锈蚀钢筋混凝土梁的抗冲击性能研究

发布时间：2018-05-02 14:31

本文选题：钢筋锈蚀 + 混凝土梁　；参考：《湖南大学》2015年硕士论文

【摘要】：冲击荷载常对钢筋混凝土结构造成重大破坏,严重影响结构的安全并危及人们的生命及财产安全。在冲击荷载作用下,随着材料应变率效应和结构惯性效应的出现,结构的材料性能、力学特性以及破坏形式明显异于常规荷载作用下的结构性能,结构行为也更加复杂。钢筋锈蚀常使得钢筋混凝土结构的性能出现劣化,进而对混凝土结构的安全和适用性造成重大影响。钢筋锈蚀导致的结构承载能力降低、破坏模式改变、粘结性能退化一直是海洋环境、近海环境以及某些特殊的工业环境下结构安全的一大隐患。在混凝土结构抗冲击性能方面和耐久性退化问题方面,虽然对于两者单独的研究成果已不少见,但对于二者同时存在时结构或构件力学性能的研究却尚未发现。基于此,本文采用试验研究的方式对锈蚀钢筋混凝土梁的抗冲击性能进行研究,试图揭示钢筋混凝土梁破坏模式、抗冲击能力和挠度变形等随钢筋锈蚀程度发展的劣化过程。本文主要研究工作如下:(1)通过对已有的钢筋锈蚀后钢筋与混凝土之间的粘结性能试验的数据进行收集和统计分析,提出了计算锈蚀后钢筋与混凝土之间粘结强度的模型;(2)对钢筋的加速锈蚀过程进行了研究,介绍钢筋混凝土梁静电流加速锈蚀试验的原理、试验装置以及锈蚀量的控制。对腐蚀后的试验梁的锈胀破坏以及钢筋的锈蚀形态进行分析和讨论;(3)对4根不同锈蚀程度的钢筋混凝土梁进行静载试验,研究混凝土梁的承载能力和和挠度变形随钢筋锈蚀程度发展的劣化过程。得到了纵筋锈蚀程度、锈胀裂缝平均宽度和最大宽度三个因素对梁抗剪承载力的影响规律;(4)对8根不同锈蚀钢筋混凝土梁进行落锤冲击试验研究,重点考察纵筋锈蚀程度和落锤冲击速度对混凝土梁的冲击破坏形态、锤头冲击力时程、支座反力时程和能量耗散方面所产生的影响,揭示钢筋锈蚀程度对混凝土梁抗冲击行为劣化过程的影响机理,最终提出了抗冲击简化计算公式。
[Abstract]:Impact loads often cause great damage to reinforced concrete structures, seriously affect the safety of structures and endanger people's lives and property safety. Under impact load, with the emergence of strain rate effect and inertia effect, the material properties, mechanical properties and failure forms of the structure are obviously different from those of the conventional load, and the structural behavior is more complex. The corrosion of steel bars often leads to the deterioration of the performance of reinforced concrete structures, which has a great impact on the safety and applicability of concrete structures. The corrosion of steel bar leads to the decrease of the structural bearing capacity, the change of the failure mode and the degradation of the bond property. It is always a hidden danger for the structural safety in the marine environment, the offshore environment and some special industrial environments. In the aspects of impact resistance and durability degradation of concrete structures, although it is not uncommon for them to be studied separately, the research on the mechanical properties of structures or members when they exist at the same time has not been found yet. Based on this, this paper studies the impact resistance of corroded reinforced concrete beams by means of experimental research, and attempts to reveal the deterioration process of reinforced concrete beams such as failure mode, impact resistance and deflection deformation with the development of corrosion degree of steel bars. The main research work of this paper is as follows: (1) through the collection and statistical analysis of the existing data of bond behavior test between corroded steel bar and concrete, A model for calculating the bond strength between corroded steel bar and concrete is presented. The accelerated corrosion process of steel bar is studied. The principle of static current accelerated corrosion test of reinforced concrete beam, the experimental device and the control of corrosion quantity are introduced. This paper analyzes and discusses the corrosion damage of corroded test beams and the corrosion morphology of steel bars. The static load tests of four reinforced concrete beams with different corrosion degrees are carried out. The deterioration process of the bearing capacity and deflection of concrete beams with the corrosion degree of steel bar is studied. The effects of three factors on the shear bearing capacity of the beams, including the corrosion degree of longitudinal reinforcement, the average width of rust expansion crack and the maximum width, are obtained. (4) eight corroded reinforced concrete beams with different corrosion are tested by drop weight impact test. The effects of corrosion degree of longitudinal reinforcement and impact velocity of drop weight on the impact failure pattern of concrete beam, the impact time history of hammer head, the time history of bearing reaction force and energy dissipation are investigated. The influence mechanism of the corrosion degree of steel bar on the deterioration process of concrete beam's impact behavior is revealed. Finally, a simplified formula for calculating the impact resistance is put forward.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU375.1

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