Mechanical Performance Analysis Of Outsourced I-shaped Steel Column Foot

Steel structure column foot is the junction between foundation and superstructure,which plays an important role in the safety of structure.The column foot joints of steel structure mainly have three forms:exposed column foot,outsourced column foot and embedded column foot.Exposed column foot is mainly used in single-storey workshop,which has certain limitations in steel frame structure system.Outsourced column feet and embedded column feet are widely used in multi-storey steel frame structure systems.With the frequent occurrence of earthquakes at home and abroad,earthquakes have become an important factor affecting the safety of structures.More and more buildings pay more attention to setting reasonable column foot joints.The outsourced column foot can not only bear the vertical force transmitted by the superstructure well,but also play a better role in resisting the horizontal force.It is of great theoretical significance and engineering application value to study its mechanical performance,ultimate bearing capacity and failure mode.At present,there are relatively few researches on externally enclosed column feet in China,especially concrete externally enclosed H-shaped steel column feet.Therefore,this paper analyzes the stress characteristics of externally enclosed column feet through the large finite element software ABAQUS.Based on the finite element software to establish the appropriate finite element model analysis,this paper established a total of eleven outsourcing model type column foot,respectively from the setup outsourcing steel tube,outsourcing concrete thickness,height,axial compression ratio,whether to set the stud,etc.,discusses outsourcing type node stress performance,the influence of H steel column foot and column foot node failure mechanism,the result analysis shows that:The stiffness and ultimate bearing capacity of the column feet can be effectively increased by increasing the thickness of the outer concrete reasonably.The bearing capacity of steel column can be significantly improved by increasing the height of the outer concrete,but there is a reasonable value for the height of the outer concrete.For H-beam,the height of the outer concrete is 2.5d～3.0d(D is the height of the column section),which is a reasonable value range.The thickness of the outer concrete is reasonable between 160mm and 200mm.However,the setting of studs has little effect on the ultimate bearing capacity of the steel column.When the axial compression ratio increases,the ultimate bearing capacity of the steel column is also improved,and the stress in the compression zone and tensile zone of the steel column also changes significantly.It is beneficial to increase the bearing capacity of column foot to set square steel pipe in the outsourcing section.By setting different engineering parameters,this paper further studies and discusses the force characteristics of the H-beam column foot of the outsourced type,thus drawing some conclusions.The conclusions obtained in this paper can be used for reference in the future engineering design.