FIRE RESISTANT BEHAVIOR OF CONCRETE-FILLED STEEL TUBULAR COLUMNS WITH SQUARE CROSS-SECTIONS UNDER THREE-SIDE FIRE

摘要

A FE model was developed employing ANSYS to analyze the cross-sectional temperature distributions and mechanical behavior of the concrete-filled steel tubular (CFST) columns with square cross-sections under three-side fire. The predicted results were in good agreement with the test ones. Furthermore, comparisons were made between the CFST columns heated on three sides and four sides. It is found the cross-sectional temperature distributions in the former case are single axial symmetry due to the non-uniform heating conditions, while those in the latter case are axial symmetry, and additional strength eccentricities are thereby formed and acted on the columns combining with the load eccentricities. Based on the FE model, a developed fire resistant behavior analysis was undertaken, in which the fire action conditions and load eccentricities were mainly taken into account. The work done in this paper provided references for researching of the CFST columns under three-side fire.