Experiment Investigation Of The External Per-stressed Reinforced Beams Stiffness And Crack-resistant

External Per-stressed Technique is one of the effective technique for reinforcing concrete beams. Lots of achievements of the application and research of reinforced measure have been acquired. However, there are lots of questions have not being solved. The checking computations for External Per-stressed beams'stiffness and rift have being used the formulary for computed unbounded Pre-stressed Concrete in concrete criterion. The effects of second-effect and beams'crack have been not sufficiently considered.The study was carried out to investigate the simply supported reinforced concrete beam short term stiffness and crack-resistant moment by external pre-stressing through experiment, and contrast the result of experiment with the result of formulary. Beside that, the thesis studied reinforcing concrete beams'crack-resistant capability under the condition of different control stress.The experimental research showed: Due to offset the difference in size and pre-stress effects of external load balance, reinforcement of in vitro using different methods were simple beam bending stiffness of different. Being Affected by secondary effect and the degree of cracking beam's Cracking cases, there was a big error between test Results and formula results. After the modified formula reinforced concrete beam stiffness closer to the short-term practical value. Moreover, the greater pressure on the effective prevention of tendon, it showed that Tendon used of reinforced concrete beam cracks in the beam had good control.