Seismic Performance of Square Reinforced Concrete Columns Strengthened with Hybrid FRP

In order to research the feasibility of structural seismic retrofit with Hybrid FRP(HFRP) ,seven square reinforced concrete columns are tested under low cyclic alternate load to investigate the performances such as seismic behaviors,failure mode,hysteresis curves,skeleton curves,ductility,degradation of stiffness and energy consumption of square columns strengthened with HFRP. The effects of the axial load ratio,the amount of HFRP and the stirrup ratio on the seismic performance of square columns strengthened with HFRP are studied. The results show that the seismic performance can be improved effectively for square columns strengthened with HFRP. The effect of axial load ratio is great,and HFRP can confine concrete more effectively when the axial load ratio is low. The higher the axial load ratio is,the lower the confinement and the ductility are. The results also indicate that increasing the amount of HFRP can improve the seismic performance effectively when the axial load ratio is low but barely have any effect when the axial load ratio is high. The seismic performance of the square columns can be improved significantly by increasing the stirrup ratio.