STUDY ON FINITE OUT-OF-PLATE DEFORMATION OF RECTANGULAR PLATES SUBJECTED TO COMPRESSION AND IN-PLANE BENDING.

When a thin-walled plate girder is subjected to repeated bending, there are possibilities of the initiation of fatigue cracks along the upper boundary of the web. They are caused by secondary bending stresses produced by out-of-plane movements of the web under the repeated in-plane bending, due to its unavoidable initial deflections. Not only magnitude of the initial deflections, but also their shape will influence greatly an increase in the secondary bending stress and then the initiation of the fatigue cracks.