Caisson

A caisson is a hollow structure made of concrete, steel, or other materials that can be sunk into the earth. It used as the substructure for a bridge, a building, or other large structures. Caissons come in many sizes and shapes depending on their future use. The one shared feature is that their bottom edges are sharp so they easily can be sunk into the ground. These sharp edges are known as the cutting edges of the caisson.