An Experimental Evaluation on the Fire Resistance and Post-fire Structural Performance of Concrete Filled Steel Tube Columns

In this study, the test was conducted in two steps to evaluate the fire resistance performance and post-fire structural performance of the concrete-filled steel tube column (CFT column). As a first step, fire resistance tests were conducted on a CFT column with fire-resistant paint applied. As a second step, structural performance tests were conducted on the identical test specimens after 2–4 months of fire resistance test to evaluate the residual strength after the fire. As a result of the fire resistance test, it has been confirmed that almost the same fire resistance performance is secured even if the fire-resistant paint is applied with 60% of the thickness of the fire-resistant paint (2.7 mm), which has been recognized for its 2 h fire resistance performance. A post-fire structural performance test showed that the ratio of the maximum load versus the nominal compressive strength was 1.17 on average, and the strength reduction was about 10% compared to the test specimen without fire damage. Therefore, it is judged that the CFT column (D-Column), which has secured the fire resistance performance by applying the fire-resistant paint, will not significantly degrade the structural performance even after the fire.