Experimental research on the fire performance of a special cross-shaped composite column with a high-strength concrete-filled steel tubular core

Abstract

To improve the mechanical performance of specially shaped reinforced concrete columns, which are widely applied in China, an innovative specially shaped composite column with high-strength concrete-filled steel tubular core was developed. To investigate the fire performance of this specially shaped composite column, two series of fire tests, including the fire resistance test series and the post-fire test series, were conducted on five full-scale specimens. The test parameters include the axial load level, the spacing of stirrups, and the fire exposure time. Compared to the test result of a controlled specimen that was axially compressed to fail without exposure to any fire, both the fire resistance under fire and the residual capacity after fire of this specially shaped composite column were analyzed and studied. The results indicated that the inner concrete-filled steel tubular core plays an important role in both the fire resistance and the post-fire performance, and that the post-fire residual capacities of three post-fire testing specimens were also largely increased.