Abstract
This paper discusses the deformation and the strength of the thin walled open section beams under combined torsion and flexure. On the C-type channels, these mechanical properties are analysed. The chief conclusion of this pape is that the combined torsional and flexural normal stresses of the beams are very great and the maximum twisting deformations should be limited under 10°from the view point of the strength. And then, the authors suggest two effective methods which prevent the twisting deformation and the extreme increase of the normal stress. The one of the methods is the Tie-Bar method and the other is Cover-Plate method. Experimental results of these methods are explained and illustrated.
