ANALYTICAL BEHAVIOUR OF CONCRETE FILLED STEEL TUBULAR COLUMN-REINFORCED CONCRETE BEAM PLANAR FRAMES SUBJECTED TO FIRE

This paper develops a finite element analysis (FEA) model for concrete filled steel tubular column - reinforced concrete beam planar frames under coupled loading and fire with heating and cooling phase. The modeling is validated against existing test data. Based on the FEA model, the mechanical behavior of the composite frame under ISO-834 standard heating and cooling fire is analyzed, and the influences of beam load ratio, column load ratio, and heating time ratio are investigated. The results indicate that the composite frame will fail in both the heating and cooling phases. Whether or not the composite frame reaches its failure in cooling phase is related to beam load ratio, column load ratio, and heating time ratio.