Experimental Study On Axial Bearing Behavior Of Spatial Steel Frame Concrete Columns Embedded With Steel

The bearing capacity and its ductility of ordinary reinforced concrete columns can no longer meet the requirements of(super)high-rise buildings,more and more composite columns are used in engineering practice,such as steel reinforced concrete columns and concrete-filled steel tube columns and so on.On the basis of steel reinforced concrete columns and spatial steel frame concrete columns,a new composite column is proposed,namely the embedded steel spatial steel frame concrete short column,which is built in the space steel frame skeleton steel and pouring concrete.In this paper,a total of six specimens of five embedded steel spatial steel frame concrete short columns and one space steel frame concrete short column were subjected to experimental and finite element analysis under axial compression,and theoretical analysis was used to push out Computation Formula of Ultimate Bearing Capacity of Concrete Short Columns with Embedded Steel Spatial Steel Frames.A total of six specimens were designed with three parameters: the length of the angle steel limbs,the net spacing of the strips,and whether or not the steel was embedded.The axial compression test was conducted on a 5000 kN long column tester.During the test process,the morphological changes of the specimen during the entire loading cycle,the changes in the value of the strain gauge collection,and the ultimate bearing capacity were mainly observed.The load-displacement curves,load strain curve,and other mechanical properties were analyzed.Experiments have shown that increasing the length of the angle steel limbs and reducing the net spacing of the patch strips can increase the ultimate bearing capacity of the concrete steel spatial steel frame concrete short columns and improve the deformability.The finite element software ABAQUS was used to establish the nonlinear finite element model of the embedded steel spatial steel frame concrete short columns.Based on the verification of the test specimens,the length of the limbs,the width of the strips,the ratio of the ribs,the strength grade of the concrete,and the spacing between the strips were selected as parameters,and modeled and analyzed.Simulation analysis shows that reducing the spacing between the patch strips,the length of the limbs,the ratio of the bones,the width of the strips,and the strength grade of the concrete can improve the mechanical properties of the embedded steel spatial steel frame concrete short columns.In addition,the main factors affecting the mechanical properties of embedded steel spatial steel frame concrete short columns are obtained: the overall cuff factor.On the basis of experimental research and mechanism analysis,the constraints of the spatial steel frame on the core concrete were considered.The calculation formula for the ultimate bearing capacity of a spatial steel frame concrete short column embedded with steel has been deduced.The calculated results are in good agreement with the test results;it can provide a basis for the calculation of the axial pressure of the short columns.