Evaluating the Response of the Steel Bending Frame Against Fire After the Explosion

Fire and explosion are often synergistic. A fire may occur after an explosion or a fire may occur first and then an explosion occurs. The consequences of a combined fire and explosion scenario about each component must be considered in the design or evaluation of the structure. The analysis of fire and explosion should be done together and the effects of one on the other should be carefully analyzed. In most researches and design guidelines, fire and explosion phenomena are investigated independently and their interaction is less considered. In this research, this issue is addressed and the fire after the explosion and the interaction and synergy of these two phenomena are studied together. The studied structure is a two-story steel structure with different occupancy (dwelling, office, etc.). which is subject to various explosions and as a result fire caused by the equipment inside the building. Explosive loading has been calculated using UFC 3-340-02 instruction charts and fire load using the concept of fire density and relationships of EUROCODE 1 and EUROCODE 3 regulations. In order to simulate explosive and thermal loading, Abaqus finite element software and combined thermal-deformation dynamic analysis have been used. The temperature caused by the fire has been used as a natural fire, and the cooling and post-cooling stages of the fire have also been investigated. After validating the proposed simulation with two valid laboratory works, the analysis of the structure's response against various types of explosive loads and subsequent fires was performed by a numerical model. The results of these investigations showed that the response and deformation of the structure in the chain combined analysis (applying the interaction of explosion and fire on the structure) compared to the independent combined analysis (independent analysis of the structure against explosion and fire and collecting the responses together) It increases by 15%, and considering the interaction of explosion and fire is not only important but also necessary, and not considering this interaction in most cases will cause the response of the structure to be less than the reality, and as a result, it will cause an unsafe design.