Behavior of fin-plate connection of a composite beam subjected to different fire scenarios

The behavior of fin-plate connections of a composite beam exposed to different fire scenarios was numerically studied by experimentally validated models. At elevated temperatures, the closure of the gap between the beam end and column was observed to transform a hinge connection to a moment connection, reducing the beam deflection. In fire, a slow cooling of the beam close to the connection is a favourable approach to affect the responses of the beam and the fin-plate connection. Under heating and cooling cycles, the axial forces developed in the beam fluctuated between compression and tension. At the end of the first cooling phase, the shear plate was found to be a critical member in which the further development of the axial tension force can fracture the fin-plate connection at the end of the second cooling phase.