Research On Mechanical Properties Of Concrete-filled Steel Tubular Columns With Ring Under Axial Compression

The composite concrete-filled steel tubular(CFST)column with reinforced ring consists of composite concrete-filled steel tubular column and reinforced ring.The composite concrete-filled steel tubular column is a new type of composite column,which is characterized by the construction of double-layer steel pipe and filled with concrete.It has the advantages of good energy dissipation performance,high load-carrying capacity,saving the template and so on.Based on the fact that the present experimental research and numerical analysis is not enough and the existing design rules of the composite structures are still not perfect,this paper is mainly about the numerical analysis of the composite CFST column with reinforced ring.In this paper,the axial compressive mechanical behavior of composite CFST column with reinforced ring is studied.A total of 96 models and 18 sets of comparative analysis models are established by ABAQUS.And the analysis on the parameters influence of the axial compressive mechanical properties is made after that.Finally,on the basis of predecessors,the formulas for calculating the axial load bearing capacity of the composite CFST column with reinforced ring are summarized and validated,which has its own academic value for the theoretical system of the composite CFST column with reinforced ring.And it also provides the reference for design and the theoretical basis for practical engineering.The main work of this paper includes:(1)Analyzed the working mechanism of the composite CFST column and compared the axial compressive bearing capacity stress-strain curves and failure processes of the finite element of the composite CFST columns and that of the experiments using the same parameters.It validated that the results of the finite element model analysis has its reference.The main work of this paper is:(2)Took the thickness of outer steel tube,the thickness of inner steel tube,the strength of concrete and the thickness of steel ring-ribbed slab as the variable parameters to analyze the axial bearing capacity and compared the influence the of each parameter.At the same time,the failure mechanism of each component of the specimen including force transmission mechanism and bearing capacity is studied.(3)Based on the rich previous theoretical research and finite element analysis results,the formulas for stiffness and axial load bearing capacity of composite CFST column with reinforced ring are summarized and validated.According to the finite element analysis of the control model,the paper calculated the influence on the axial compressive bearing capacity when the ratio of inner diameter to outer diameter varied from 0.1 to 0.9.In the meantime,the applicability and reliability of the formula is examined.