Performance of concrete-filled steel tubular column-wall structure subjected to ISO-834 standard fire: Experimental study and FEA modelling

This paper reports a full-scale fire testing of concrete filled thin-walled steel tubular (CFST) column-wall structure. All together eight specimens were designed and tested under axial compression load and subjected to ISO-834 standard fire. Load ratio, fire-exposure time and insulation scenarios were varied in the testing program. Cement mortar, aerated concrete block, and mineral wool were used as the insulation layer materials. Test results including temperature to time relations, axial deformation, and fire resistance as well as failure modes were described. A finite element analysis (FEA) model was established in order to simulate the thermal and structural behavior of CFST column-wall under fire. The FEA model was verified against test data and turned out to be reasonably accurate in predicting the temperature distribution, axial displacement, fire resistance and failure modes of CFST column-walls. Sensitivity studies were carried out to determine some major parameters in the FEA model. Discussion was made on the influence of thermal resistance, spalling of the insulation layer and confinement of inner concrete on the modelling of CFST column-wall structures.