Experimental Research On Push-down Test Of RC Exterior Beam-column Connection At High Temperature

Fire accidents do not only cause great damage to buildings,but also lead to loss of life.Therefore,it is in urgent need of study and evaluation on the safety of building structures under the fire and after fire,in order to minimize damage of society.The current high temperature research results focused on mainly reinforced concrete(RC)materials and components.The experimental study on progressive collapse of beam-column joints of RC frame structure were confined to room temperature,to this end,beam-column side joint substructures under vertical push-down experiments were carried out,and the mechanical behaviors of beam-column side joint substructures under high temperature and after high temperature were acquired.The main research was summarized in detail as follows:(1)The push-down tests of RC side beam-column joints were carried out at room temperature and the regularity of development of load-displacement curves,horizontal axial force,bending moment of cross section,and strain of steel bar were obtained.Research was conducted to investigate the influence of different anchorage form on the static performance of substructure,such as vertical bearing capacity,ductility,energy dissipation,the maximum value of axial force and bending moment capacity.(2)The push-down tests of RC side beam-column joints were carried out at high temperature and after temperature and the regularity of temperature field,development of load-displacement curves,horizontal axial force and bending moment of cross section were obtained.Research was conducted to investigate the influence of different anchorage form and different heating time on the static performance of substructure,such as vertical bearing capacity,ductility,energy dissipation,the maximum value of axial force and bending moment capacity.(3)By comparing test results under room temperature and high temperature,the mechanical performance of RC side beam-column joints were summarized,and the research will provides the test data and design reference for anti-progressive collapse RC frame structure.