Multi-hazard performance of novel ductile beam-column connections under fire and seismic loading

Connections play a critical role in governing the robustness of steel structures under extreme loading conditions. This study proposes three novel beam–column connection prototypes incorporating semi-elliptical ductile components to enhance structural performance under multi-hazard scenarios. Finite element models are developed in Abaqus to investigate the behaviour of the proposed connections throughout the full fire process, including heating and cooling, as well as under cyclic loading representative of seismic actions. Temperature-dependent material behaviour is incorporated using a user-defined subroutine. The results show that all three prototypes exhibit stable behaviour during fire, accommodating the transition from compression induced by thermal expansion to tension governed by catenary action. The ductile components enable controlled deformation and effective force redistribution. Under cyclic loading, stable hysteretic responses are observed, indicating reliable energy dissipation and ductility. Overall, the proposed connections provide an effective approach to improving both fire resistance and seismic performance, highlighting the importance of controlled deformability in enhancing structural resilience under multi-hazard conditions.