Modern reinforced concrete buildings are often designed to dissipate energy during strong earthquakes by permitting the controlled formation of plastic hinges. Plastic hinges require assessment of residual capacity in post-earthquake situations. However, few past studies have investigated this topic, and results from experiments focused on undamaged structures are not always transferable to post-earthquake situations. Data from an experimental program, in which both cyclic and earthquake-type loadings were applied to nominally identical reinforced concrete beams, are used to investigate the relationship between residual crack widths and rotation demands. Assessment of the peak deformation demands incurred during a damaging earthquake is critical for post-earthquake assessments, but residual crack widths are shown to be dependent on several factors in addition to the peak rotation demand. Non-dimensional metrics capturing the distribution of cracking are proposed as a more informative alternative. The reduction in stiffness that occurs as a result of earthquake-induced plastic hinging damage was also investigated. A proposed model is shown to give a lower-bound estimate of the residual stiffness following arbitrary earthquake-type loadings.

中文翻译：

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中度损坏钢筋混凝土塑料铰链的震后评估

现代钢筋混凝土建筑通常被设计为通过允许塑性铰的受控形成来在强地震期间消散能量。塑性铰需要在震后情况下评估剩余容量。然而，过去很少有研究对此主题进行调查，并且针对未损坏结构的实验结果并不总是可以转移到震后情况。来自一个实验程序的数据，其中循环和地震类型的荷载被施加到名义上相同的钢筋混凝土梁，被用来研究残余裂缝宽度和旋转需求之间的关系。评估破坏性地震期间产生的峰值变形需求对于震后评估至关重要，但除了峰值旋转需求外，残余裂纹宽度还取决于几个因素。捕获裂纹分布的无量纲度量被提议作为一种提供更多信息的替代方法。还研究了由于地震引起的塑性铰链损坏而导致的刚度降低。所提出的模型显示了在任意地震类型载荷下给出残余刚度的下限估计。