Cracks occurred in the main weld joining the web and upper wing panel of an overhead crane girder of I-section, some of which have expanded to the structure material and even led to girder fracture.

Main girder and other components of overhead traveling crane are typical welded structures, the primary failure type of which is fatigue crack.

In recent years some new profile steels are used for main girder of domestic made electric single girder overhead travelling crane.