The Influence of Reinforced Concrete Beams Crack on Size Effect

We research the influence of reinforced concrete beams crack on size effect by using the fracture Mechanics analysis method and Fracture toughness. First, the weight of three spot curved beam,the load,the steel bar, and the cohesive strength of breaking-down process area were superimposed of the stress intensity factor which has in the crack tip, in order to examine whether it has surpassed the fracture toughness, and judge the crack whether will be to expand. Then we went to iterative computation through increasing the load and the crack length which obtained the carrying capacity of corresponding size component, we used the Mat lab programming in the entire computational process. The result shows that although the steel bar limited crack expansion of concretes beams and caused "the plasticity" characteristic, the reinforced concrete beams had the size effect phenomenon still, it did not obvious compare with the plain concrete.