In order to evaluate the seismic performance of large-rupture-strain fiber reinforced polymer (LRS FRP) confined non-ductile reinforced concrete (RC) square columns under earthquake action

quasi-static experiments were carried out on seven FRP-strengthened RC square columns

including a reference column

a carbon FRP (CFRP)-strengthened column

and five LRS FRP-strengthened columns. The failure modes

seismic performance parameters

and FRP strain of specimens were analyzed

and the effects of FRP types and fiber thicknesses on the failure modes and seismic performance of different specimens were studied. Results show that under axial load and cyclic lateral load

the cover concrete of the reference column in the plastic hinge zone was peeled off and crushed

and the longitudinal bars were severely buckled

while the FRP-strengthened columns did not experience concrete spalling or FRP rupture

indicating that FRP reinforcement changes the failure mode of non-ductile column. Compared with the reference column

the application of FRP significantly improved the ductility and energy dissipation capacity of the RC columns

while the increase in the maximum horizontal bearing capacity was marginal. FRP reinforcement decreased the strain of the longitudinal bars and stirrups

and prevented the buckling of the longitudinal bars. Compared with the CFRP-strengthened column

the large-rupture-strain advantage of LRS FRP was not obvious. The main reason was that the axial load ratio was low and the slenderness ratio was high in this study

so that the compressive area of the FRP confined concrete in the plastic hinge zone was small. Based on the stress-strain model of LRS FRP-confined concrete developed on OpenSees software platform

the experimental results were simulated

and the simulated curve agreed well with the experimental curve

which verified the accuracy and reliability of the model in the seismic analysis of FRP reinforced columns.