钢筋混凝土剪力墙平面外抗震性能试验研究及力学机理分析

Experimental study and mechanism analysis of out-of-plane seismic performance of reinforced concrete shear walls

  • 摘要: 相对于面内抗震性能,钢筋混凝土剪力墙的面外抗震性能偏弱且通常被忽略,这导致对剪力墙面外损伤的机理研究较薄弱并缺少明确的防护措施,剪力墙结构整体抗震性能也偏于不安全,亟须重视。为对比钢筋混凝土剪力墙在承受面内、外不同方向荷载时抗震性能的异同并明确关键影响因素,对典型剪力墙试件进行面内、外方向的低周往复加载试验,并对两个方向的宏观试验现象、滞回曲线、骨架曲线、刚度退化曲线、耗能能力及延性进行比对和分析。对剪力墙截面进行面内、外两个方向的弯矩⁃曲率模拟分析,将多组本构模型得到的结果与试验结果进行对比。结合有限元变参分析,分析了轴压比、墙体厚度、高宽比及混凝土等级等参数对面内、外抗震性能的影响。通过耐震时程分析研究了结构体系位移变化规律及墙体面外损伤的可能性。研究结果表明:剪力墙面外抗震性能明显弱于其面内抗震性能,承载力仅为后者的1/20~1/15,其中墙体厚度、高宽比是影响面内、外抗震性能的主要参数。利用本文建议的本构模型及部分传统本构模型可较准确地实现截面的面外非线性分析。对剪力墙进行抗震设计时,尤其是针对单向少墙结构体系,既要保证其面内抗震性能又要兼顾其面外抗震性能,合理地控制剪力墙墙体厚度、高宽比等指标。利用弹塑性耗能差率进行墙体损伤评估,具有区分度明显和阈值合理等特点。

     

    Abstract: Compared with the in-plane seismic performance, the out-of-plane seismic performance of reinforced concrete shear walls is weak and usually neglected, which leads to an inadequate study of the out-of-plane damage mechanism of shear walls and a lack of clear protective measures, and the overall seismic performance of shear wall structure is also unsafe, which needs urgent attention. In order to compare the similarities and differences in seismic performance of reinforced concrete shear walls when subjected to in-plane and out-plane loads in different directions and to clarify the key influencing factors, low cyclic loading tests are conducted on typical shear wall specimens in-plane and out-plane directions, and the macroscopic test phenomena, hysteresis curves, skeleton curves, stiffness degradation curves, energy dissipation capacity and ductility in both directions are compared and analyzed. The moment-curvature simulations of shear wall sections in both in-plane and out-plane directions are analyzed, and the results obtained from multiple sets of constitutive models are compared with the experimental results. Combined with the finite element variable parameter analysis, the effects of parameters such as axial pressure ratio, wall thickness, height-to-width ratio and concrete grade on the seismic performance of in-plane and out-plane are analyzed. Based on the endurance time analysis, the time-history response of structural displacement with seismic magnitude is studied. The results show that the seismic performance of shear walls outside the face is significantly weaker than that inside the face, and the bearing capacity is only 1/20~1/15 times of the latter, among which the wall thickness and height-width ratio are the main parameters affecting the seismic performance inside and outside the face. The out-of-plane nonlinear analysis of the cross-section can be performed more accurately and quickly by using the principal structure model proposed in this paper and some traditional principal structures. In the seismic design of shear walls, especially for the single directional wall with less structure, both in-plane and out-of-plane seismic performance should be ensured, and the thickness and aspect ratio of shear walls should be reasonably controlled. Wall damage assessment by using elastic-plastic energy dissipation difference rate has the characteristics of obvious differentiation and reasonable threshold value.

     

/

返回文章
返回