The Failure Anslysis Of Space Steel Frame Structure In Fire

The progressive collapse of structures has become a serious threat to public safety at present,thus this problem has received increasing concern.The research on progressive collapse has been carried out for more than 30 years abroad,and some design and analysis methods of structure progressive collapse resistant was put forward.Since the 9 · 11 incident,the progressive collapse caused by fire attracts more attention.Fire,as the abnormal incidents,has the particularity of long time,large scope,so design and analysis methods that only focus on the structure reaction caused by the damage of partial key component,isn’t suitable for the calculation and analysis of structure progressive collapse resistant under fire.Steel can be applied to many different kinds of high-rise and large span structures due to its advantages such as the high strength,the light weigh,the great plasticity and toughness.With the development of steel structures,the fire resistance ability of steel frame is increasingly paid more and more attention.However,because of the high experimental expense and the limitation on the test equipment,the experts at home and abroad put their attention to the data simulation and make research for thirty years.During the time,they come up with many valuable design method and analysis ways.The whole process of steel frame suffered from fire is simulated based on the ANSYS finite element software.We establish the heat transfer model of the steel frame under fire condition to study the overall fire-resistant in fire,and the material non-linearity and the geometry non-linearity are considered synthetically.The main contents of this paper can be summarized as follows:1.Based on the selected physical parameters,the temperature field of structures is calculated and obtained according to the ISO834 standard fire-temperature curve.2.The stress field of steel frame structures based on practical static load and the weight of the structure itself is calculated by ANSYS progress.And the temperature field of steel frame structures was put into the structure progress by the coupling method of ANSYS to obtain the failure analysis.3.The parametric study analysis was carried out to determine the effect of fire location,fire column of form,ratio of linear stiffness of beam and column on the deformation during overall fire process of heating.The main conclusions are as follows:1.The structure usually collapses in the beginning of the damage of the beam in the condition of the fire column in one-side.The lateral displacement of column exceeds the allowed values due to lack of constraints.2.As the column is under fire in all directions,the column is destroyed by the high temperature,that is more dangerous situation.3.The change of column constraint was different when ratio of linear stiffness of beam and column was changed,but the failure time of structure was not much changed.