持续荷载与氯离子侵蚀复合作用下RC梁抗弯性能试验研究

发布时间：2018-05-16 14:35

  本文选题：钢筋混凝土 + 氯离子　； 参考：《长沙理工大学》2014年硕士论文

【摘要】：混凝土结构耐久性是工程领域广泛关注的热点问题,氯离子侵蚀下的钢筋锈蚀是影响混凝土结构耐久性的重要因素之一,也是目前混凝土结构耐久性研究的关键内容。同时车辆超载现象在我国桥梁运营中普遍存在,车辆超载对钢筋混凝土桥梁服役期结构性能的影响不可忽视。因此研究荷载与氯离子复合作用对RC梁力学性能的研究显得尤为重要。本文采取试验研究与理论分析相结合的方法,系统研究了持续荷载对钢筋混凝土梁(RC梁)钢筋锈蚀率的影响,在此基础上,建立了考虑持续荷载影响下的锈蚀钢筋混凝土抗弯刚度及承载力计算方法,论文研究内容如下：1)进行无氯离子侵蚀作用梁的抗弯极限承载力试验,并基于规范对挠度的规定确定了钢筋混凝土梁超载状态与正常使用状态之间的界限。在此基础上,采用电化学的方法实现了受拉钢筋的加速锈蚀,并进行了正常使用荷载状态及两级超载作用下钢筋混凝土梁受氯离子侵蚀后的抗弯试验。结果表明,超载对于钢筋的锈蚀,挠度的增长有放大作用,对于承载力的减小有着明显的影响。2)分析了不同状态下构件荷载—跨中挠度关系,分析了影响锈蚀梁抗弯刚度的因素,建立了持续荷载作用下钢筋与混凝土间的应变协调关系,并对钢筋锈蚀率进行数据拟合,寻找出持续荷载等级与钢筋锈蚀率间的定量关系,并在此基础上建立了锈蚀后RC梁抗弯刚度的计算公式。3)对钢筋的锈蚀深度进行数据采集,通过对试验数据进行拟合,找出荷载与钢筋截面损失率之间的关系,对锈蚀梁进行抗弯承载力分析,并与试验数据进行对比,对该计算模型进行验证。结果表明本文所建立的公式计算精度较好,可为钢筋混凝土耐久性设计提供参考。
[Abstract]:Durability of concrete structures is a hot issue in the engineering field. Corrosion of steel bars under chloride ion erosion is one of the important factors affecting the durability of concrete structures, and it is also the key content of the research on durability of concrete structures at present. At the same time, the phenomenon of vehicle overloading is common in the operation of bridges in China. The influence of vehicle overload on the structural performance of reinforced concrete bridges during the service period can not be ignored. Therefore, it is very important to study the mechanical properties of RC beams. In this paper, the effect of continuous load on the corrosion rate of reinforced concrete beams and RC beams is systematically studied by combining experimental research with theoretical analysis. The calculation method of flexural stiffness and bearing capacity of corroded reinforced concrete under the influence of continuous load is established. The research contents are as follows: 1) the ultimate flexural bearing capacity of beams without chloride ion erosion is tested. The boundary between overloading state and normal service state of reinforced concrete beam is determined based on the deflection regulation of the code. On this basis, the accelerated corrosion of tensile steel bars was realized by electrochemical method, and the bending tests of reinforced concrete beams subjected to chloride ion erosion under normal service load and two-stage overload were carried out. The results show that overloading can amplify the corrosion of steel bar and increase the deflection of steel bar, and has obvious influence on the reduction of bearing capacity. 2) the load-span deflection relationship of members under different states is analyzed. The factors influencing the flexural stiffness of corroded beams are analyzed. The strain coordination relationship between reinforcement and concrete under continuous load is established, and the data fitting is carried out to find out the quantitative relationship between the grade of sustained load and the corrosion rate of steel bars. On the basis of this, the calculation formula of flexural stiffness of corroded RC beam is established. The data of corrosion depth of steel bar are collected. By fitting the test data, the relationship between the load and the loss rate of steel bar section is found out. The flexural bearing capacity of the corroded beam is analyzed and compared with the experimental data to verify the calculation model. The results show that the formula established in this paper has good calculation accuracy and can be used as a reference for the durability design of reinforced concrete.
【学位授予单位】：长沙理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U446.1
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本文编号：1897243