EXPERIMENTAL STUDY ON STRESS-STRAIN RELATIONSHIP OF CFRP-CONFINED CONCRETE PRISM AFTER FIRE

The stress-strain relationship model of concrete prism confined by CFRP after fire is scarce, which gives great trouble after fire to the study of mechanical properties of compressed concrete member strengthened by CFRP. Based on some influencing factors, stress-strain relationship of concrete prism confined by CFRP after fire is analysed. Experimental results indicate that strength of concrete prism after fire have a large certain extent increase as the result of the action of CFRP. Fabric breadth has a little influence to its characteristic parameters and stress-strain curve, when the greatest temperature, fillet radius and quantity of CFRP don’t change. Temperatures, quantity of CFRP and fillet radius have different extent influence to its characteristic parameters. Based on the experimental results, the stress-strain relationship model of the concrete prism confined by CFRP after fire has been proposed, which is nearly consistent with experimental curves and has better precision. This has established a reliable foundation for the accurate calculation of concrete structures strengthened by CFRP after fire.