Parametric Study on Seismic Performance of FRP-RC Exterior Beam–Column Joints

A comprehensive and quantitative understanding of the seismic performance of fiber-reinforced polymer (FRP) reinforced concrete (FRP-RC) beam–column joints is still lacking. The issue is further complicated by a wide variety of FRP reinforcements. In this study, the challenge was investigated numerically and theoretically. A refined three-dimensional nonlinear finite element modeling approach was developed and validated against experimental results. The complex stress state of FRP reinforcements and the bond-slip behavior between FRP bars and concrete were reproduced. A total of 20 full-scale exterior beam–column joints were designed to quantify the effects of a series of parameters, including FRP type, beam shear–span ratio, the diameter of beam longitudinal bars, the diameter of beam-end stirrups, and the diameter and spacing of joint-panel stirrups. Satisfactory seismic performance was confirmed by the hysteretic responses of the specimens. The significant differences among the roles of the parameters were revealed. Especially, compared with their GFRP-RC counterparts, the ultimate loads and the related beam-end displacements of CFRP-RC specimens increased by up to 92.3% and 22.2%, respectively. Taking FRP type into account, a hysteretic model that can accommodate degradations in stiffness and strength was developed for the seismic design of FRP-RC beam–column joints.