Influence of Creep on the Stability of Steel Columns Subjected to Fire

This paper presents highlights of on-going research, which aims at developing analytical, computational and experimental predictions of the phenomenon of creep buckling in steel columns subjected to fire. Analytical solutions using the concept of time-dependent tangent modulus are developed to model time-dependent buckling behavior of steel columns at elevated temperatures. Results from computational creep buckling studies using Abaqus are also presented, and compared with analytical predictions. Material creep data on ASTM A992 steel is also presented in the paper and compared to existing creep models for structural steel. Both analytical and computational methods utilize material creep models for structural steel developed by Harmathy, and by Fields and Fields. Predictions from this study are also compared against those from Eurocode 3 and the AISC Specification. It is clear from results presented in this paper that having an accurate knowledge of material creep is essential in predicting column buckling behavior at elevated temperatures. There is clearly a need for more extensive and reliable creep data for structural steel. Most importantly, results show that neglecting creep effects can lead to significant errors in predicting the strength of steel columns subjected to fire. 

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