Performance of Headed Stud on Steel-concrete Composite Bridge Deck as Shear Connector Subjected to Normal Force

Abstract

The objective of this study was to determine the influence of normal force acting on a steel-concrete composite bridge deck on both the shear stiffness of the headed stud welded on the bottom plate of composite deck and the damage process of the deck. The study also attempted to consider the current design method of headed studs for a composite bridge deck. First, the relationship between shear the force and displacement was obtained from the FE analysis using a model that assumes a part of a bridge deck was exposed to eleven different normal force conditions. Five of these conditions were the compressive, the other five were tensile and the last was without any normal force. The highest shear stiffness was obtained under the normal compressive force condition being equivalent to 50% of the compressive strength of the concrete among the eleven cases. The stress distributions of the bottom steel plate with the normal forces were different from that without any normal force. Furthermore, the restraint conditions of the bottom steel plate were examined in a sensitivity analysis. The analysis concluded that the restraint conditions of the bottom steel plate influence the interlock between the concrete and the headed studs. Full scale model simulating the composite bridge deck in service was built in order to focus on the differences of the carried load by each stud depending on their location on the deck. Static analysis using the full scale model clarified that the stress distribution of the studs itself and the damage state of their surrounding concrete were dependent on their location. Coefficient for the design equation of the headed studs as shear connectors of steel-concrete composite bridge decks was proposed with a consideration of the influence of normal forces and location of each stud.