Behavior of geopolymeric recycled aggregate concrete-filled FRP tube (GRACFFT) columns under lateral cyclic loading

In order to improve the environmental sustainability of concrete-filled FRP (fibre-reinforced plastic) tube (CFFT) column, a new kind of composite column, geopolymeric recycled aggregate concrete-filled FRP tube (GRACFFT) column, was proposed in this paper. The hysteretic behaviors of GRACFFT columns were experimentally investigated. The influences of different parameters, i.e., fiber types, section form, and reinforcement type were discussed. Based on the strain analysis, the plastic hinge length and utilization factor of FRP fibers for each GRACFFT column were also investigated. According to the experimental results, it was found that the proposed GRACFFT column showed favorable seismic performance with both high carrying capacity and deformation ability. The proposed GRACFFT column made with carbon FRP tube showed the best seismic behaviors in terms of yield displacement, peak load, ultimate displacement, and cumulative energy consumption. In terms of cross-section, the seismic behaviors of the circular GRACFFT column were better than that of the square column. Also, it was found that the substitution of steel reinforcements with steel tube could effectively increase the seismic behaviors of GRACFFT columns.