Modelling of composite fin-plate connections under fire conditions using component-based method

Composite floor systems with fin-plate connections are widely used in multi-storey buildings, but there is currently no reported research on the development of a component-based model of a fin-plate connection at the beam-column interface that includes the effect of slab continuity above the fin-plate connection. In this research, a component-based model is developed to simulate a composite fin-plate connection. The component-based composite fin-plate connection model is able to simulate the slab continuity when installed at the beam-to-column interface of a composite floor system model. Fracture criteria for the plates and bolts of the fin-plate connection are adopted in the model to simulate connection failure. The component-based composite fin-plate connection model has been implemented in the software Vulcan, and is validated against a range of existing results, covering tests of individual fin-plate connections at ambient and constant high temperatures, subjected to combinations of tensile force, shear force and moment. The element is also used to simulate a test in which fin-plate connections were implemented at both ends of a composite beam with slab continuity, and subjected to elevated temperatures. The Vulcan modelling results show good comparison with the test results. The proposed component-based composite fin-plate connection model is shown to be a reliable tool to enable the performance-based finite element modelling of full-scale composite beams with fin-plate connections under fire conditions. Subsequently, parametric studies are carried out to investigate the influence of the key parameters, axial restraint stiffness and reinforcement ratio, on the behaviour of the composite beam and the connection force distribution, as well as to compare the very dissimilar structural responses of bare-steel and composite beams with the same geometries and loading conditions in fire.