高强轻骨料混凝土框架中节点受剪性能研究

发布时间：2019-01-12 18:37

【摘要】：轻骨料混凝土具有强重比高、耐火性能好等特点,是一种发展前景良好的绿色建筑材料。使用高强轻骨料混凝土可以减轻建筑物自重,减小地震反应,但也存在脆性显著,在往复荷载作用下易发生脆性破坏。框架节点作为梁和柱传力枢纽,是框架结构的关键部件和抗震的薄弱环节。因此,研究高强轻骨料混凝土框架节点的抗震性能是必不可少的。本文基于试验研究,采用理论分析和数值模拟相结合的方法,对高强轻骨料混凝土框架中节点的受剪性能进行了研究,主要包括以下内容:(1)基于4个高强轻骨料混凝土框架节点往复加载试验,研究了高强轻骨料混凝土框架中节点的受剪性能。并基于我国规范(JGJ12-2006)、美国规范(ACI318-14、ACI352R-02)和欧洲规范(EC2),计算了中节点试件的抗剪强度。研究表明基于美国规范和欧洲规范的受剪承载力计算值与试验值较为接近,而基于我国规范的计算结果相对保守。(2)基于MCFT理论,建立高强轻骨料混凝土框架节点抗剪分析模型,并结合Attaalla抗剪模型和简化Attaalla抗剪模型,对本文和收集到的国内外共17组轻骨料混凝土框架节点试验试件进行受剪分析,与试验结果对比发现基于以上模型预测的节点试件抗剪强度值与试验值均吻合良好,MCFT模型可以较好地预测试件达到峰值应力前的受力行为,Attaalla模型考虑了混凝土的“受压软化”效应。(3)基于有限元分析软件Abaqus完成了该类节点的有限元模拟。模拟得到的节点破坏过程和核心区剪应力结果与试验结果相吻合,滞回曲线无明显捏缩现象。在此基础上,研究了节点核心区配箍率和轴压比对该类节点抗剪性能的影响规律,研究表明,这两大因素对高强轻骨料混凝土框架节点的影响规律与普通混凝土框架节点相类似。本文相关工作对了解轻骨料混凝土框架节点的破坏机理,保障地震区轻骨料混凝土框架的安全具有重要的理论意义和实用价值,促进了高强轻骨料混凝土这种绿色环保材料在框架结构中的推广应用。
[Abstract]:Lightweight aggregate concrete is a kind of green building material with good development prospect because of its high ratio of strong weight to weight and good fire resistance. The use of high strength lightweight aggregate concrete can reduce the weight of the building and reduce the seismic response, but there is also brittleness, which is prone to brittle failure under reciprocating load. The frame joint is the key component of the frame structure and the weak link of earthquake resistance as the load transfer hub of beam and column. Therefore, it is necessary to study the seismic behavior of high strength lightweight aggregate concrete frame joints. Based on experimental research, the shear behavior of joints in high strength lightweight aggregate concrete frame is studied by combining theoretical analysis and numerical simulation. The main contents are as follows: (1) based on the reciprocating loading tests of four high strength lightweight aggregate concrete frame joints, the shear behavior of the joints in the high strength lightweight aggregate concrete frame is studied. Based on JGJ12-2006, ACI318-14,ACI352R-02 and EC2, the shear strength of the specimens is calculated. The results show that the calculated value of shear capacity based on American Code and European Code is close to the test value, while the calculated results based on Chinese Code are relatively conservative. (2) based on MCFT theory, The shear analysis model of high strength lightweight aggregate concrete frame joints is established. Combined with Attaalla shear model and simplified Attaalla shear model, 17 groups of test specimens of lightweight aggregate concrete frame joints collected in this paper and at home and abroad are analyzed. Compared with the experimental results, it is found that the shear strength values of the joint specimens predicted by the above model are in good agreement with the test values, and the MCFT model can better predict the behavior of the specimens before the peak stress is reached. The Attaalla model takes into account the "compressive softening" effect of concrete. (3) the finite element simulation of this kind of joints is completed based on the finite element analysis software Abaqus. The simulated results of joint failure process and core shear stress are in agreement with the experimental results, and there is no obvious pinch phenomenon in hysteretic curves. On the basis of this, the influence of hoop ratio and axial compression ratio on the shear performance of the joints is studied, and the results show that, The influence of these two factors on high strength lightweight aggregate concrete frame joints is similar to that of ordinary concrete frame joints. The relevant work in this paper is of great theoretical significance and practical value in understanding the failure mechanism of lightweight aggregate concrete frame joints and ensuring the safety of light aggregate concrete frame in earthquake area. It promotes the application of high strength lightweight aggregate concrete, a green environmental protection material, in frame structure.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU375.4

【参考文献】