受火钢筋混凝土剪力墙加固后的抗震性能研究

发布时间：2019-06-27 15:09

【摘要】：近年来,随着高层建筑的日益增多,钢筋混凝土剪力墙结构以其良好的抗震性能被广泛使用,同时高层建筑火灾发生的频率也在增大,上海市胶州路教师公寓发生的大火就是惨痛的教训。火灾会严重削弱结构的承载性能,对结构造成很大的损伤,但一般通过修复加固还可以继续使用,故研究受火钢筋混凝土剪力墙的加固方法以及加固后的抗震性能具有重要的实际工程意义。本文进行了4片剪力墙的拟静力试验,包括未受火剪力墙、受火剪力墙、粘贴角钢加固的受火剪力墙、聚合物砂浆钢筋网加固的受火剪力墙,并从剪力墙的破坏形态、承载力、延性、耗能能力、刚度退化等方面进行了综合分析。试验结果表明：受火后剪力墙承载力和延性明显下降,呈现脆性破坏特征；粘贴角钢加固的剪力墙滞回环更加饱满,极限变形能力有很大提高,耗能能力也比常温试件增大,加固效果非常明显；聚合物砂浆钢筋网加固的剪力墙承载力和初始刚度都已恢复到常温水平,位移延性和耗能能力相对于受火试件均有较大提升,但仍较常温试件差。利用有限元软件ABAQUS6.10进行了混凝土剪力墙火灾下的温度场模拟,与试验结果对比证明所建立的有限元模型具有可靠性。结果表明混凝土沿厚度方向有明显温度梯度,在宽度和高度方向温度场均匀分布,计算得到的各点受火的最高温度是后续力学分析的基础。本文对ABAQUS 6.10进行二次开发,通过用户自定义材料UMAT子程序接口将有限元单元本构模型嵌入主程序中。在修正压力场理论的基础上,建立了钢筋混凝土平面应力单元,并对该单元进行改进,使之可以考虑火灾后钢筋和混凝土力学性能的退化,以及外贴钢材和砂浆钢筋网的加固作用。该方法能很好地预测峰值荷载前的力-位移关系、各部分的受力性能、变形能力,且整个计算过程时间很短。利用此程序,在现有《火灾后建筑结构鉴定标准》的基础上给出了可以根据剪力墙的参数和火灾荷载直观看出承载力的退化情况的简化鉴定方法,研究表明：对一定厚度的剪力墙,影响承载力退化系数的关键因素为受火时间和轴压比,可据此查表得出火灾后剪力墙承载力的退化系数。应用二次开发的平面应力单元,针对不同损伤程度的受火剪力墙,对粘贴角钢加固法和聚合物砂浆加固法分别进行了加固量化的参数分析,可以查表得出粘贴角钢加固的最小配钢率和聚合物砂浆加固法的最经济分布钢筋配筋率,能为工程应用提供一些参考。最后,在现有规范的基础上给出了粘贴角钢加固受火剪力墙的承载力计算公式和聚合物砂浆钢筋网加固受火剪力墙的承载力计算公式,可以对选定的加固量进行计算复核。
[Abstract]:In recent years, with the increasing of high-rise building, the structure of reinforced concrete shear wall is widely used in its good anti-seismic performance, and the frequency of fire in high-rise building is also increasing, and the fire in the teachers' apartment of Jiaozhou Road in Shanghai is a bitter lesson. The fire can seriously weaken the bearing performance of the structure and cause great damage to the structure. However, it can be continued to be used by the repair and reinforcement, so it is of great practical engineering significance to study the reinforcement method of the reinforced concrete shear wall and the anti-seismic performance of the reinforced concrete shear wall. In this paper, the quasi-static test of four shear walls is carried out, including the non-fire shear wall, the fire-receiving shear wall, the fire-receiving shear wall reinforced by the pasting angle steel, the heat-receiving shear wall reinforced by the reinforced mesh of the polymer mortar, and the damage form, the bearing capacity, the ductility and the energy-consuming capacity of the shear wall. The comprehensive analysis is made in the aspects of stiffness degradation and so on. The test results show that the bearing capacity and ductility of the shear wall after the fire are obviously reduced, and the brittle failure characteristic is presented; the shear wall hysteresis loop reinforced by the pasting angle steel is more full, the limit deformation capacity is greatly improved, and the energy consumption capacity is higher than that of the normal temperature test piece, and the reinforcing effect is very obvious; The bearing capacity and initial stiffness of the shear wall reinforced by the polymer mortar reinforced mesh have been restored to the normal temperature level, and the displacement ductility and energy dissipation capacity are greatly improved with respect to the fire-receiving test pieces, but are still lower than the normal-temperature test pieces. The temperature field of the concrete shear wall fire is simulated by using the finite element software ABAQUS.10, and the reliability of the established finite element model is shown in comparison with the experimental results. The results show that the concrete has obvious temperature gradient in the thickness direction, and the temperature field is uniformly distributed in the width and height direction, and the highest temperature of the received fire is the basis of the follow-up mechanical analysis. In this paper, the second development of ABAQUS 6.10 is carried out, and the constitutive model of the finite element unit is embedded in the main program through the user-defined material UMAT subprogram interface. On the basis of the theory of modified pressure field, the plane stress unit of reinforced concrete is set up, and the unit is improved, so that it can take into account the deterioration of the mechanical properties of the steel bar and concrete after fire, and the addition of steel and mortar steel mesh. The method can well predict the force-displacement relation before the peak load, the stress performance and the deformation capacity of each part, and the whole calculation process time is short. The simplified identification method of the degradation of the bearing capacity can be visually observed according to the parameters of the shear wall and the fire load on the basis of the existing 【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU352.11;TU352.11

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