Dual-3D hybrid fire simulation for modelling steel structures in fire with column failure

In order to capture global load redistribution in a structural system subjected to fire and fire induced local failure such as column buckling, this paper develops a dual-3D hybrid simulation scheme with multiple sub-structure models and a 3D structural system model to investigate structural fire responses. This hybrid simulation scheme is implemented with simulation models in OpenSees for fire and the naturally compatible middleware OpenFresco. A model of the Cardington plane-frame test was built and used to validate the presented approach regarding the performance of traditional thermo-mechanical model and test results. The modelling results demonstrate the necessity of modelling central columns in detailed models for local failure and the importance of including floor slabs in the structural system model. The effect of larger fire furnace area and the unprotected length of columns are studied using the dual-3D hybrid models, which warns the risk of floor failure following the column bucking and squashing. More importantly, the work in this paper paves the way for hybrid testing of structures in fire equipped with a 3D structural system model synchronized with multiple substructure models and in-laboratory tested specimen.