The temperature of the steel tube of a CFT column rises rapidly upon a fire causing the deterioration of its strength, while the concrete inside of the tube having large heat capacity provides fire-resistance performance. In order to employ CFT columns as fire-resistant structure, it is necessary to conduct studies on the factors exerting influence on structural capacities and the influence associated with each condition. Concrete’s compressive strength, cross-sectional size, axial load ratio and boundary condition are the major factors which are influential in fire-resistance performance. In particular, boundary condition between columns and beams is one of the major factors which decide fire-resistance performance because it exerts influence on load carrying capacity. The result of the test conducted in this study showed that fire-resistance time of 106 minutes was secured in the specimens with clamped ends and that of 89 minutes in those with pinned ends when cross-sectional size was 360 by 360. In the specimens with cross-sectional size of 280 x 280, fire-resistance time of 113 minutes was secured under the condition of clamped ends and that of 78 minutes was secured under the condition of pinned ends.
Research Regarding Analysis of the Target Safety Standard for Fire Resistance Design and its Mode of Expression - Estimation for the Safety Standard Targeted by the Verification Method for Fire Resistance Performance - Chapter 6 Variations of the Design Fire Source and Fire Behavior of Fully-Developed Fires
