Multi-hazard analysis of a reinforced concrete structure under blast and post-blast fire

The likelihood of fire following a natural or man-made event is comparatively high, such as a fire occurring after a terrorist attack or any natural disaster such as a tornado, lightning strike or earthquake. A structure is the one element that is consistent throughout all these different hazard–fire interactions. In this work, the response of a three-dimensional monolithic reinforced concrete (RC) dome structure under explosion loading followed by a fire event was analysed using detailed finite-element (FE) analysis in LS-Dyna. The analysis was divided into three stages. Since an explosion is a dynamic event and gravity loads and fire are considered quasi-static events, explicit and implicit solvers were alternately employed. Material data and equations governing the thermal and non-linear behaviour of RC structures from BS EN 1992-1-2:2004 were used. A blast load was applied to the dome structure through Load_Blast_Enhanced in LS-Dyna. Fire load was applied as per ISO 834-10:2014. The results showed that an explosion followed by fire significantly increases structural damage. The major aim of this work was to understand the behaviour of a dome structure under combined blast and fire loading and to show the capabilities of FE analyses in such investigations.