Study On Calculation Model Of Collapse Of Steel Frame Column

Steel frame column as a key bearing structure of steel frame structure,has a very important impact under the action of the collapse of the steel frame.Therefore,it is very meaningful to clarify its damage evolution law and collapse mechanism under the action of earthquake,and to evaluate its damage degree under earthquake action for the anti-collapse design of the whole frame structure.In this paper,the part that from the post-bending point of the steel frame to column feet is selected as the object of study,ABAQUS / Explicit is used to establish the fine finite element model of material constitutive based on damage evolution and failure.Static non-linear analysis(Pushover analysis)of steel frame column is carried out.The main research contents and achievements are summarized as follows:1.The existing experiments has been simulated to verify the correctness and scientificity of the refined finite element analysis method based on the material damage constitutive.That shows the method of fine-grained finite element analysis based on material damage constitutive is feasible.2.Some cantilever columns of I-shaped and box section that conform to the specification requirements has been designed,and the whole process of the damage of those columns under constant vertical axial force and lateral monotonic load is simulated in order to clear the failure mechanism of steel frame column.The damage law and failure state of the steel frame column under different axial compression ratio,flange width and thickness ratio,web height to thickness ratio or wall thickness ratio are analyzed by using the deformation diagram and the column top load-displacement curve.And the deformation characteristics of the steel frame column are analyzed according to the bending moment curve.3.We analyzed the results of the refinement explicit finite element simulation,and proposed a centralized plastic hinge model for the steel frame columns which are suitable for China’s steel and can be used for the whole process of collapse.The model of the centralized plastic hinge is calculated by SAP2000 custom hinge properties.And we compared the results with the ABAQUS refinement model,the correctness of the plastic hinge model is verified.In the future,it is necessary to use the plastic hinge model to analyze the seismic behavior of steel frame columns by using the SAP2000 custom hinge properties.This greatly improves the accuracy and efficiency of Engineering design and realizes the application of the fine analysis results in the simplified seismic design.4.Based on the plastic hinge model,the performance point is found,and the criterion of seismic damage grade of steel frame column with broken bending is obtained with reference to the "Building Structure Anti-collapse Design Code".The standard can be used in the actual design to preliminarily evaluate the anti-collapse ability of the steel frame column in order to get the target " Big earthquake does not fall" of steel frame column.