Experimental Research On Static And Fatigue Mechanical Behavior Of Corroded R.C. Beams

With a broader range of applications of RC structures in the world, structural durability issues become increasingly prominent, steel bars corrosion of RC structures is one of the important factors leading to lower durability. In reality, there are a lot of corrosion of reinforced concrete structures under cyclic loading, but the mechanical performance is not on the issue, this article through electrochemistry fast corrosion method, on the basis of experimental study at static capacity performance of corroded RC beams, launched the fatigue properties experimental study of corroded RC beams. In addition, in view of the outstanding strength behavior that the steel fiber demonstrates in the construction work is employed, this article has also carried on static and fatigue test studies at corroded reinforced steel fiber concrete beams, to explore the steel fiber's effects under static and cyclic load .Through the static load test for 10 RC beams, The research has analyzed the influences of the test beam capacity, load - deflection curve, reinforced bars and concrete's strains and so on with the steel bar corrosion rate and the quantity of steel fiber. The test result indicated: With the steel corrosion rate increases, bearing capacity and stiffness of the tested beams reduce obviously, the tensile ratio increases, the inter-average strains of steel bars and concrete no longer meet the section assumption. owing to the strength and crack resistance of steel fiber, the performance of corroded reinforced steel fiber concrete beams is superior to the performance of corroded RC beams, the average strains of steel bars and concrete meet the section assumption basically.Through the fatigue tests for 8 RC beam, the paper analyzes the change relation of the fatigue strength and fatigue life, the stiffness characteristics, the deformation of the test beam with the steel bar corrosion rate, the quantity of steel fiber and the fatigue load stress level.The results show that: As the steel corrosion rate and the fatigue load stress level raises, the fatigue strength and fatigue life of the test beam obviously drops; the stiffness have gone through a substantial increase, a sharp decline and steady development three stages with the increase in the number cyclic load. Mixes in the steel textile fiber is possible to offset the injury damage which the steel bar corrosion causes, and to effectively improve the fatigue performance of corroded RC beams.Finally, this article has analyzed the influence mechanism of steel bar corrosion and the steel fiber to mechanical performance. Simultaneity, the simplified computation model for static capacity and the design method of fatigue strength and calculation methods of fatigue stiffness of corroded RC beams are proposed.