Progressive collapse resistance of precast RC beam-column substructures with dry joints under fire condition

For better understanding of the collapse resistance of dry-connected precast reinforced concrete (RC) structures under fire-induced column-removal scenarios, three dimensional detailed thermal-mechanical coupled numerical models are built to investigate the load capacities and failure modes of precast RC substructures under ISO-834 fire. Python scripts are used in this study to automate the model development and facilitate the model calibration. The effect of fire-induced thermal expansion and material degradation in the stress analysis models are realized through the adoption of temperature-dependent material definition with both the elongation and stiffness reduction being considered. The temperature information is introduced through pre-defined field function of ABAQUS which allows inputs of previously generated heat transfer output database. A systematic parametric study is also performed to analyze the effect of structural design features on the load capacity and failure modes of column-removed precast substructures under fire scenarios. Joint enhancing parameters, such as angle thickness and angle rib thickness, prove to be more efficient in limiting the structural deformation rather than component-enhancing ones like concrete strength and reinforcement ratios under identical working condition. Failure modes are sensitive to concrete strength under penultimate column removal scenarios where edge column buckling is observed under fire scenarios. Span-to-depth ratio can effectively change the in-plane stiffness and thus affect both the structural resistance and failure modes.