Working Mechanism Of New Square Concrete-filled Steel Tube Composite Column

The new Square Concrete-Filled steel Tube composite Column(SCFTC),which insert strengthened ribs into the square steel tube and pour concrete into it.The new SCFTC has high ultimate load capacity,good ductility and seismic performance,etc.The new composite columns can meet requirements of large span,heavy load in modern engineering structures.Based on summarizing experiments and finite element simulation about square composite column and relevant composite column,SCFTC is proposed in this paper and structural behavior and capacity calculation methods of the SCFTC are studied under axial compression and eccentric compression loads.The main contents of this paper are as follows:(1)ABAQUS software is used to carry out nonlinear finite element analysis of SCFTC under axial and eccentric compression loads.On this basis of verifying the feasibility of the model,the working mechanism of the new SCFTC is analyzed including failure modes,load-deformation curves of the whole process,stress and strain of concrete and steel tube,other aspects.Comparing results with square concrete-filled steel tube column show that SCFTC has good mechanical properties.(2)Considering the relevant parameters of the new combination that is affected load-deformation curve,including the strength of steel and concrete,the width and thickness of the ribs,width-to-thickness ratio and eccentricity,the key parameters affecting the performance of the SCFTC are defined.Mechanical properties of SCFTC with shear connection are analyzed.The arrangement density and length of the shear connection affecting load-deformation curves of new composite column are studied.(3)Based on the parameters analysis,bearing capacity formula of SCFTC under axial and eccentric compression is derived using theory and regression analysis methods.The formula is compared with the public test results and formulas in the literature,verifying the practicality and reliability of the proposed formula in this paper.The research work can provide reference for practical engineering.