Experimental study on the seismic behavior of CFRP-strengthened seismic-damaged recycled aggregate concrete-filled rectangular steel tube frame columns

The seismic performance of rectangular steel tube steel tube frame columns filled with recycled aggregated concrete and reinforced with carbon fiber cloth was evaluated. Four frame columns were designed and fabricated at a scale of 1:2, seismic damage was simulated, and low-cycle reciprocating load tests were conducted. The results showed that the damage process and damage pattern of the specimens were similar to those of concrete-filled steel pipe frame columns. The hysteresis curve of the reinforced specimens was fuller than that of the unreinforced specimen, and the shape of the hysteresis curve changed from a shuttle to a bow shape; The carbon fiber cloth improved the specimen's bearing capacity and stiffness, significantly improved the ductility, energy dissipation capacity and seismic performance. The reinforcement effect of the carbon fiber cloth was related to the pre-damage level of the specimens, and used of carbon fiber cloth improved the seismic performance of the specimens. The hysteresis curve and skeleton curve obtained from the test were used to establish the restoring force model of the specimens, and the displacement amplitude of the bearing capacity obtained from the model and experiment were compared. The restoring force model can be used for the elastic-plastic seismic analysis of the seismically damaged rectangular steel tube frames filled with recycled aggregate concrete.