Structural Performance of Reinforced Concrete Walls under Fire Conditions

This paper investigates the structural performance and deterioration of the load-carrying capacity of reinforced concrete (RC) walls subjected to one-sided fire. Heat transfer analysis is conducted for characterizing the temperature gradient within the wall and a structural model is developed. The model considers the transient creep of concrete under fire, strain softening in compression, cracking and tension stiffening, yielding of the steel reinforcement, and the effect of geometrical nonlinearity. The heat transfer analysis is conducted using a finite-element approximation, and the governing differential equations of the structural model are solved using the nonlinear shooting method following an iterative procedure. A numerical example that shows the capabilities of the proposed model and clarifies the failure mechanism of RC walls in fire is presented. Parametric studies on the influence of important fire design parameters are conducted. Finally, the model is validated through comparisons with test results from the literature. The results show a buckling failure of RC walls subjected to one-sided fire and clarify the importance of the effects of geometrical nonlinearity. It is also revealed that the existing codes can be nonconservative in many cases. (C) 2020 American Society of Civil Engineers.