CAISSON STRUCTURES BASIC INFORMATION AND TUTORIALS

Caissons are box-like structures which are similar in concept to cofferdams but they usually form an integral part of the finished structure. They can be economically constructed and installed in water or soil where the depth exceeds 18„000.

There are 4 basic types of caisson namely:

1 . Box Caissons

2. Open Caissons

3. Monolithic Caissons

4. Pneumatic Caissons

The first three(3) used in water, usually of precast concrete and used in water being towed or floated into position and sunk. The last one is for land caissons of the open type and constructed in-situ.

Pneumatic Caissons ~ these are sometimes called compressed air caissons and are similar in concept to open caissons. They can be used in difficult subsoil conditions below water level and have a pressurised lower working chamber to provide a safe dry working area.

Pneumatic caissons can be made of concrete whereby they sink under their own weight or they can be constructed from steel with hollow walls which can be filled with water to act as ballast. These caissons are usually designed to form part of the finished structure.