Headed Studs Close to the Concrete Surface-Fatigue Behaviour and Application

Headed studs arranged close to the concrete edge, especially loaded in direction to the free edge, show a lower static resistance and partly a different behaviour than studs further away from the concrete edge. Whereas the static resistance for both load directions and the fatigue strength for a loading parallel to the free edge are well investigated in earlier research works, there is no design rule for the fatigue strength for the load direction orthogonal to the free edge. Based on push-out tests this paper gives information about the fatigue strength for a loading orthogonal to the concrete edge subjected to the edge distance. Another focus is the residual static resistance after a cyclic preloading. An interesting development is the application of corrugated steel webs in composite girders. Omitting the steel flange and welding the headed studs close to the surface as shear connectors leads to a favourable application. Due to the corrugation there are tension stresses in the studs limiting the resistance on one hand, however, the corrugation itself acts as connector in the concrete increasing thus the overall connection strength on the other hand.