ABSTRACT
An orthotropic steel deck system consists of a steel plate supported by longitudinal stiffeners and transversal crossbeams. Orthotropic bridge decks are prone to fatigue cracking due to the complicated weld details and the direct action of traffic loads. Although the stiffener-to-deck plate detail is of high importance in these decks, this connection seems to be one of the most difficult welding details since it can only be welded from the outside. Therefore, the influence of the weld penetration ratio and the geometry of the weld root on the stresses in the stiffener-to-deck plate connection is investigated. In Siemens NX, detailed 3D models based on real stiffener-to-deck plate connections were modelled. These 3D models were then included in a reference model of an orthotropic bridge deck, which consists of 2D shell elements. A parametric study was executed varying the weld penetration ratio of each model and investigating the peak principal stresses. The results clearly indicated that the shape of the weld root imperfection has a high influence on the peak principal stresses. The smaller and sharper the shape of the weld root imperfection, the higher the stress concentrations. The parametric study also showed that the absolute value of the peak principal stress decreases for an increasing weld penetration ratio. This is in contradiction with most conclusions in literature. However, most studies calculated a general model, of which the translations and rotations occurring in the zone of interest were then transferred to a smaller 3D model. This is an important difference with the method used in this study, which allows redistribution of the stresses since the 3D model is included in the reference model.
