In this study, a numerical model for tracing the behavior of eccentrically loaded slender reinforced concrete (RC) columns bent in single and double curvature, and subjected to elevated temperatures is presented. The developed model incorporates the high-temperature material properties, the nonlinear behavior of concrete sections, time dependent effects, and the nonlinear responses of slender RC columns. Based on Newton–Raphson method, an iterative technique, wherein strain and curvature are concurrently iterated, is used to find the strain distribution on the cross-section. By proposing a simple and reliable calculation procedure, the lateral deflection is calculated using numerical and searching techniques. The compatibility between forces and deformations at a joint in the column is established by another iterative technique, which involves the analysis of the whole column. The validity of the analytical model is established by comparing its predictions with results obtained from laboratory tests found in literature. A parametric study is conducted to investigate the effect of end eccentricity conditions on columns bent in single and double curvatures. It was found that lateral deflection plays an important role on column responses when subjected to fire. This finding confirms the usefulness of lateral deflection as a powerful tool in validating eccentrically loaded slender RC columns. It was also found that unwinding at elevated temperature has detrimental effect on columns bent in double curvature. It was observed that for all columns, there exists a critical eccentricity after which column responses to fire change.

中文翻译：

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高温下单曲率和双曲率弯曲的细长钢筋混凝土柱的行为

在这项研究中，提出了一个数值模型，用于追踪偏心加载的细长钢筋混凝土 (RC) 柱在单曲率和双曲率下弯曲并受到高温的影响。开发的模型结合了高温材料特性、混凝土截面的非线性行为、时间相关效应和细长 RC 柱的非线性响应。基于 Newton-Raphson 方法，一种迭代技术，其中应变和曲率同时迭代，用于找到截面上的应变分布。通过提出简单可靠的计算程序，使用数值和搜索技术计算横向挠度。柱中节点处的力和变形之间的兼容性是通过另一种迭代技术建立的，这涉及到整个列的分析。分析模型的有效性是通过将其预测与从文献中发现的实验室测试获得的结果进行比较来建立的。进行参数研究以研究端部偏心条件对单曲率和双曲率弯曲的柱的影响。研究发现，当受到火灾时，横向挠度对柱的响应起着重要作用。这一发现证实了横向偏转作为验证偏心加载细长 RC 柱的有力工具的有用性。还发现在升高的温度下展开对双曲率弯曲的柱具有不利影响。据观察，对于所有柱子，都存在临界偏心率，在此之后柱子对火的响应发生了变化。分析模型的有效性是通过将其预测与从文献中发现的实验室测试获得的结果进行比较来建立的。进行参数研究以研究端部偏心条件对单曲率和双曲率弯曲的柱的影响。研究发现，当受到火灾时，横向挠度对柱的响应起着重要作用。这一发现证实了横向偏转作为验证偏心加载细长 RC 柱的有力工具的有用性。还发现在升高的温度下展开对双曲率弯曲的柱具有不利影响。据观察，对于所有柱子，都存在临界偏心率，在此之后柱子对火的响应发生了变化。分析模型的有效性是通过将其预测与从文献中发现的实验室测试获得的结果进行比较来建立的。进行参数研究以研究端部偏心条件对单曲率和双曲率弯曲的柱的影响。研究发现，当受到火灾时，横向挠度对柱的响应起着重要作用。这一发现证实了横向偏转作为验证偏心加载细长 RC 柱的有力工具的有用性。还发现在升高的温度下展开对双曲率弯曲的柱具有不利影响。据观察，对于所有柱子，都存在临界偏心率，在此之后柱子对火的响应发生了变化。