Temperature Distribution In Concrete Filled Steel Tube Columns Under Pool Fire

With the development of modern architecture, the building structures are more complicated, and the building materials for it are rigorous than anymore. So concrete filled steel tube column is need more because of its advantages. Therefore, the research of the thermal behavior of under fire is significant. The main content of this paper is temperature distribution in it under pool fire.This paper does experiments about the temperature distribution in concrete filled steel column under pool fire, based on the ISO9705bench. The n-heptane fire can be in open space and confined space. In order to simulate different fire scene, the paper changes the size of sump and the weight of n-heptane. In the experiment, the concrete filled steel column is surrounded by the fire. Analyzing the experimental results, the paper summarizes the law of the temperature distribution.Firstly, the paper researches the temperature distribution in cross-section, the longitudinal external and the longitudinal internal, taking HS3for example. In the HS3, oil pan size is60cm×60cm, the weight of n-heptane is10kg, the fire is burned in open space. In the experiments, the size of the sump is40cm×40cm、50cm×50cm、60cm×60cm、70cm×70cm、80cm×80cm, the weight of n-heptane is10kg、15kg、20kg. Considering the fire dynamics factors, the effects of heat release rate, burning time to the temperature distribution are studied, by comparing the experimental results.When comparing the temperature distribution in open space and confined space, the size of sump is40cm×40cm、60cm×60cm、80cm×80cm, the weight of n-heptane is10kg. Considering the heat transferring way and the fire burning characteristics in confined space, the effects of thermal feedback and ventilation to the temperature distribution are studied, by comparing the experimental results.The results show that the temperature distribution in longitude and cross-section of the concrete filled steel tube columns both has significant temperature gradient, and the external temperature is very much affected by heat release rate, while the internal temperature is mainly affected by the burning time. Besides, the maximum temperature difference in external concrete reached110℃. And the temperature distributions are clearly different in confined space and open space, the difference is decided by the heat release rate and the hot gas layer.