Temperature Field Calculation And Application Of Concrete Filled Circular Steel Tubular Column

Fire is one of the most numerous and destructive disasters among all kinds of the disasters. The economic loss it brings directly is only less than drought and flood, and especially in recent years, the frequency of it is the first of all kinds of disasters. Because buildings become high stratification cosmically and complex they are used, factors that lead to fire increase along with them. The dimension of fire also enlarge with them, building fire-resistance arouse people more and more regard, so it is very important for people to seek for the new type of structure that strongly resisting fire.CFST (concrete filled steel tubes) is a new type structure between steel and reinforced concrete. CFST utilize the mutual restriction of material steel and concrete, and make up the shortage of them, so the virtue of the two kinds of material can be exerted. Therefore CFST not only has predominant mechanical performance but also good fire resistance.The carrying capacity of CFST under high temperatures (fire) will be reduced with the temperature's raise. In order to obtain the fire resistance of CFST, the temperature field of CFST under high temperature must be determined. A set of academic analysis aimed to know mechanics of concrete filled circular steel tubular columns subjected to fire are carried out in this paper. The main contents as follow:Summed up research findings on thermal properties and mechanics of steel and concrete under high temperature inside and outside of country. Based on it, the thermal properties and heat mechanics of steel and concrete that composed concrete filled circular steel tubular columns are given. And stress-strain relation models of steel and core concrete are established. The interaction between steel and core concrete is taken into account sufficiently by these models.Finite element model for the calculation of the temperature fields of concrete filled steel tubes have been set up. And a comparison between calculated results using this model and testing results has done is a good agreement.The theoretical model for calculating fire resistance of concrete filled circular steel tubes is determined. Fire resistant limit of concrete filled circular steel tubes and influence of parameters on fire resistance is analyzed.