EXPERIMENTAL STUDY ON REHABILITATION OF SRC COLUMNS AFTER EXPOSURE TO FIRE

By tests on some SRC (steel reinforced concrete) columns strengthened with CFRP (Carbon Fiber Reinforced Polymer) and external steel clad after exposure to fire and some other comparable SRC columns without being strengthened after exposure to fire as well as at normal room temperature without exposure to fire, the rehabilitating effect of fire-damaged SRC columns are experimentally studied. Test results show that because of the confinement effect of CFRP and external steel clad, the failure process and distortion development of SRC columns after exposure to fire are more adequate when strengthened with CFRP and external steel clad, and the ductility of those columns are better than that without being strengthened. The load-bearing capacity of fire-damaged SRC columns can be enhanced to some extent, while the stiffness of SRC columns after exposure to fire can not be enhanced apparently when strengthened by CFRP. The stiffness of fire-damaged SRC columns with a relative large slenderness ratio can be enhanced in a certain extent when strengthened by external steel clad, but the stiffness rehabilitating effect of external steel clad on fire-exposed SRC columns with relative small slenderness ratios is not apparent. Compared with CFRP, the rehabilitating effect of external steel clad on load-bearing capacity of fire-damaged SRC columns is more remarkable. The ultimate strength of fire-damaged SRC columns can be fully restored when strengthened with external steel clad.