Abstract Previous studies of concrete-encased concrete-filled steel tube (CFST) columns have demonstrated their enhanced fire performance due to the passive protection of the outer encasement. To facilitate the design and application of concrete-encased CFST structures, the fire performance of full-scale reinforced concrete beam to concrete-encased CFST column joints subjected to full-range fire including heating and cooling phases was studied experimentally. This paper presents the experimental programme and reports the experimental results related to temperature. Finite element analysis (FEA) models of varying complexities were also incorporated to complement the fire tests and to better interpret the temperature developments. Results show that beam failure was observed for all tested specimens. Concrete explosive spalling was insignificant due to the low strength of the outer concrete. The temperature of the joint zone was tremendously reduced compared to the connected members due to the passive protection of outer concrete and the heat sink effect. For the region close to the steel tube, the temperature-time curves showed a significant moisture plateau. The FEA models produced satisfactory temperature predictions when the thermal properties in Eurocode 4 were used.

中文翻译：

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钢管混凝土柱与钢筋混凝土梁组合节点温度变化的试验与数值研究

摘要 先前对钢管混凝土 (CFST) 柱的研究表明，由于外包装的被动保护，它们增强了防火性能。为便于钢管混凝土结构的设计和应用，试验研究了全尺寸钢筋混凝土梁与钢管混凝土柱节点在全范围火灾（包括加热和冷却阶段）下的防火性能。本文介绍了实验程序并报告了与温度相关的实验结果。还结合了不同复杂性的有限元分析 (FEA) 模型，以补充火灾测试并更好地解释温度发展。结果表明，对于所有测试样品都观察到梁失效。由于外层混凝土强度低，混凝土爆炸剥落不明显。由于外部混凝土的被动保护和散热器效应，与连接构件相比，连接区的温度大大降低。对于靠近钢管的区域，温度-时间曲线显示出显着的水分平台。当使用欧洲规范 4 中的热属性时，FEA 模型产生了令人满意的温度预测。