王斌, 郑山锁, 汪锋, 王帆. 考虑冻融损伤的钢筋混凝土框架节点恢复力模型研究[J]. 工程力学, 2017, 34(5): 105-115. DOI: 10.6052/j.issn.1000-4750.2015.11.0913
引用本文: 王斌, 郑山锁, 汪锋, 王帆. 考虑冻融损伤的钢筋混凝土框架节点恢复力模型研究[J]. 工程力学, 2017, 34(5): 105-115. DOI: 10.6052/j.issn.1000-4750.2015.11.0913
WANG Bin, ZHENG Shan-suo, WANG Feng, WANG Fan. RESTORING FORCE MODEL OF FREEZE-THAW DAMAGED RC FRAME JOINTS[J]. Engineering Mechanics, 2017, 34(5): 105-115. DOI: 10.6052/j.issn.1000-4750.2015.11.0913
Citation: WANG Bin, ZHENG Shan-suo, WANG Feng, WANG Fan. RESTORING FORCE MODEL OF FREEZE-THAW DAMAGED RC FRAME JOINTS[J]. Engineering Mechanics, 2017, 34(5): 105-115. DOI: 10.6052/j.issn.1000-4750.2015.11.0913

考虑冻融损伤的钢筋混凝土框架节点恢复力模型研究

RESTORING FORCE MODEL OF FREEZE-THAW DAMAGED RC FRAME JOINTS

  • 摘要: 为了研究冻融环境下钢筋混凝土框架节点的抗震性能,对6个经受不同冻融循环次数作用后的钢筋混凝土框架节点进行低周反复加载试验,分析框架节点的滞回曲线特性。基于试验结果,得到了简化三折线型骨架曲线模型,并给出了相应的确定方法。采用回归分析方法,得到考虑冻融损伤的钢筋混凝土框架节点的极限功比系数I数学表达式,进而确定基于循环耗能的循环退化指数,通过对构件在反复荷载作用下的屈服荷载、硬化刚度、卸载刚度以及承载力等各项力学性能的退化机理进行了描述,进一步建立适应于冻融损伤的钢筋混凝土框架节点的恢复力模型,并给出了具体的滞回曲线规则。研究表明:冻融作用使得节点梁纵筋粘结性能劣化明显,累积耗能随着冻融循环次数的增加而降低;通过考虑刚度、强度的循环退化规律能更好的反应冻融节点“捏缩”效应,更与实际吻合;建议的恢复力模型与试验结果想接近,可为该类结构的弹塑性时程分析提供理论参考。

     

    Abstract: To research the aseismic behavior of reinforced concrete (RC) frame joints damaged by freeze-thaw cycling, the hysteretic behavior of 6 RC frame joint specimens were investigated experimentally, which have been damaged by the freeze-thaw cycles under low cyclic reversed loading. Based on the test results, a trilinear skeleton curve model of frame joints was established, and the key parameters of the skeleton curve were determined. The limiting work ratio I of RC frame joints was expressed through regressive analysis, which considered freeze-thaw damage. The cyclic degradation indexes of RC frame joints based on freeze-thaw damage was proposed, so as obtained to describe the degradation law of specimens' mechanical properties such as yield load, hardening stiffness, unloading stiffness. And then, a restoring force model of RC frame joints based on freeze-thaw damage was established. The specific hysteretic rule was developed. The results show that the bond performance degradation of longitudinal reinforcements of a joint beam is obvious under the freeze - thaw, that the cumulative energy dissipated is decreased as the increase of cyclic numbers of freeze-thaw, and that the effect of pinching is affected by considering stiffness and strength reduction, which can well reflect the practical purpose. The study results will shed light on the theoretical research about the elastic-plastic dynamic analysis of RC structures.

     

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