和屈服强度降低这两种因素，，建立了锈蚀钢筋混凝土简支梁的有限元模型并进行了承载力的计算，结果表明：随着锈蚀率的增加，梁的刚度降低、钢筋与混凝土之间的相对滑移增大、裂缝向跨中靠近、承载力明显降低并由延性破坏向脆性破坏转变。
[Abstract]:The corrosion of reinforcement is one of the most important factors causing deterioration of structural performance of concrete, the mechanical properties of the present stage is an urgent need to study the corrosion of reinforced concrete members and its residual capacity. The thesis is divided into three steps: Study on bearing capacity experimental study on accelerating corrosion of steel in concrete corrosion and electrochemical corrosion mechanism, finite element model verification and the corrosion study of finite element simulation.
The first analysis of the corrosion mechanism of reinforced concrete, steel corrosion in concrete through two steps: the first is the concrete carbonation and chloride ion erosion damage on the surface of steel passivation film, after losing reinforced protection, was re activated, the electrochemical corrosion of steel. Based on the study of corrosion mechanism on the electrochemical accelerated the corrosion experiments were conducted to study the correlation analysis and the actual structure of various types of corrosion experiment, provide a theoretical basis for the design of electrochemical accelerated corrosion experiments.
Secondly, no corrosion finite element model verification, made six reinforced concrete beams, the component size is more realistic, and designed a new stirrup bending tool. In the junction of longitudinal bars and stirrups adopted a new insulation, applied to manufacture the components. Designed and fabricated distribution of beam, the reaction beam and the template, by loading test no corrosion beam established no corrosion finite element model considering the slip is reasonable, for the consideration of reinforced concrete beam sliding bearing capacity numerical analysis has made full preparations.
Finally, considering the non slip corrosion model on the basis of reasonable, considering the corrosion of reinforced concrete beam sliding bearing capacity analysis. Numerical concrete elements using SOLID65 unit, steel units of the LINK8 unit, bond slip relationship reinforced concrete interface by using Combine39 three-dimensional nonlinear spring element simulation, and the local bonding interface of corroded steel bars and concrete stress and local slip constitutive relation model is introduced into Combine39 spring element, by setting different corrosion rate in the bearing capacity and the failure of the component change analysis, considering the reinforcement steel corrosion caused by the decrease of yield strength and reduce these two kinds of factors, established the finite element model of corroded reinforced concrete beams and the the bearing capacity calculation, the results show that with the increase of the corrosion rate, just reduce the beam of steel and concrete The relative slip between them increases and the crack is closer to the middle of the span. The bearing capacity of the crack is obviously reduced and the ductile failure is changed from the ductile failure to the brittle failure.

【学位授予单位】：辽宁工程技术大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU375

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