Study on axial compression ratio limit of concrete-filled steel tubular composite column with T-shaped steel flange
In order to fully utilize the deformation performance of concrete-filled steel tubular composite column with T-shaped steel flanges(T-CFST column)and ensure that the columns can meet the ductility requirements under seismic action,the ductility and axial compression ratio limits of the T-CFST columns were investigated by theoretical derivation and numerical simulation.Based on the critical failure state between large eccentricity failure and small eccentricity failure,the formulas for calculating standard axial compression ratio and design axial compression ratio of T-CFST column was proposed.Based on the ABAQUS software,a refined finite element model of the T-CFST column was established.After verifying the accuracy of the finite element model,the influence of various influencing factors on the ductility of composite columns under high axial compression ratio was studied.The design axial compression ratio limits of composite columns under various steel ratios,steel strength and concrete strength were suggested.The results show that the ductility of T-CFST column increases with the decrease of concrete strength,the decrease of section steel ratio,the increase of steel strength and the increase of volume hoop ratio.Even at a large axial compression ratio,the ductility of the column is still good,and the limit of the axial compression ratio of the T-CFST column is allowed to be increased on the basis of calculation.
composite columnductility performancenumerical simulationtheoretical calcula-tionaxial compression ratio limit