The Study On Cross-section Flexural Properties Of CFRP Reinforced Concrete Beams

The reinforced concrete has become one traditional and fully vital structural material which the modern engineering structure cannot lack. If the reinforced concrete structure exposes under corrosive environment for a long time, the durable question appears prominently. To the durability of reinforced concrete structure, engineering colleague have proposed many suggestions and conceives in the long-term practice and put them into practice, but the effect is still unconspicuous. At present to use the concrete structure with non-steel and textile fiber reinforced plastics bar (Fiber Reinforced polymer bar which is called FRP bar) is one way to solve durable question. Compared with steel bar, FRP bar has much superiority such as anti-corrosion, light weight and high strength, good construction performance as well as adapting to adverse circumstance condition and so on, and then approved gradually. It starts to apply in civil engineering by many forms.In this paper, bending properties of CFRP bar concrete beams, CFRP bars-steel composite concrete beams, CFRP bars-laminate of composite concrete beams are all studied, as well as compared with ordinary reinforced concrete beams. During the trial, we mainly obserce that the damage shape of beams impacted by reinforcement ratio change of CFRP bars, the impact of composite beams caused by the ratio change of CFRP bars and steel bars, and the impact of composite beams caused by CFRP bars and laminate paste layers'number change. Through the test, paper studies that beam's cracking load, the development of cracks, CFRP reinforcement, strain of CFRP laminate and the ultimate bearing capacity of beams, and analysizes the deformation performance of beams, and those verify the assumption of plane-section. Experiments show that, CFRP bar concrete beams, CFRP bars-steel composite concrete beams, CFRP bars-laminate composite concrete beams all conform to the plane-section assumption. According to test study, paper gives calculating methods of the ultimate bearing capacity of CFRP reinforced concrete beams, balanced reinforcement ratio and crack space. The results of theoretical calculation and experiment show that the calculation of the proposed method is feasible.To apply CFRP material in structural engineering, this article research has a theory and practical value to enhance the durability of the concrete structure.