Experimental Study On Seismic Behavior Of Double Spatial Steel Frame Concrete Columns

As a kind of hollow section shape of steel reinforced concrete structure,research group have carried out a lot of spatial steel frame concrete structure experiment of static performance and seismic performance.The test results have shown that core concrete constrained by the spatial steel frame have a better binding effect,results in a significant improve on mechanical properties of concrete.Based on the study of research group,this paper proposed a new kind of composite column named double spatial steel frame concrete column which were formed by buried spatial steel frame concrete within spatial steel frame concrete column.By the means of experimental study and element finite analysis under cyclic loading of low loop,this paper explore the seismic behavior of the double spatial steel frame concrete column.7 double spatial steel frame concrete column specimens were designed and casted steel ration?the external chord limb length of spatial steel frame?,axial compression ratio,the external forms of steel skeleton,the buried forms of steel skeleton etc.as design parameters.The seismic performance experiment of the double spatial steel frame concrete column was carried out.The test results show that double spatial steel frame concrete column has a high bearing capacity.Its hysteretic curve is full,no draw shrinkage with good capacity of ductility and dissipating energy.The peak laod and deformation capacity of double spatial steel frame concrete column specimen were increased,as the external chord limb length increased.The double spatial steel frame concrete column models which was same with the experiment factors were established by the means of the finite element analysis software ABAQUS.Based on accordance with the results of experiment,this paper do multiple sets of simulation parameters analysis,such as within and outside steel ration and stirrup ratio,axial compression ratio,the external forms of steel skeleton,etc.The simulation results show that the bearing capacity and ductility of the double spatial steel frame concrete column were increased,as within and outside chord?angle?limb length and thickne increased,or the width of the transverse lacing bar increased,or axial compression ratio decreased,and the spacing the transverse lacing bar decreased.On the basis of the experimental study and simulation analysis,this paper explore constrain mechanism of core concrete constrained by the double spatial steel frame.The analysis results show that the confinement index of spatial steel frame concrete???can reflect the binding effect of core concrete constrained by double spatial steel frame.The bearing capacity of the double spatial steel frame concrete column under cyclic loading of low loop,which is approximately linear related to the the confinement index of axial compression ratio?n?,within and outside steel ration(?_cc),the external spatial steel frame concrete??₁?and the the confinement index of the buried spatial steel frame concrete??₂?.