Temperature rise of cold-formed steel built-up back-to-back column under standard fire

Abstract

Cold-formed steel (CFS) has been used for various applications in building structure. Due to its many advantages, the uses of CFS can be widened to build new or to renovate existing single one or two families private homes. However, the fire resistance of the CFS is a critical issue whereby inclined to lose its vigour when it is exposed to fire, compared to hot-rolled steel member. This study takes the opportunity to investigate the application of this material as column members subjected to the standard fire. Four columns were tested. One column with a static load was tested under the ambient condition, while the three other columns were loaded at different degrees of utilisation under the standard ISO 834 fire conditions. The increases of temperature on the column surface were monitored using thermocouple Type K and the analyses of this thermocouple reading was taken to evaluate the mean temperature of the column. The temperature behaviours of back-to-back column for all degrees of utilisation showed that, the web was a lower temperature compared to the flange due to the greater thickness of the web. Meanwhile, the failure temperature of the CFS could reach up to 651.0 ºC for 30.0 % degree of utilisation with 8.0 minutes of resistant time.