Study Of Property Based On 500MPa Fine Grain Reinforced Concrete Beams Under Fatigue Loading

500MPa high strength hot rolled fine grain steel is a new generation of reinforced materials. Currently, the study of HRBF500 reinforced concrete structures is in its infancy, the study of its fatigue properties is still blank. Therefore, Combining with " The subject of high technology research and development (863) projects (2008 AA 030704)", the three rectangular cross-section and three T-shaped configuration HRBF500 reinforced concrete beams are designed and made. The fatigue performances of the beams are studied under the fatigue loads.First,500MPa high strength steel is tensioned test, the stress-strain curve is obtained. Then the there rectangular section beams and there T-beams are tested respectively under static loading. The reinforced strain, concrete strain and deflection of test beams are analysised under at all levels loading. Finally, the six beams amplitude fatigue load test are done, the fatigue performances are researched for test beams under cycles of fatigue loading for 1 to 250 million, including the steel and concrete strain, deflection and the development of cracks.The final result shows that the HRBF500 R.C beams poss better ability of anti-fatigue loads when the reinforcement ratio should be larger. According to the result of the experiment, when the reinforcement ratio of the HRBF500 R.C beams is more than 0.3%, and the maximum tensile stress of the beams is less than 150Mpa under the initial fatigue load, it can guarantee that the deflection and the maximum crack width meet the current code under the cycles of 250 million fatigue loading.Based on the result of the experiment, the formulas of the maximum stress in tension reinforcement and the deflection taking into the reinforcement ratio and the number of fatigue are proposed. The calculation results are in good agreement with the experiment results. They can be used in practical engineering to detect the maximum stress, and predict the deflection of beams under different number of fatigue, served for the design of engineering.