| The steel-concrete composite structure is increasingly widely used in modern high-rise buildings.Its fire resistance performance is concerned with the safety of people's life and property,so more and more attention has been paid to it.The fire resistance of steel-concrete composite structure is further discussed and suggestions for improvement of fire protection structure are put forward.It has great and far-reaching significance for popularizing and improving the theoretical research system of fire resistance of steel-concrete composite structure.Many influential factors have resulted in many difficulties in the fire test and then the advantages of the finite element method began to embody.This paper is based on a large number of predecessors' theoretical and experimental research and large finite element software ABAQUS.I established the finite element of steel reinforced concrete columns and steel reinforced concrete column steel concrete composite frame beam model.Then the numerical simulation and analysis of the temperature field and mechanical properties of high temperature are carried out respectively.The main contents and results are as follows:(1)Based on the research results of related domestic and foreign steel and concrete's thermal performance and steel reinforced concrete structures' mechanical properties at high temperature,selecting the thermal performance parameters of steel and concrete and the mechanical properties of steel concrete at high temperature for this study.And then carried out analysis of temperature field of steel reinforced concrete columns under different fire conditions.The results show that the temperature distribution of the cross section has great influence on the temperature distribution of the cross section and the temperature lag effect is obvious in the medium steel concrete column under fire.(2)In the selection of steel and concrete's thermal performance and steel reinforced concrete's mechanics performance parameters under high temperature,carried out the calculation of bearing capacity under normal temperature,temperature field and mechanical properties under high temperature of twelve type steel reinforced concrete columns.The influence of parameters such as section size,steel ratio,reinforcement ratio,axial compression ratio,slenderness ratio and load eccentricity on the fire resistance of steel concrete columns is studied.The conclusions are as follows: section size,steel ratio,axial compression ratio,slenderness ratio and load eccentricity have great influence on fire resistance of steel reinforced concrete columns,while the fire resistance of steel reinforced concrete columns is limited by reinforcement ratio.(3)A steel reinforced concrete column and steel-concrete composite beam frame model with two layers and two span is built.Based on the thermal performance and constitutive relation of steel and concrete,the temperature field of the frame under various fire conditions is investigated.The fire resistance of the composite frame under different fire and load conditions is analyzed from two aspects of displacement deformation and internal forcevariation.The result is that the fire location and the protection of the distribution of the whole set layer composite frame temperature influence,while the temperature transfer law and single member conditions were similar.The axial compression ratio,the condition of fire and fire duration on the overall framework of fire resistance is greatly affected. |
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