Simplified theoretical model on fire performance of load bearing cold-formed steel wall systems

In recent years, cold-formed steel (CFS) wall systems have been increasingly utilized as load-bearing structural components in low and mid-rise buildings. The fire performance of such wall systems has become an important concern in fire safety design. A theoretical investigation on the simplified model of load-bearing CFS wall systems under fire conditions was carried out. An implicit thermal response model which considers the influence of thermal physical properties and fall-off of different boards was developed to predict the heat transfer across the cross section of CFS wall systems. In addition, a thermo-mechanical response model was presented to predict the time-dependent lateral deflection, failure mode and fire resistance time for CFS wall systems in fire. Both the thermal response model and thermo-mechanical response model were validated by previous fire experimental results of load-bearing CFS wall systems. Based on those simplified models, the fire performance of different CFS wall systems was simulated. Both the configuration details and corresponding load levels were given for CFS wall systems with the fire resistant rating of 30 and 60 min. Hence, the practical fire resistant design of such wall systems was developed and should meet the fire resistant requirement of low-rise buildings in China. ©, 2015, Science Press. All right reserved.