Temperature field characteristics of cylindrical aluminum alloy reticulated roof system under localized fire

Abstract

Aluminum alloy shells are increasingly used in public buildings as a supporting structure for roofing enclosure construction in large spaces. In performance-based fire protection design, an empirical design criterion of 150 °C and relevant empirical formulas are used; however, the safety margin and prediction effect are not verified through full-scale experiments, and therefore, the effect of the roof system on the near-roof temperature field in practical engineering is yet to be investigated. In this study, a simulated fire experiment was conducted using a cylindrical aluminum alloy reticulated roof system model. The heat release rate of this restricted fuel fire source during the stable burning stage reached 8.1 MW. Fire Dynamics Simulator (FDS) was used to reproduce experimental results, and the numerical model of the shell member was simplified; further, existing empirical formulas of scholars such as Li were compared. The results indicated that although 150 °C is a large safety margin, it may limit architectural function. The simplified shell model provides an effect-equivalent approach for building thin-walled members in FDS. The shell is the main factor that delays the time required for the near-roof space to reach thermal equilibrium. The existing empirical formulas cannot be used for the studied roof system directly, and they may be improved through coefficient adjustment and other such methods.