Caisson Pipe is typically large diameter pipe that is used to create a watertight structure that enables contractors to work with greater ease within a body of water. Caissons are most commonly used to help with work on the foundations of bridges, damns, or are sometimes used in the assistance of repairing large ships. Because Caissons are very strong pieces of pipe, they can be perfect for either short or long term applications.
Smaller caissons are not as common, but they do exist. They can be used one at a time or in groups to carry different loads, such as a building column. Caissons are placed where they can be of most use, and that is always where they will have the best luck keeping soil from entering a structure.
There are a couple types of caissons that we typically use. The first is an open caisson. It is used in dry ground or around areas with a minimal amount of water. The second type is a pneumatic caisson. These caissons are interesting because they can come in many different shapes and sizes, but the commonality between all of them is that the tops are always closed. This is an important part of this caisson, especially when submerged, because it enables compressed air to enter which, in turn, keeps water and soil from getting into the bottom of the particular structure. Pneumatic caissons are used for two major projects that both involve different soil needs. The first is when soil is not to be excavated through open areas and the second is when soil requires the stability of balanced pressure.
During World War II, caissons (aka Phoenix) were a vital part of the temporary construction of the Mulberry Harbours, which were built with the Invasion of Normandy in mind.