Fatigue life of structural concrete
In this chapter, path-dependent fatigue constitutive models for cracked concrete tension and shear transfer are proposed and directly integrated with respect to time and deformational paths actualized in structural concrete. The authors aim to verify the multi-scale modeling to be consistent with the fatigue life of materials and structural members under high repetition of forces. The mechanistic background of the extended truss model for fatigue design is also investigated. The coupling of fatigue loads with initial defects is simulated and its applicability is discussed. As well, analytical scrutiny is made of the shear fatigue behavior of reinforced concrete (RC) beams subjected to moving loads, and the mechanism for dramatically reduced fatigue life under moving loads is computationally discussed. A simplifi ed relation for the prediction of fatigue life under moving loads is proposed for practical use. The effect of randomness in the position of loading is examined and its implication for the reliability of the current fatigue life assessment method is put forward.