Along the route from Ramouville to Flainville you find 8 shelters at a row. At the coast, near Quiberville, a training site for Flak was operational. These shelters might have given lodging for the students.
Your first impression is that they are big.
In the construction they used corrugated iron, but now in a thin version.
Here a piece of the shuttering remains.
The concrete above has also a light reinforcement.