Modelling of Steel Creep at High Temperatures Using an Implicit Creep Model

Abstract

The paper presents the numerical procedure for modelling the behaviour of steel structures at high temperatures using a newly developed implicit creep model. This implicit creep model uses the calculated creep strains to modify the material stress-strain curves, thus implicitly taking into account the effect of the developed creep strain. The newly calculated stress-strain curves are modified by stretching the initial temperature-dependent stress-strain curves using the calculated values of the creep strain which depend on the level of temperature and stress that the section of structure is being exposed to during fire. The implicit numerical procedure has been implemented in a previously developed numerical model for predicting the behaviour of structures under fire. In order to test the validity of the newly developed implicit creep model, an in-house fire experiment was performed. Results of the experiment have shown a good agreement with the model predictions indicating the validity of the developed implicit numerical procedure.