NUMERICAL SIMULATION ON FIRE RESISTANCE OF COMPOSITE FRAME WITH CFST COLUMNS BASED ON MULTI-SCALE METHOD

The composite frames with concrete-filled steel tubular (CFST) columns may damage in a progressive collapse mode because of the failure of the CFST columns under local fire attack. This paper presents a finite element model (FEM) of a three-story-three-span planar composite frame with CFST columns exposured to local fire scenes based on a multi-scale method using ABAQUS. The reasonable thermal and material models of steel and concrete were considered, respectively. The element models and the interactions of the beams and columns were simulated logically in the FEM. The structural deformations, internal force distributions and the failure modes of the composite frame were studied under four different fire scenes and the fire resistance rating of the frame were calculated. The results show that the fire resistance rating is the most maximum when the fire scene located at the middle floor due to the effective constraint by the other members.