The Numerical Simulation On Mechanic Behavior Of Core Steel-tube Reinforced Concrete Column Under Two-adjacent-surface Fire During Constant Loading

Core steel-tube reinforced concrete column is a composite structure of concrete-filled circular steel tubular surrounded with reinforced concrete, it is another modern kindof high load capacity composite column structure which is suitable for large span and highbuildings. And it is proposed to solve the complex node problem for concrete-filled steeltube and the bond failure problem for the SRC. It is necessary to analyze this new columnstructure because of the high frequency of modern architectural structure fires and thedifficulties of extinguishing fires. Since the barrier effect of the wall, the Core steel-tubereinforced concrete column under fire mostly belongs to the non-uniform fire situation,different from previous researches on the core steel-tube reinforced concrete column, thisarticle focus on the prism structure, mainly analyze the core steel-tube reinforced concretecolumn’s thermodynamic properties under the non-uniform fire situation of the adjacentsurface fire loading.The finite element analysis software ABAQUS is used here to simulate themechanical properties of the prism under fire. Simulation process is divided into roomtemperature loading, constant load firing and displacement loading three stages, includingthe axial compression basic model under room temperature and the thermal field model.Simulation of thermal field model belongs to the thermodynamic problem, by selecting theappropriate method which is suitable for solving the thermodynamic models and boundaryconditions, determining the thermal parameters of materials and applicable fire heatingcurve to complete simulation of thermal field model. After choosing the materialparameters, the model of core columns under room temperature in axial compression canbe successfully completed. On this basis, the overall model can be completed afterimporting the thermal field.This article mainly analyze the mechanical properties of the core steel-tubereinforced concrete column under the adjacent surface fire loading in axial compression,including ultimate bearing capacity, vertical displacement and the deflection’s analysis.,studies shown that steel tube yielding caused the damage of the column by analyzing the mechanical properties of the internal components. By changing the influence parametersof exposure time, coefficient of position, steel ratio, the longitudinal reinforcement ratioand axial compression ratio, the effects of different parameters on the ultimate bearingcapacity and the lateral deflection are discussed, the recommendations are also given tothe project.