Fire fragility of reinforced concrete panels under transverse out-of-plane and compressive in-plane loads

Abstract This article focuses on investigating vulnerability of fire-exposed reinforced concrete (RC) panels under transverse out-of-plane and compressive in-plane loads following a probabilistic methodology. The three-dimensional (3-D) RC panels are modeled by considering material and geometric nonlinearity and subsequent transient thermo-mechanical analysis is conducted for single-side exposure to fire loading. Uncertainties in the system are considered in structural capacity (material strength), heat transfer-, and fire model to study the stochastic thermo-mechanical response of the RC panels. The stochastic responses are studied in terms of central deflection, distribution of temperature, and variation in stresses and strains developed at the exposed and unexposed faces of the RC panels. It is concluded that the system uncertainty has significant influence on the duration of fire resistance of the RC panels under the considered thermo-mechanical loadings. The RC panels under the transverse out-of-plane loading exposed to fire are relatively more vulnerable as compared to the panels under the compressive in-plane loading. Moreover, the thicknesses of the RC panels have significant influence in determining the fire rating. Finally, it is recommended to use RC panels of at least 125 mm thickness irrespective of functionality if the desired code-specified fire rating is to be achieved.