Study On Mechanical Properties Of Steel Tube Filled With Steel-reinforced Concrete Columns After High Temperature

As the building towards high-rise buildings, large scale and Multifunctional development, building fire becomes a higher frequency of disasters to people. In a building, bearing column is the main force bearing member which determine the safety performance of the building. Compared with Reinforced concrete column and Concrete filled steel tube column, Steel tube filled with steel-reinforced has better mechanical properties. At present, the research on Steel tube filled with steel-reinforced concrete belongs to the normal temperature and the research on its mechanical properties after fire is less.Using ABAQUS finite element analysis software to do the following research of the steel tube filled with steel-reinforced concrete composite column.(1)On the basis of past research, simulate axial compression under normal temperature and after the high temperature. And derivate the theoretical formula of the axial compressive bearing capacity under normal temperature and after high temperature based on the general theory. By contrast, found that the simulation value and the calculate value are in good agreement with each other.(2)Select the eccentric force, loading direction, and the temperature as the variable to analysis the component’s mechanical properties. Using stress cloud images to analysis the different stage of the Bias stress mechanism. The result shows that the capacity of strong axis loading is higher than the weak axis. The capacity of the column is not only decided by the loading direction when under eccentric loading. The other reason is the eccentricity, when the eccentricity is small; the capacity of the composite column under the strong axis loading is much larger than the capacity under the weak axis loading. When the eccentricity is big; the capacity of the composite column under the strong axis loading is little higher than that of the weak axis loading. And on the basis of axial compression formula, get the Bias formula after high temperature by introducing the coefficient. And the simulation value has a good agreement with the theoretical value.(3)Select the slender ratio, structural steel index and the temperature as the variable to analysis the column’s stability capacity. The result shows that with the increase of slender ratio the capacity of the composite column is decreasing. The ductility of the column increases with the increase of Structural steel index. And the capacity decreased with the increasing of temperature. And establish the formula to calculate the stability capacity under axially compression and the eccentric force after high temperature. The simulation results and the calculation results are in good agreement.