A limit analysis approach to the stability assessment of reinforced concrete panels in fire conditions

Abstract

The present study investigates the stability conditions of reinforced concrete panels subjected to fire loading within the framework of limit analysis theory. The method relies in a first step upon the preliminary determination of the temperature dependent interaction diagrams of the structural element. Interaction diagrams derived from the static approach are shown to depend on the geometry of panel cross-section as well as on the strength properties of the constituents, which degrade continuously as fire proceeds. The second step of the method consists in determining the deformed configuration of panel from the analysis of thermo-elastic equilibrium of the structure. The stability analysis and design of the panel in its deformed geometry are then carried out by comparing the distribution of internal efforts to its reduced strength capacities expressed by means of the associated interaction diagrams evaluated in the first step. Several numerical examples are presented to assess the effect of relevant parameters on the overall fire safety of the structure, emphasizing the effectiveness of the approach for design purposes.