FATIGUE CRACK PROPAGATION AND STRENGTH OF WEB-GUSSET WELDED JOINTS UNDER VARIED PRINCIPAL STRESS DIRECTION

抄録

 The direction of the principal stress on web-gusset welded joint connected to a main girder web of steel girder bridges changes instantaneously so that the direction of shear stress reverses when a vehicle passes right above there. It is well known that the fatigue crack initiates and propagates in the direction perpendicular to the principal stress one, but fatigue crack propagation behavior and fatigue strength when the direction of principal stress changes have not been studied yet. In this study, to determine the propagation behavior and the fatigue strength in the stress field where the direction of the principal stress changes, fatigue tests on girder specimens and fatigue crack propagation analyses have been performed.