Behaviour of Slip-Critical Shear Connectors Between Multi-void Extruded Aluminium Bridge Decks and Steel Girders

The use of aluminium alloys for bridge decks has gained significant interest in recent years due to the material’s high strength-to-weight ratio, durability (i.e. high resistance to atmospheric corrosion), and low maintenance requirements compared to the traditional deck material such as reinforced concrete. Moreover, the material’s extrudability property provides designers with the ability to optimize sections by placing the material in areas that maximize structural properties and joinability. For roadway bridge applications, one of the most practical and cost-effective solutions consists of aluminium deck panels, made from welded multi-void extrusions and supported on steel I-girders. In the traditional deck-on-girder bridge design, it is desirable to develop a slip-resistant connection between the bridge deck and the supporting girders to avoid unexpected instability due to fatigue or vibrations. Developing a slip-resistant joint between hollow aluminium deck panels and steel I-girders presents unique challenges, including a lack of access to the interior of the deck panel for the installation of pretensioned bolts and the behaviour of dissimilar metals under mechanical and thermal loads. In the present study, the suitability of a commercial blind bolt type was examined by testing a steel–aluminium plate assembly to evaluate the slip and relaxation characteristics of the joint at ambient temperature. Results of the study indicate that the use of the selected blind bolt is suitable for a slip-resistant aluminium–steel joint. The rapid initial joint relaxation can be reduced significantly by retightening the bolts, 24 h after initial installation.