Abstract: Bending stress in the web of a steel crane girder subjected to a concentrated torue is an important factor influencing the strength of the web. It was shown that 1,2,3 the flexural rigidities of the rail and the transverse stiffeners, which have not been accounted for in the previous analyses, can give a considerable effect on this stress, Considering these factors, this paper studies the calculation method of this stress by the harmonic analysis and dirives a simplified formula for engineering design. The calculated results are compared with the knowm expenmental results of numerous tested beams.