The Strengthening Of The Tiefbunker Ceiling

When the plans for the construction of the Tiefbunker were submitted to Hitler, he accepted them with one alteration. He ordered the ceiling of the bunker to be reinforced with steel girders as a final layer of protection. This technique was known to him from the fortresses at the East and West wall. If the ceiling were to be damaged, the girders would prevent sections of concrete from caving in.