Effect of Pre-overload on Fatigue Life Extension of U-rib Steel Floor Slab Root

Fatigue damage has been recognized as one of the critical issues in the design of welded structures. Among different welded joints, one-sided welding of fillet joints is a common practice that has the advantages of an excellent workability and to reduce the manufacturing costs. However, it is characterized by the presence of weld roots. The same type of welding is often used for U-rib steel components, where, in many cases, fatigue cracks are initiated from the weld root. Subsequently, the cracks often propagate and penetrate the upper deck or the weld bead. These cracks, originated from weld root, are not easy to be detected even by using novel non-destructive inspection techniques. A novel method to improve the fatigue performance of the weld root of U-rib has been developed by the co-authors of this work. The new strategy consists in introducing a compressive residual stress field by applying a tensile pre-overload from inside of the U-rib structure. The effect of the pre-overload o...