The Use of Eurocode Model of Reinforcing Steel Behavior at High Temperature for Calculation of Bars Elongation in RC Elements Subjected to Fire

The Anderberg model introduced in Eurocode 1992-1-2 gives stress-strain relationships of reinforcing bars for high temperature values at multiples of 100oC. This model was based on tests performed at steady temperature conditions. Therefore, the elongation predicted by this model only accounts for simultaneous action of external load and high temperature. The steel free thermal strain is not included. However, reinforcement of RC elements exposed to fire is subjected to unsteady temperature conditions. This paper presents the Eurocode model in temperature-strain coordinates. The sum of elongations caused by stress and free steel thermal strain is shown against temperature for various stress levels. This model might be useful for estimation of reinforcing bars elongation during advanced analyses of RC structures exposed to fire.