Abstract
Bi-axial stress usually exists in welded joint between main girder web and lateral girder flange. For the purpose of examining influence of hi-axial loading on the fatigue strength, a test set-up has been developed to conduct fatigue tests under hi-axial loading. Fatigue tests have been carried out under the condition that stress range on the web was set at 100N/mm2 and stress range on the flange was 0, 50, 100 or 150/mm2. The fatigue life under bi-axial loading was drastically decreasing compared with the fatigue life under single axial loading. This fact was derived from stress increment due to bi-axial sress and stress bi-axiality itself, which was confirmed by stress measurement tests and stress analyses.
