Optimal Safety Level of Acceptable Fatigue Crack

Limit criterion of stability fatigue crack propagation on building structures is not defined. Procedure leading to brittle fracture is known theoretically. Its application to practical building structures is unused. The paper focuses on probabilistic assessment of acceptable fatigue crack and theoretical critical crack. Risk of damage proceeds load effect. Fatigue crack growth is related to traffic load effect, acceptable fatigue crack to probability of extreme probabilistic load effect.