Research on Seismic Performance of Concrete-Filled Square Steel Tubular Columns with CFRP Profiles

In order to investigate the seismic performance of concrete-filled square steel tubular columns with CFRP(C-CFST), three columns with CFRP were tested under quasi-static load with steel ratio as the parameter. The changing parameter of the composite columns is steel ratio. The loading process and failure modes of the composite columns were described. ABAQUS finite element analysis software was used to establish a numerical analysis model on the basis of rational selection of material constitutive relations. Compared with the experimental results, the accuracy of the model and its modeling method were verified. By establishing a large number of refined numerical models, considering different parameters such as yield strength of steels, compressive strength of concrete, steel ratio, slenderness ratio, and whether I-shaped CFRP profiles are built in, the influence of these parameters on the load-displacement hysteretic curve, load-displacement skeleton curve, stiffness, bearing capacity and other performance indicators of composite columns was studied. The results showed that the hysteretic curve of the new composite column was relatively full, there was no obvious pinch phenomenon, and it showed a good seismic performance; compared with ordinary CFST tubular columns, the new composite columns had better ductility, bearing capacity and energy dissipation capacity; the change of concrete compressive strength had little effect on the ultimate bearing capacity of composite columns, and the ultimate bearing capacity would increase significantly with the increase of steel yield strength and steel ratio; when the wall thickness of square steel pipe increased by 1 mm, the ultimate bearing capacity increased by 14.3%, 8.3%, and the energy dissipation value increased by 14.3%, 10.7%; when the slenderness ratio increased from 32.33 to 50.81, the ultimate bearing capacity and energy dissipation decreased by 41.2% and 60.8%, respectively. Therefore, it is suggested that the slenderness ratio should be reasonably controlled.