混凝土结构中考虑滑移效应的钢筋本构模型研究

RESEARCH ON THE CONSTITUTIVE MODEL OF STEEL BAR CONSIDERING SLIPPAGE EFFECT IN CONCRETE STRUCTURE

  • 摘要: 以钢筋混凝土(reinforced concrete,RC)结构中的钢筋滑移效应为研究对象,通过黏结应力分布简化模型,得到了钢筋应力-滑移关系,基于已有拉拔试验数据验证了该钢筋滑移关系的可靠性。结合塑性铰长度模型建立了可考虑滑移效应的钢筋应力-应变理论关系,分析了混凝土强度、钢筋直径和塑性铰长度等参数对该关系的影响,提出了考虑滑移效应的双线性钢筋本构模型。基于OpenSEES有限元平台,将该模型用于纤维截面的宏观单元模型中模拟RC柱的侧向荷载-位移反应,通过与已有试验结果、不考虑钢筋滑移效应的纤维模型计算结果及考虑钢筋滑移效应的零长度纤维模型计算结果进行对比分析,验证了本文模型的精度和可靠性,并对其适用范围进行了讨论。结果表明,基于本文钢筋本构的纤维模型可以更为准确地计算RC柱的荷载-位移曲线,且能够考虑由钢筋滑移变形引起的柱顶附加水平位移。

     

    Abstract: To study the rebar slippage effects in reinforced concrete (RC) structures, the steel stress-slip relationship is derived by simplifying the distribution of the bond stress. Based on the existing pull-out test results, the derived steel stress-slip relationship is verified. The model of the plastic hinge length is introduced, and the slippage effects considering steel stress-strain theoretical relationship is established. The influence of the concrete strength, diameter of steel bar, and plastic hinge length on this relationship is analyzed and a simplified constitutive model of steel bar considering slippage effect is proposed. Based on the finite element platform OpenSEES, the fiber beam-column model implemented by the proposed model proved to be accurate and reliable by comparison with the existing experimental results, the fiber model without considering rebar slippage deformation, and the zero-length fiber model. The application scope of the proposed model is further discussed. The results show that the lateral load-displacement response of the RC column can be exactly calculated by the fiber model based on the proposed model; while the column additional lateral displacement caused by rebar slippage deformation can be well predicted.

     

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