Fatigue performance of rib-to-deck double-side welded joints in orthotropic steel decks

Abstract

Fatigue cracking of rib-to-deck welded joints is the major fatigue problem of the orthotropic steel deck (OSD). It is important to evaluate the fatigue performance improvement of rib-to-deck double-side welded joints in an OSD when compared with single-side welded joints. In this study, the software ABAQUS and FRANC3D were used to set up a multiscale finite element model for segments of an OSD. Under vehicle load, the mode I stress intensity factor (SIF) of a fatigue crack at the rib-to-deck single-side and double-side welded details without or with the effect of welding residual stress was computed. The relationship between the mode I SIF of the fatigue crack and the key parameters was analyzed, including welded penetration, thickness of deck plate and the initial crack surface length and depth. The results showed that the welding residual stress can significantly influence the SIF values of the rib-to-deck welded joints in the OSD. The maximum SIF of the crack in the rib-to-deck double-side welded joints was 29.6% less than that of the single-side welded joints, which can effectively improve the fatigue performance of the rib-to-deck welded joints. The effect of the welded penetration rate on the fatigue performance of rib-to-deck double-side welded joints was only slight. By increasing the thickness of the deck, reducing the initial crack surface length and depth, the SIF of cracks in the rib-to-deck double-side welded joints can be significantly decreased, and this approach improves fatigue performance.