Flexural Capacity Of Overloading Damaged RC Τ-Beams Subject Under Dry-Wet Cycles

Using fiber-reinforced plastic (FRP) to strengthen or retrofit existing reinforced concrete members has become more and more popular in the last couple of decades. Carbon fiber-reinforced polymer (CFRP) materials have higher stiffness and enhanced durability characteristics compared to other composites and have been frequently used for applications in concrete structures. Many reinforced concrete bridges are in service with cracks, so strengthening of this kind of bridge is urgently needed. But due to the versatile applications of concrete in different construction fields, CFRP reinforced concrete structures may often be exposed under Dry-Wet cycles, wetting and drying cycles, freezing and thawing conditions, and many other severe environments. So precracked reinforced concrete structures strengthened with CFRP under Dry-Wet cycles can simulate the structures strengthened with CFRP in practical project, which can be used for studying the strengthening structures durability decrease mechanism and providing information to the design of structures strengthened with CFRP.Fifteen reinforced concrete beams were made in this experiment, and experimental investigation of the bending capabilities were carried out. The influence of overload damage and the Dry-Wet cycles were investigated in this paper. Many conclusions have been obtained from experimental study.In the paper the beams after overload damage were tested to study the bending capacity of RC T-beams. The specimen ultimate flexural capacity, ultimate deflection and rebar strain of overload damage were analyzed. Simulated overload damage to the bridge. The results show that the RC T-beams after overload damage have some residual deformation and cracks, the damage concrete can’t decreased the bending capacity of RC T-beam, but as a result of the steel bar in test beam after repeated stress will produce a certain effect of cold-drawing, the strength of RC T-beams after overloading damage increased slightly. And the ductility have been improved.In the paper the beams after overload damage were tested to study the bending capacity of CFRP strengthened RC T-beams. The results of the experimental indicate that significant strengthening on the ultimate load and rigidity of reinforced concrete beams can be realized by bonding CFRP sheets to the beams, restraining of the crack are improved. The function of overload damage will reduce the reinforcement effect of CFRP, improve the utilization rate of CFRP and little influence on the ductility of the RC T-beams after reinforcement.In the paper the beams after the Dry-Wet cycles test were tested to study the bending capacity of CFRP strengthened RC T-beams. The bonding ability between CFRP and concrete interface is weakened under Dry-Wet cycles. The function of the Dry-Wet cycles test will reduce the ultimate flexural capacity and little influence on the ductility.