Numerical Analysis Of The Fire Resistance Behavior Of Composite Joint With Penetration Bars Of Concrete Filled Steel Tubular Column-Steel Beam

Most of the research on the fire resistance concentrated on column-through style joint, there is little research on the fire resistance of column-through style joint.So in this paper, The numerical models of the fire resistance for the composite joint with penetration bars of concrete filled steel tubular column-steel beam under the ISO834 standard heating curve is established, provides a basis for the design of the fire resistance of the joint.Firstly,this paper sets up temperature field model by choosing appropriate boundary conditions and suitable units and material constitutional relationships with ABAQUS, considering the effects of water vapor, using test to verify the correctness of model. Coefficient parameters of this model were analyzed.The following conclusions are obtained:(1) The temperature distribution is uneven, and the temperature field of joint is low except the concrete which near the steel bar,compared with field which away from joint.(2) The heating degree of reinforced presence can enhance node under fire, but the effect of diameter on the temperature field is not obvious.(3) The section width of steel beam has little influence on the temperature field of the joints.(4) Fire protection layer can significantly reduce the temperature of the joint in the fire.Secondly,this paper sets up finite element model of composite joint with penetration bars of concrete filled steel tubular column-steel beam in normal temperature with ABAQUS, using test to verify the correctness of model. Coefficient parameters of this model were analyzed.In order to provide the basis for the research of the fire resistance limit of the joint.In the end,this paper sets up model for the analysis of fire resistance of composite joint with penetration bars of concrete filled steel tubular column-steel beam with ABAQUS, using test to verify the correctness of model. Coefficient parameters of this model were analyzed.The following conclusions are obtained:(1) The load ratio has a great influence on fire endurance,the greater the load ratio the lower its fire endurance.(2) The axial compression ratio has a great influence on fire endurance,the greater the load ratio the lower its fire endurance.(3) The strength of reinforcing bar has little influence on the fire resistance.(4) The steel ratio has a great influence on fire endurance,the greater the load ratio the greater its fire endurance.(5) The fire protection layer will increase the fire resistance limit and increase the critical temperature.