Finite Element Analysis of Reinforced Concrete Deep Beams under Fatigue Loading

This paper presents a two-dimensional damage constitutive model for reinforced concrete structures under fatigue loading. The two-dimensional strength envelope of concrete under fatigue loading is established, combining the experimental results of the uniaxial strength degradation with load repetitions and the ratio of the two-dimensional strengths to the uniaxial strengths under static loading. Deformational behavior with load repetitions is considered by the concept of damage accumulation for concrete in the framework of continuum damage mechanics. Once the stress state reaches the fatigue tensile strength, a crack is assumed to form. Strength degradation of reinforcing steel with load repetition is also considered. When the fatigue strength of reinforcing steel is reached, brittle failure is assumed. The reinforcing bar and the surrounding concrete is simulated as perfectly bonded. Numerical analysis of concrete deep beams with various web reinforcements under fatigue loading is then carried out by using the present constitutive model. The results show that the proposed material model is reasonably accurate.