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Concrete, at the heart of Thiot Ingénierie’s expertise: far-field blast [2]

By 4 January 2021 No Comments

Concrete’s vulnerability is still relevant, whether in case of impact or blast-type threats, given the multiple uses of this material in buildings and infrastructures. How to predict the perforation by a missile or a warhead of a structure composed of several reinforced concrete slabs? How to assess the resistance of a wall to blast induced by an explosion ? These are the questions Thiot Ingénierie is faced with in order to provide the most reliable answers possible to its clients.

Concrete, or more generally concretes, fall into the family of geomaterials and as such are complex materials: they are heterogeneous on the scale of the studies and their properties vary according to the weather and climatic conditions. The study of the behaviour of these materials under dynamic loadings is therefore a “matter for experts”. The strategy implemented in our laboratory to meet our customers’ needs is based on a synergy between tests, calculations and characterisation experiments.

In the case of the response of reinforced concrete infrastructures submitted to blasts, it is the restitution of the damage and rupture of the material that is decisive in the overall behaviour of the structure. Our experts have thus defined a strategy for characterising the behaviour of concrete in the range of stress considered during an explosion. The data gathered during these characterisation tests made it possible to identify the important parameters leading to a reliable restitution of the phenomena of the performance of concrete when it is subjected to blast.

Reinforced concrete infrastructures submitted to blasts
Riedel & al. 2010

An illustration of our know-how in this field is shown in the figure below, which represents a comparison between experiment and calculation, for a far-field blast applied to a reinforced concrete slab. These simulations performed with the IMPETUS AFEA software highlight the complexity of this type of multi-physical calculation, which must both generate the correct source term applied to the structure (pressure history) and restore the correct deformation, then the rupture of the concrete and its reinforcement.

In the next edition, the blast in nearby fields.

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