| The slab-column structure is mainly composed of floor slab and column.Compared with the traditional frame structure,the slab-column structure has the advantages of high and low stories and flexible space arrangement,but the slab-column structure also has its shortcomings.The reinforced concrete slab-column structure is prone to punching and shearing damage.Fire is the most frequent and common disaster that threatens public safety and social development.One of the harms.When fire occurs,punching failure occurs when the bearing capacity of slab-column structure decreases.When punching failure occurs at a certain joint,it will cause redistribution of internal force,and consequently cause continuous collapse of slab-column structure.In this paper,the edge joints of reinforced concrete slab-column structure are taken as the research object,and the edge joints of slab-column structure are deeply studied.The main research work is as follows:1.The punching shear resistance of edge slab-column connections at room temperature is studied and analyzed.In this paper,the punching shear resistance of edge slab-column connections is simulated by ABAQUS finite element software.The accuracy of the model is determined by comparing the simulation results and the output cloud images with the experimental phenomena.On the basis of determining the model accurately,the reinforcement of concealed beam is added to the member.The reinforcement of concealed beam which is consistent with the reinforcement of concrete slab is used as the reinforcement of concealed beam.The improvement of punching shear resistance and penetration performance of concealed beam reinforcement to slab-column structure is studied by different reinforcement ratio of concealed beam.The simulation results show that the concealed beam reinforcement can share part of the Ioad,improve the bearing capacity of edge slab-column connections,and effectively improve the punching shear resistance of edge slab-column connections.2.The temperature field of slab-column edge joint is simulated.On the basis of summarizing the thermal performance of reinforced concrete materials,the analysis model of edge slab-column connections at high temperature is established by using ABAQUS finite element analysis software,and the fire simulation analysis of edge slab-column connections is carried out.According to the ISO-834 international standard heating curve,the component is heated.The natural temperature of the room is 20 C.After three hours of heating,the temperature of the fire surface at the bottom of the middle plate of the plate-column edge joint reaches more than 1000 degrees Celsius,while the temperature of the non-fire surface at the top of the plate is only about 30 degrees Celsius.Through the analysis of temperature field of edge slab-column connections,pave the way for the thermo-mechanical coupling analysis of edge slab-column connections.3.Coupled thermo-mechanical analysis of plate-column edge joints.On the basis of determining the thermal properties and temperature field analysis of reinforced concrete materials,the thermal-mechanical coupling calculation model of reinforced concrete edge slab-column connections at high temperatures is established by using ABAQUS software,which is consistent with the normal temperature model.The punching shear resistance of edge slab-column connections at high temperatures is simulated and analyzed.At the same time,the reinforcement of hidden beams is added to slab-column structures for comparative analysis.From the analysis results,it can be seen that under high temperature conditions,hidden beam reinforcement can effectively improve the punching shear resistance of edge slab-column connections.According to stress contour plot,hidden beam reinforcement bears part of the load,improves the bearing capacity of edge slab-column connections,delays the punching shear failure time of slab-column joints,and the higher the reinforcement ratio,the greater the load shared by hidden beam reinforcement.This shows that adding hidden beam reinforcement effectively improves the punching shear resistance of edge slab-column connections,and provides some reference for future fire resistance research of slab-column structures. |
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