| The circular steel tubular concrete column is widely used in modern engineering construction because of its excellent performance.In engineering,the member mainly bears the vertical load,but also bears the transverse shear force and bending moment under the action of horizontal wind load.At present,there are few researches on CFST column members at home and abroad,and most of them are rectangular CFST members.Therefore,in this paper,the shear resistance of the circular steel tubular concrete column under the action of transverse shear force and vertical axial force and transverse shear force is deeply studied by finite element simulation.The research work is as follows:(1)In this paper,ABAQUS/CAE 2020 is used to establish the nonlinear three-dimensional tensile solid round steel tube concrete shear model.The constitutive relationship of concrete adopts the triaxial damage plastic constitutive model,and the constitutive relationship of steel adopts the elastic-plastic(hardening)constitutive model.Firstly,a full scale finite element model of CFST column was established based on the experiments of other scholars at home and abroad,and the analysis results were compared with the experimental data of other scholars to verify the correctness of the modeling method and the constitutive relationship.Using reasonable modeling method,the pure shear model of circular steel tubular concrete column was established to analyze its parameters and determine its limit shear span ratio,and the influencing factors such as steel strength,concrete strength,construction steel ratio,component section size and component length were simulated and analyzed.Through the simulation calculation of a large number of models,the shear constraint action of CFST column and the proportion of external steel tube and core concrete under pure shear state are analyzed,and the difference of shear performance between steel tube and empty steel tube and core concrete and plain concrete is compared.The interaction between CFST members under shear condition is revealed.To force based on the superposition principle of material mechanics,the external steel tube with internal core concrete assume their respective shear,puts forward the round steel tube concrete column under the pure shear state formula of shear bearing capacity,and the formula with other scholars put forward the formula and related specification formula at home and abroad,to verify the accuracy of the formula.(2)ABAQUS/CAE 2020 was used to establish a three-dimensional tensile solid finite element model of round steel tubular concrete column under the combined action of vertical load and transverse shear force.The constitutive relations of concrete and steel were the same as those under pure shear state.The compression shear model of round steel tubular concrete column was established based on the experimental schemes of other scholars at home and abroad.The correctness of the modeling method was verified by comparing the calculated results with the experimental data.The influence of two different loading paths of shear before compression and compression before shear on the shear capacity of components was analyzed and compared.Finally,the loading mode of shear before compression was determined to carry out subsequent modeling calculation.Through modeling calculation,the failure mode and combined action mechanism of CFST column under compression and shear action and the proportion of steel tube and concrete bearing shear force and axial pressure are analyzed.The influence of concrete strength,steel strength,steel ratio,shear span ratio and other factors on the shear capacity is analyzed.Based on the nonlinear fitting of parameter relation curves,a formula for calculating the shear capacity of circular steel tubular concrete columns under compression and shear is proposed,and the accuracy of the formula is verified by comparing it with other formulas. |
PDF Full Text Request