Analysis Of High Temperature Effect About Concrete-filled Steel Tube Axial Compression Column

Fire disasters are increasingly becoming the head of the community's life and property caused great harm. Bridge and Structural fire has been gained attention in all aspects, so research and find the structural and fire resistance is very important.Steel concrete structure is a new type of composite structure. Its mechanical characteristics between steel and concrete interaction, the development of steel tube confined concrete aspect, the axial bearing capacity of concrete, the ductility has increased. Superior mechanical properties of the two materials alone.Steel concrete columns under fire load capacity decreases with prolonged fire, but still better than the carrying capacity of the structure formed by two materials, a separate carrying capacity. Therefore, the study section of concrete filled steel tubular column temperature distribution is the key. In this paper, concrete filled steel tube columns under fire conditions, the mechanical properties and fire resistant design methods theory. Specific job description is as follows:(1) A comprehensive introduction of the steel and concrete thermal performance of the two materials and mechanical performance, which determine the steel and concrete in fire conditions, the thermal performance indicators and targets and the mechanical properties of steel-concrete composite structures of two Material force of a thermal coupling between the constitutive model, the model considers the interaction between the steel and concrete.(2) The systematic summary of concrete and steel at home and abroad on the basis of thermal parameters, calculated by the finite element method in the fire tube section of concrete columns in the distribution and variation of temperature trends and explore the impact of cross-section temperature field of a variety of factors, including:concrete type, section size and steel thickness of the protective layer. Based on calculations show that the theoretical calculations and experimental results are in good agreement.(3) Determine the tube concrete columns under fire conditions, theoretical analysis model, the circular steel tubular column under fire on the impact of carrying capacity and fire resistance of concrete filled steel tube column parameters were analyzed. Components found by calculating the steel ratio, steel yield strength, concrete strength, section size and the slenderness ratio of the steel components of concrete column after high temperature mechanical properties of the larger, protective layer should be relatively less affected.Conclusions drawn from the analysis in this paper, this type of fire-resistant design of concrete filled steel tubes have some reference.