Hybrid fire collapse simulation of reinforced concrete structures under localized fires

The safety of extensive reinforced concrete (RC) buildings under sudden fire scenarios is of particular concern nowadays. Localized fires may bring serious damage and even collapse to the RC bearing structures, causing huge casualties and economic losses. However, due to the limitations of test facilities, technology, and high costs, etc., full-scale and even reduced-scale structural fire tests have been very limited. The recent development of numerical techniques instead of challenging physical tests has provided exciting prospects for refinement of structural fire behavior prediction. This paper is therefore focused on a hybrid fire collapse simulation method through performing damage analysis of the locally fire-heated components and collapse simulation of the remaining major structure. The damage and failure behavior of the fire-exposed substructure is simulated based on an energy-based elastoplastic damage model for concrete at elevated temperatures. While the resulting deformation and collapse of the rest main structure is modeled by conventional collapse analysis. The key to the hybrid simulation is the coordination of internal forces and deformations between the substructure and the main structure. The developed method allows for an integrated simulation of the whole process from high temperature damage of materials to fire destruction of local components and to the collapse of the entire RC structure.