Fire performance of axially ductile connections in composite construction

To enhance the robustness of steel-framed structures in fire, a novel, axially ductile connection has previously been proposed. In this paper its performance is investigated when it is used to connect composite beams to steel columns in composite steel-concrete construction. The ductile connection is designed to satisfy the ductility demands of the composite beam at elevated temperatures. A reinforcement component has been added to the bare-steel ductile connection model to establish a component-based model of the composite ductile connection. The connection model has been incorporated into the software Vulcan, and is validated against detailed Abaqus FE models using solid elements. Results show that the proposed component-based model can efficiently represent the behaviour of the connection given by the detailed Abaqus simulations. Parametric studies using Vulcan have been carried out, varying three parameters; the connection thickness, the semi-cylindrical section radius, and the density of longitudinal reinforcing bars. Finally, a 2-D Abaqus composite frame model has been created to investigate the influence of shear studs on the behaviour of the composite ductile connections under different stud spacings.