高强钢筋约束高强混凝土柱结构性能试验研究

发布时间：2018-12-21 14:08

【摘要】：采用高强度材料是开展节能减排工作、走可持续发展道路的重要途径,高强钢筋和高强混凝土的应用能够节省材料的使用,节约资源,具有显著地经济效益。采用高强钢筋约束高强混凝土一方面能够提高约束混凝土的峰值应力,提高试件的承载能力,另一方面能够提高延性性能,防止试件突然破坏。目前,对高强钢筋约束高强混凝土柱结构性能的研究还不够充分。本文通过试验,研究了高强钢筋约束高强混凝土柱的结构性能。主要工作与成果如下:对13个配制高强钢筋(纵筋采用HTB650,箍筋采用HTH800H)的高强混凝土(C60)柱进行了轴心受压试验。分析了箍筋直径、箍筋间距、箍筋强度和体积配箍率等参数对高强钢筋约束高强混凝土柱在轴心受压时结构性能的影响,研究了各参数对试件破坏形态、荷载-变形曲线、延性性能、纵筋峰值应变、约束混凝土峰值应力和峰值应变的影响。提出了高强钢筋约束高强混凝土柱轴压受压承载力计算公式,建议纵筋强度设计值取540MPa,箍筋强度设计值取660MPa。轴心受压试验结果表明:与普通强度钢筋约束高强混凝土试件相比,高强钢筋约束高强混凝土对试件承载力和延性的改善作用更强,钢筋强度的提高能够提高约束混凝土的峰值应力和峰值应变,且采用高强钢筋的试件应力-应变曲线下降更加缓慢;高强钢筋对约束混凝土峰值应力、峰值应变的提高程度和试件延性性能的改善与钢筋对混凝土的约束作用强弱有关,约束作用越强,对峰值应力、峰值应变的提高和试件延性性能改善的效果越好;体积配箍率越大,钢筋的约束作用越强,当体积配箍率相同时,小直径、小间距配筋的约束作用大于大直径、大间距配筋;在一定的高强钢筋约束作用下,纵筋在峰值荷载时可以达到其屈服应变。对4个配制高强钢筋(纵筋采用HTB650,箍筋采用HTH800H)的高强混凝土(C60)短柱进行了低周反复加载试验。分析了剪跨比、纵筋强度、箍筋强度、箍筋直径和体积配箍率等参数对高强钢筋约束高强混凝土柱破坏形态、滞回特性、延性、极限位移角、耗能能力、箍筋应变和纵筋应变的影响。低周反复加载试验结果表明:与配有普通强度纵筋和普通强度箍筋的高强混凝土短柱相比,配有高强纵筋和高强箍筋的高强混凝土短柱具有较高的安全储备;高强箍筋在试件达到峰值荷载后发挥作用明显,能够显著改善试件的延性性能,提高试件抗倒塌能力;高强钢筋可以解决高强混凝土短柱的小剪跨比、高强混凝土材料脆性所导致的延性差的问题,即使在体积配箍率小于1.2%时也能够满足位移延性的要求;对于高强钢筋约束高强混凝土短柱,用极限位移角来反映试件的延性性能更加的合理,而且在计算配箍特征值时,需要对高强箍筋的屈服强度进行折减。
[Abstract]:The use of high strength materials is an important way to carry out energy saving and emission reduction and sustainable development. The application of high strength steel bar and high strength concrete can save the use of materials, save resources and have remarkable economic benefits. On the one hand, the peak stress of the confined concrete can be increased and the bearing capacity of the specimen can be increased by using high strength reinforced concrete. On the other hand, the ductility of the specimen can be improved and the sudden damage of the specimen can be prevented. At present, the research on the performance of high-strength reinforced concrete columns is not enough. In this paper, the structural properties of high-strength reinforced concrete columns confined by high-strength steel bars are studied. The main work and results are as follows: 13 high strength concrete (C60) columns with high strength reinforcement (HTB650, stirrups and HTH800H for longitudinal reinforcement) are tested under axial compression. The influence of the parameters such as the diameter of stirrups, the spacing of stirrups, the strength of stirrups and the ratio of volume stirrups on the structural performance of high-strength reinforced concrete columns under axial compression is analyzed. The failure patterns and load-deformation curves of the specimens under axial compression are studied. Effects of ductility, peak strain of longitudinal reinforcement, peak stress and peak strain of confined concrete. A formula for calculating the bearing capacity of high-strength reinforced concrete columns under axial compression is presented. It is suggested that the design values of longitudinal reinforcement strength and stirrups strength should be 540MPa and 660MPa respectively. The results of axial compression test show that high strength reinforced concrete can improve the bearing capacity and ductility of the specimens better than that of the specimens confined by ordinary strength steel bars. The increase of reinforcement strength can increase the peak stress and strain of confined concrete, and the stress-strain curve of high strength steel bar decreases more slowly. The improvement of peak stress of high strength steel bar to confined concrete, the improvement of peak strain and ductility of specimen is related to the restraint action of steel bar on concrete. The stronger the restraint action is, the stronger the peak stress is. The higher the peak strain and the better the ductility of the specimen are; When the volume ratio of hoop is the same, the constraint effect of small diameter and small spacing reinforcement is larger than that of large diameter, and the constraint effect of small spacing reinforcement is larger than that of large diameter. Under the constraint of a certain high strength steel bar, the longitudinal steel bar can reach its yield strain under the peak load. Four high strength concrete (C60) short columns prepared with high strength steel bar (HTB650, stirrups with HTH800H) were subjected to low cycle repeated loading test. The failure mode, hysteretic property, ductility, ultimate displacement angle, energy dissipation capacity of high-strength reinforced concrete columns confined by shear span ratio, longitudinal reinforcement strength, stirrups diameter and volume hoop ratio are analyzed. Effects of stirrups strain and longitudinal strain. The results of low cycle repeated loading test show that the high strength concrete short columns with high strength longitudinal reinforcement and common strength stirrups have a higher safety reserve than the high strength concrete short columns with high strength longitudinal reinforcement and high strength stirrups. The high strength stirrups play a significant role after the specimen reaches the peak load, which can significantly improve the ductility of the specimen and the ability of the specimen to resist collapse. The high strength steel bar can solve the problem of small shear span ratio of high strength concrete short column and the poor ductility caused by brittleness of high strength concrete material, even when the volume hoop ratio is less than 1.2, it can meet the requirement of displacement ductility. It is more reasonable to use the limit displacement angle to reflect the ductility of the specimen for the short columns with high strength reinforced concrete confined by high strength steel bar, and it is necessary to reduce the yield strength of the high strength stirrups when calculating the characteristic value of the stirrups.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU375.3

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