Experimental Reserarch On The Flexural Behavier Of RC Beams Strengthened By Aramid Fiber Reinforced Polymer Under Quadratic Loading

The concrete structure is in the civil engineering applies the most widespread structure. Because the material gets older, the environment corrodes, use question and so on function change, construction quality as well as natural disaster causes the massive structures facility to need to repair and the reinforcement. The textile fiber reinforced plastics (FRP) is at present constructs the structure reinforcement project domain one kind of new material, has inoxidizability which the steel products is unable to compare and processing. Looked from the present research present situation that, domestic most concentrates in the carbon fiber and in the glass fiber reinforcement concrete component research, (AFRP) reinforces the concrete component to the fragrant black silk ribbon textile fiber the research to be less. Compare with the carbon fiber and the glass fiber, the fragrant blacksilk ribbon textile fiber has high anti- pulls with the anti- impact intensity, also the soft easy bend, not to be able to have the shield and so on many merits, in the bridge, the tunnel, the house is ostructuralism earthquake resistance reinforcement makes up the strong aspect to have the application prospect which the carbon fiber and the glass fiber can not be substituted.Based on the flexural behavior of 13 beams strengthened with FRP under quadratic loading,the influence on strengthening effect is analyzed with the parameters such as FRP layers,FRP kind,steel percentage,preload,unload.The results indicate that the bearing capacity of the specimen increased remarkably when strengthened with longitudinal FRP, reinforced beam's supporting capacity to increase along with the textile fiber cloth layer increase, but the supporting capacity enhances the degree not to assume the linear relations to the reinforcement layer; When glues the same layer the fragrant black silk ribbon textile fiber cloth, is reinforcedthe component steel percentage lowly, uses the effect which the fragrant black silk ribbon textile fiber cloth reinforces to be moreobvious; The choice glass fiber and the fragrant black silk ribbon textile fiber combination reinforcement achieves the economical as far as possible the rationality; The lag strain size is decided two times of stress structures reinforcement effect key aspect, textile fibercloth lag strain bigger, is smaller to the supporting capacity enhancement, the test result indicated: The pre- increase regulation goes past in a big way, the lag strain is bigger; In order to reduce the lag strain, before the reinforcement should carry on the unloading as far as possible to the structure, only must unload to about original structure limit supporting capacity 40% can obtain the good effect.Finally, based on the test results, inferred the fragrant black silk ribbon textile fiber cloth to reinforce the reinforced concrete beam's right section anti-curved supporting capacity formula, the fragrant black silk ribbon textile fiber cloth reinforces the reinforced concrete beam's short-term rigidity as well as is bent the ductility simplification formula. Uses the above formula and the actual value contrast error is smaller, it may supply the actual reinforcement engineering when design refers.