Experimental Study On Flexural Strengthening Technology Of Prestressed Carbon Fiber Plate

Now, the frequently-used reinforcement method of carbon fiber materials is pasting carbon fiber plates or carbon fiber sheets at the tension zone of constructions. This method can not make the most use of high-strength properties of carbon fiber materials.By applying prestress ahead to the carbon fiber materials, the intensity utilization of carbon fiber materials can be greatly improved. Adopting prestressed carbon fiber plate bending strengthening existing railway bridge can significantly improve the anti cracking performance of beam body and achieve good reinforcement effect.This paper took the carbon fiber composite plate materials as the research object.The static,fatigue,relaxation,high and low temperature test researchs of carbon fiber plate combined with anchorage clamp device were conducted. Test results show: the static breaking strength of carbon fiber materials was more than 2800 MPa,above the design value 2600 MPa.The static strength reduced by 7% after 6 million circulating load. After 1000 hours, the relaxation ratio of carbon fiber materials was less than 2%. The static strength of carbon fiber material in the low temperature environment of-40℃ is basically unchanged. The static strength reduction of 9.1% at the high temperature at 80℃. Carbon fiber plate has excellent mechanical properties. Using externally prestressed carbon fiber plate to strengthen the railway ordinary high 32 m prestressed concrete T beam. Theoretical calculation and static load test were carried out before and after. Test results show: Compared with the original beam, the decompression flexural moment of cross section of beam increased by 15.6% after the reinforcement, close to the theoretical value 14.8%. The antibending strengthening effect is notable. The strengthening design target realized.