An extreme loading on a reinforced concrete frame leads to severe increase in cracks in concrete as well as large strains in reinforcing bars. This, in turn, results in reduction of steel–concrete bond as well as an increase in the subsidiary effects of slip. In the current study, to include the slip effects in the numerical analyses, an indirect approach based on the results of pull-out test modeling is proposed. The proposed approach suggests a steel strength-reduction factor of 0.6 so as to apply to the bars prone to slip. This value is obtained based on the results of micro-modeling of available experimental pull-out tests using ABAQUS. To account for the bond-slip effect between concrete and rebar, adjacent nodes of concrete and rebar were connected using nonlinear springs. To estimate the length of slip prone zone, a sensitivity analysis on the collapse behavior of two reinforced concrete sub-frames from a 10-story building was conducted. The experimental data for the sub-frames were available. Corroborated with the experimental data revealed that if the length of the slip prone zone is considered to be twice the depth of the beam, the presented indirect approach will be capable of predicting the load–deformation response with a good accuracy. The obtained results showed the significance of considering slip effect in the analyses of reinforced concrete frames as well.

中文翻译：

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钢筋混凝土框架钢筋滑移模拟的等效方法

钢筋混凝土框架上的极端载荷会导致混凝土裂缝的严重增加以及钢筋的大应变。这反过来又会导致钢-混凝土结合力的降低以及滑移的辅助效应的增加。在目前的研究中，为了在数值分析中包括滑动效应，提出了一种基于拉拔试验建模结果的间接方法。建议的方法建议钢强度折减系数为 0.6，以便适用于容易滑动的钢筋。该值是基于使用 ABAQUS 对可用实验拉拔测试的微观建模结果获得的。为了解决混凝土和钢筋之间的粘结滑移效应，混凝土和钢筋的相邻节点使用非线性弹簧连接。估计滑移区的长度，对一栋 10 层建筑的两个钢筋混凝土副框架的倒塌行为进行了敏感性分析。子帧的实验数据是可用的。实验数据证实，如果将易滑区的长度视为梁深度的两倍，则所提出的间接方法将能够以良好的精度预测载荷-变形响应。所得结果也表明在钢筋混凝土框架分析中考虑滑移效应的重要性。所提出的间接方法将能够以良好的精度预测载荷-变形响应。所得结果也表明在钢筋混凝土框架分析中考虑滑移效应的重要性。所提出的间接方法将能够以良好的精度预测载荷-变形响应。所得结果也表明在钢筋混凝土框架分析中考虑滑移效应的重要性。