HPFL加固震损框架节点抗震性能研究

发布时间：2018-01-16 21:39

本文关键词：HPFL加固震损框架节点抗震性能研究　出处：《湖南工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：高性能水泥复合砂浆钢筋网薄层(High Performance Ferrocement Laminate,简称HPFL)加固法以其加固效果显著、易施工、造价低廉、防火和耐高温、耐久和抗老化、与原构件混凝土相容性和协调性好、不明显增大构件截面、环保性能好等综合特征,目前已取得了较系统的研究成果,但用该方法加固框架节点的研究尚未起步。本文设计了5个缩尺比例为1:2的混凝土框架节点试验模型,在相同的轴压比下施加水平低周反复荷载,研究不同震损程度的框架节加固后的抗震性能。对于试验中的5个试件,其中试件J0为对比试件,不预损直接加载至破坏;试件JR1不预损且不卸轴力情况下直接用HPFL加固,然后进行水平加载试验;试件JR2、JR3、JR4先在相同轴压比下施加水平低周反复荷载进行不同程度的预损,同样在不卸轴力情况下采用HPFL并以选取的最佳加固方式进行加固。通过试验研究、数值模拟分析和节点受剪承载力公式推导分析框架节点的受力性能、承载力状况、延性性能、刚度退化和耗能能力,得到的主要研究结论为:1、通过对有震损框架节点加固后的拟静力试验研究,发现不同震损程度的加固节点的承载力、抗裂性、刚度、延性和耗能能力等都有了大幅度的恢复,甚至超越了原试件。根据承载力、延性、耗能能力及破坏形态等性能,本文对各试件从开始受力到最终破坏的全过程进行了仔细观测,深入分析了试验中各种现象产生的原因。2、通过比较不同震损程度试件的加固效果发现,试件的震损程度越大,其极限荷载和极限位移提高的程度越小,结构延性系数提高程度逐渐降低。加固后试件的滞回环更加的饱满,试件的耗能能力也有一定的提高。试件的预损程度越小刚度退化越快。试件屈服以后,各试件刚度退化都趋于平缓,刚度退化趋于一致。加固后的混凝土框架节点要比未加固的框架节点的承载力和塑性变形能力更加的稳定,承载力也比未加固框架节点的承载力退化的缓慢。3、通过ANSYS有限元分析软件对加固前后的框架节点试件模型进行模拟对比,发现模拟结果和试验结果符合程度较高,在一定程度上验证了试验结果和模拟结果的可靠性。4、通过试验研究和对试件的加固施工过程,提出了采用HPFL的加固方法,并且总结出了采用HPFL加固RC框架节点的施工工艺流程,可以为后续的工程技术人员提供一定的参考。5、在充分分析了节点核心区的抗剪机理后,推导出了HPFL加固框架节点的抗剪承载力公式,将公式计算结果和试验结果进行比较,验证了公式的合理性,通过公式和试件的受力状态分析了节点核心区承载力的影响因素,可方便后续人员作为参考。
[Abstract]:High Performance Ferrocement Laminate. HPFL) reinforcement method has remarkable effect, easy construction, low cost, fire and high temperature resistance, durability and aging resistance, good compatibility and coordination with the original member concrete, and does not obviously increase the section of the member. At present, more systematic research results have been obtained because of the good environmental performance and other comprehensive characteristics. However, the study of strengthening frame joints with this method has not yet started. In this paper, five concrete frame joints with a scale of 1: 2 are designed and applied under the same axial compression ratio. The seismic behavior of frame joints strengthened with different earthquake damage degree is studied. For the 5 specimens in the test, the specimen J0 is a contrast specimen, without predamage loading directly to the failure. The JR1 of the specimen is strengthened with HPFL without predamage and axial force, and then the horizontal loading test is carried out. The specimen JR2 + JR3 + JR4 was subjected to horizontal low cycle repeated load under the same axial compression ratio to carry out different degrees of predamage. At the same time, HPFL is adopted in the case of no unloading axial force and the optimum reinforcement method is chosen. Through experimental research, numerical simulation analysis and shear bearing capacity formula of joints, the mechanical behavior of frame joints is deduced and analyzed. Bearing capacity, ductility, stiffness degradation and energy dissipation capacity, the main conclusion is: 1, through the seismic damage of the frame joints after the quasi-static test. It is found that the bearing capacity, crack resistance, stiffness, ductility and energy dissipation capacity of the strengthened joints with different earthquake damage degree have been greatly restored, even beyond the original specimen. According to the bearing capacity, ductility. In this paper, the whole process from the beginning to the final failure of the specimen is observed carefully, and the causes of various phenomena in the test are analyzed. 2. By comparing the strengthening effect of the specimens with different earthquake damage degrees, it is found that the greater the earthquake damage degree of the specimen is, the smaller the increase of ultimate load and ultimate displacement is. The ductility coefficient of the structure decreases gradually. The hysteretic loop of the strengthened specimen is more full, and the energy dissipation capacity of the specimen is also improved. The smaller the predamage degree of the specimen is, the faster the stiffness degenerates. The stiffness degradation of each specimen tends to be gentle and the stiffness degradation tends to be consistent. The reinforced concrete frame joints are more stable than the unreinforced joints in carrying capacity and plastic deformation. The bearing capacity is also slower than that of the unreinforced frame joints. The model of the frame joints before and after reinforcement is simulated and compared by ANSYS finite element analysis software. It is found that the simulation results are in good agreement with the test results, and the reliability of the test results and simulation results is verified to a certain extent. The reinforcement method of HPFL is put forward, and the construction process of RC frame joint strengthened by HPFL is summarized, which can provide a certain reference for the subsequent engineers and technicians. After fully analyzing the shear mechanism of the core zone of the joints, the shear bearing capacity formula of HPFL reinforced frame joints is derived, and the calculation results are compared with the experimental results, and the rationality of the formula is verified. The factors influencing the bearing capacity of the core zone of the joint are analyzed by the formula and the stress state of the specimen, which can be used as a reference for the follower.
【学位授予单位】：湖南工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU375.4;TU352.11

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