Study on seismic behavior of FRP-confined steel reinforced UHPC composite columns

Abstract

In order to solve the disadvantage of poor seismic performance of steel-UHPC columns under a high axial compression ratio, three FRP-confined steel UHPC composite columns were designed and fabricated in this paper. The seismic performance of the composite column was studied by a quasi-static test. The final failure mode, load-displacement hysteresis curve and skeleton curve for each specimen were obtained. Then the seismic performance of the composite column is studied in terms of bearing capacity, ductility, stiffness degradation and energy dissipation. The effects of the axial compression ratio and the presence or absence of shear pins are analyzed. Experiments show that all specimens will eventually form plastic hinges at the column feet, leading to composite column failure. All specimens exhibited high residual bearing capacity, energy dissipation capacity and good ductility under horizontal hysteretic loading. The horizontal bearing capacity of the composite column can be increased by increasing the axial compression ratio and welding shear studs on the profile steel flanges.