A comparative numerical simulation study on blast response of reinforced concrete slabs subjected to fire

The paper deals with the determination of the load bearing capacity of a reinforced concrete slab when it is submitted first to fire and secondly to a blast load. The software Autodyn (Ansys) is used to perform the numerical simulations. This software permits to analyze transient phenomena such as an explosion, where material properties change very rapidly (milliseconds). On the other hand, fire does not change properties that fast. This is not compatible with the philosophy of softwares for transient phenomena such as Autodyn. The paper shows how to avoid this difficulty by the gradual change of material properties due to fire and in relation to the exposure time, which allows to find the proper input for the numerical blast analysis by means of Autodyn. Several numerical simulations are carried out and the comparison between the structural behaviour for blast with and without fire is also presented. The mayor conclusion of this analysis is that dynamic behavior of structural elements due to blast is not much altered by the exposure to a 30 min of standard fire when both loads are on the same side of the structural element.