| Bridge engineering is important throat part in highways and railroads. It is critical to ensure its loading ability and normal function for smooth moving in a whole line. With the improvement of loading grade and extension of service year, the structural disease in bridge increases continuously. As a result, the loading capacity of bridge degrades gradually and the function of service deteriorates year by year. Therefore, it is urgent to study the reinforced technique in bridge structure, in order to improve the function of the bridge and to extend the service life of the bridge. Therefore, the study and engineering application of maintenance, reinforcement and repairing in bridge structure have been a wild concern in the world. This is a research task with important theories and realistic meaning.With its good physics and mechanics function, the carbon fiber reinforced plastics have been applied to the bridge reinforcement more and more. However, the study of concrete structure strengthened with CFRP-sheet is fixed primarily on the research of constant function in recently, the study of anti-fatigue performance of the concrete structure strengthened with CFRP-sheet has not been seen. According to the fatigue loading bridge subjected to enlargement more and more, the fatigue breakages of bridge have occurred continuously. Therefore, to study the fatigue performance of concrete beam strengthened with CFRP-sheet have the important theories and realistic meaning. To aim at this problem, in term to the feature of fatigue loading of bridge, This paper, on the base of analysis of current bridge reinforcement, makes a relative system experiment research and theory analysis for the fatigue performance of CFRP-strengthened concrete beam. According to the order of chapter of the thesis, this paper contains such research results as following:1. It is briefly introduced the purpose and meaning of the paper, expatiate the reason of fatigue collapse in bridge , discuss the present condition of improvement of fatigue performance of concrete beam with gluing steel plate and gluing CFRP , pointing out merit and shortcoming of two kinds method, the application of CFRP in bridge reinforcement is discussed. And this paper point out the main investigations of CFRP in the aspects of bridge reinforcement in thefuture. At the same time, it predicts the extensive application foreground.2. with the CFRP-sheet gluing the bottom of the reinforced concrete beam, its construction form and material have changed. So, the traditional reinforced concrete theories no longer applies obviously when calculating in curved design. On the foundation of analysis a quantity of experiments and theory home and abroad, the paper give a calculation formula for the cross-section anti-bending limit load capacity of reinforced concrete beam. At the same time, the paper discusses the establishment of fatigue load chart for the bridge structure and presents its calculation of stress chart. The calculation of bridge's fatigue strength under constant and variable loading is present in the paper. And the technical and contents of the structural fatigue test was expatiated.3. to evaluate and forecast the anti-fatigue effect of CFRP-strengthened concrete beams accurately and scientifically, this text proceeds the fatigue test of three intact beams, studying the fatigue performance of concrete intact beams strengthened with CFRP-sheet. to change the layer number of CFRP (one and two layer), the paper analyzed the anti-fatigue performance from the points of material stress, degree and crack of the beams. The research is that: after the same cyclic number of loading times, the steel stress of reinforced beams was much smaller than that of common beam; the deflection of reinforced beams was decreased by 40% - 50%, therefore, the anti-transformation of the reinforced beams is enhanced greatly. As a result, the fatigue life of intact reinforced beams increases by 60% - 80%.4. owing to many existing bridges to be reinforced exists different harm to some...
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