Evaluation of axial compressive performance of FRP-confined steel-reinforced concrete column-to-reinforced concrete ring beam joint with seismic damage

Axial compressive tests were conducted on two fiber reinforced polymer (FRP)-confined steel-reinforced concrete (FCSRC) column-to-reinforced concrete (RC) beam joints with seismic damage which have different reinforcement ratios of the ring beam. The axial compressive performance of the specimen with seismic damage was analyzed and evaluated by finite element simulation and theoretical analysis. The results show that the failure of the specimens is caused by the rupture of the glass fiber reinforced polymer (GFRP) tubes, indicating that the designed specimens still meet the design principle of strong joint and weak members after seismic. When the ring beam reinforcement ratio is increased from 1.4% to 2.5%, the yield load and initial stiffness of the specimen do not change much, while the peak load and post-yield stiffness increase by 7.3% and 60.2%, respectively, and the ultimate deformation and ductility factor decrease by 10.4% and 8.5%, respectively. The established finite element model can better reflect the axial compressive behavior of the specimens with seismic damage. The proposed theoretical formulation could predict the axial compressive bearing capacity of the specimen with seismic damage accurately with certain safety reserves. © 2022, Editorial Office of Acta Materiae Compositae Sinica. All right reserved.