A Component-Based Model for Fin-Plate Connections in Fire

A component-based model for fin-plate connections has been developed to study the robustness of simple beam-to-column connections at elevated temperatures. The key aspect of this component method is the characterisation of the force-displacement properties of each active component at any temperature, represented by a non-linear "spring". The prescribed temperature-dependent characteristics of any given bolt row are governed by the failure mechanism of the weakest component, based on experimental and analytical findings. A major additional complication involves force reversal in components, which may occur because of temperature change, without any physical reversal of displacement. The Masing Rule has been adapted to incorporate this effect for particular force directions. To account for the bolt slip phases, force transitions between tension and compression take place only when positive contact between a bolt and the edge of its bolt hole is re-established. The results of high-temperature tests on connections have been used to substantiate the developed component model. The component-based connection model has also been used to study joint behaviour in structural sub-frame analyses. This approach will enable more valid performance-based assessment of the overall responses of connections, including their robustness, in design fire scenarios.