Chapter 4: Fatigue

Fatigue is one the most relevant cause of failure of infrastructures or part of them, like bridges, cranes and machinery, offshore structures and so on. A lot of existing structures, mainly built before the 1980, have been designed using inappropriate fatigue classification of details or underestimating the aggressiveness of actual load spectra, so that they are subject to high fatigue failure risk, as demonstrated by fatigue cracks detected even recently in several structures. Fatigue assessment and evaluation of residual fatigue life is then a key topic in verification of existing infrastructure, also in view of designing repair interventions of fatigue damaged details and planning of future maintenance and inspection programmes.