Finite Element Analysis On The Mechanical Behavior Of The Embedded Concrete-filled Steel Tubular Column Base Joint

The column base joint is an important aspect in the structure design，It is also a key linkin the structure design. The research results and research theories of the column base joint arevery critical important for the development of the structure.So is the concrete-filled steeltubular column base joint.But until now the research on the concrete-filled steel tubularcolumn base joint is relatively few.So, It has realistic meaning for the concrete-filled steeltubular structure’s theory and application in developing research on such base joint.According to the experiment, this article builds the finite element analysis model of theconcrete-filled steel tubular column base joint with no reinforcement measures using theANSYS software.From the aspects of the ultimate load,load-midspan displacement and theperformance of the steel tubular and the steel, contrast the finite element analysis results andthe experimental results.Verify the rightness of the finite element model.Building the rightmodel.Then changing the parameters(the depth of the steel tubular,the ring’s thickness and thenumber of the stirrups) of the finite element model,this article studies the punchingperformance of the concrete-filled steel tubular column base joint which was buried in theconcrete foundation beam.The FEM analysis shows that: the concrete-filled steel tubular column base joint with noreinforcement measures will be destroyed as punching failure,the punching face appearedalong the ring board down. In punching region, the stirrups’ effect to punching shear strengthis obvious. when the model destroyed, stirrups in punching region have yield.The ANSYSanalysis the three aspects’s affection,the the depth of the steel tubular,the ring’s thickness andthe number of the stirrups.The results shows:the ultimate load of the column base joint is mostaffected by the the depth of the steel tubular and the number of the stirrups. the ring’sthickness affects less,and nearly nothing.On the condition of others unchanged,the ultimateload decrease as the depth of steel tubular gets deeper.,and the ultimate load increases as thenumber of the stirrups increase.Acorrding to the results of the FEM analysis and the affectionpoints of the ultimate load,this article modify the equation of the theoretical ultimate loadequation.Through contrast two types of joints, one type is the joint with no reinforcementmeasures,the other type is joint with different strengthen measure. The impression ofstrengthen measures to punching shear strength be discussed.If strengthen measures wereadded to the steel tube, such as studs、shearing ring、external annular steel plate, the punchingshear strength of the joints would be improved effectively.At last verify the effective of the joint with different strengthen measures from the economical way.