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

The likelihood of any natural or man-made event preceding a fire is comparatively high, such as a fire occurring after a terrorist attack or any natural disaster such as a tornado, lightning strike, or earthquake. Structure is the one element that is consistent throughout all of these different hazard-fire interactions. In the present study, therefore, the response of a three-dimensional monolithic reinforced concrete (RC) dome structure under explosion loading followed by a fire event is analysed using a detailed Finite Element (FE) analysis in LS-DYNA®. The complete analysis is divided into three stages. Since explosion is a dynamic event whereas gravity loads and fire are considered quasi-static events, explicit and implicit solvers are alternately employed. Material data and equations governing the thermal and non-linear behaviour of RC structure from Eurocode 2 (EC2-2004) are used. Blast load is applied to the dome structure through LOAD_BLAST_ENHANCED whereas, fire load is applied as per ISO 834-10:2014. It is observed that an explosion followed by a fire significantly increases the structural damage. The major emphasis is to understand the behaviour of dome structure under such situations of combined blast and fire loading and showing the capabilities of FEM in these investigations.