Prediction of Behaviour and Failure of Steel Columns Subjected to Blast Followed by Fire Induced by Explosion

Abstract

When a structure is subjected to an explosion, high blast pressure is initially released during a very short period of time and is followed by fire. The combined effects of blast and fire may cause damage and failure of one or more key elements of the structure leading to progressive collapse and failure of the entire structure. However, design procedures suggested by current standards and codes do not consider the combined effects of blast and fire because of the complexity of the problem, which involves inertia and heat effects with high geometrical and material nonlinearities. The ultimate aim of the present study is the numerical and analytical prediction of the behaviour and failure of steel columns subjected to blast pressure followed by fire. A new numerical model was developed and validated to perform both dynamic and transient thermal analyses simultaneously using the dynamic fully coupled thermal-displacement analysis procedure within ABAQUS/explicit. The proposed numerical model was validated against published experimental test results. The study also proposes a new simplified approach for analysing the combined effects of blast and fire on the response and critical temperature of steel columns. The suggested approach implements the single degree of freedom analysis method (SDOF) in conjunction with the resistance function of steel columns at elevated temperature. The proposed analytical method has been validated against published experimental results in addition to numerical simulation results conducted in this study, and the validation has shown very good correlation between the results. The validated analytical approach can be used in the preliminary analysis and design of steel columns under blast and fire.