Study On Axial Compression Behavior Of Slender Stone And Concrete Filled Steel Tubular Columns

Stone resources are abundant in the southeast coastal areas of China,and stone houses are mostly used in villages and towns.With the development of urbanization and the reconstruction of old houses,a large number of stone structure houses were demolished,resulting in a large number of stones.Stone has the advantages of high compressive strength and good durability,but it is prone to brittle failure when pressed.The research team proposed a kind of stone and concrete filled steel tubular(SCFST)columns,which placed the stone in the middle of the steel tube.Utilize the confinement effect of steel tube to improve the brittle failure of the stone,give full play to the compressive behavior of the stone,and increase the axial load-carrying capacity of the original concrete filled steel tube(CFST).In this paper,the axial compression behavior of slender SCFST columns are studied.Specific contents are as follows:(1)The axial compression behavior tests of 3 CFST columns and 9 SCFST columns were completed.The main research parameters were steel ratio ?,stone ratio ?and slenderness ratio ?.The effects of various parameters on specimen failure mode,load-deformation relationship,axial load-carrying capacity and deformation capacity are analyzed.The test results show that the specimen with a slenderness ratio of 11.3 occurs axial pressure failure and the specimen with a slenderness ratio of 25.8 occurs bending failure.Compared with CFST columns,the axial load-carrying capacity of SCFST columns is significantly improved,with a maximum increase of 87.2%.With the increase of the stone ratio,the axial load-carrying capacity of the specimen increases and the deformation capacity decreases.The axial load-carrying capacity and deformation capacity of the specimen increase with the increase of the steel ratio and decrease with the increase of the slenderness ratio.(2)The finite element model of SCFST column was established using ABAQUS software.The validity of the model was verified.The load distribution of steel tube,concrete and stone are analyzed during the whole loading process.The variation of the contact between steel tube and concrete and between concrete and stone with the loading process was studied.The research shows that with the increase of the stone ratio,the load of stone part is significantly increased,and its proportion of the ultimate load can reach up to 64.5%.The interaction of concrete with stone increases with the increase of stone ratio.(3)The ABAQUS software was used to analyze the parameters of the slender SCFST columns.The research shows that slenderness ratio from 12 to 60,the axial load-carrying capacity of the specimen decreased 34.4% maximum.The axial compressive strength of the specimen increases linearly with the increase of the yield strength of the steel tube,the steel ratio,the stone ratio and the compressive strength of the concrete.Based on the parameter analysis,the calculation formula of the axial compressive strength of the slender SCFST columns is proposed.