Fracture mechanics based fatigue life estimation of crane welded box girder

The fatigue destruction caused by random load is one of the main destruction forms of the crane welded box girder.The values of the various fatigue parameters of welded box girders on overhead and gantry are summarized in this paper on the basis of previous test data and research achievements.The equivalent processing for random load is performed with RMS method and a way to estimate the fatigue crack extension of the welded box girders is proposed based on calculating formulas for constant amplitude loading fatigue crack during stable extending period and the property of the random loads exerted on the cranes.