To evaluate the fire resistance of a structural member, the temperature profile in the cross section of the member needs to be obtained first. Full-scale fire tests have not been conducted on floor systems with steel-plate composite structures, termed SC floors. The traditional finite element analysis does not yield reliable temperature predictions in the steel and concrete of the SC floor under a standard fire. In this paper, the effective thermal properties of concrete in an SC floor are proposed for evaluating the transient temperature field according to the special heat transfer mechanism found by test data. The validity of these effective thermal properties is established by incorporating them into a finite element model and comparing the temperature predictions with data from fire tests. It is shown that the proposed effective thermal properties of concrete provide a good prediction of the temperature field in an SC floor under fire. The derivation process of the effective thermal properties based on the heat transfer analysis makes it possible to expand the scope of its application when the situation is similar to an SC floor.

为了评估结构构件的耐火性，首先需要获得构件横截面的温度曲线。尚未对具有钢板复合结构的地板系统（称为SC地板）进行全面的防火测试。传统的有限元分析无法在标准火灾下对SC地板的钢和混凝土中的温度进行可靠的预测。本文根据试验数据发现的特殊传热机理，提出了一种SC地板混凝土的有效热性能，以评估瞬态温度场。这些有效的热性能的有效性是通过将它们合并到有限元模型中，并将温度预测与火灾测试的数据进行比较来确定的。结果表明，所提出的混凝土有效热特性可以很好地预测着火条件下SC地板的温度场。当情况类似于SC地板时，基于传热分析的有效热特性的推导过程可以扩展其应用范围。