Blog - Dmidrilling.com Construction and Drilling - Important Concepts That Everyone Should Know PIERS A pier is a raised structure in the body of water, which is supported by the piles or pillars. Piers support bridges, buildings and walkways. There are different types of piers such as: working piers, pleasure piers, etc. All of them possess different purposes. It is a structure which is built on posts extending from land our over water and are used as a landing place for ships, entertainment area, etc. It supports the ends of adjacent spans. CAISSONS A caisson is a watertight retaining structure. It is a cylinder or hollow box that is sunk into the ground for a definite depth by auguring a deep hole into the strata. This is mostly used for constructing bridge piers and other foundations that are located beneath bodies of the water. Caisson is used to work on the foundations of a bridge pier, construction of a concrete dam and also for the repair of ships. These are constructed so that the water can be pumped out so as to keep the working environment dry. Caissons can be easily put in place, no matter where the structure is being constructed. DEWATERING Dewatering is the removal of ground water from the soil for favorable condition of any construction. It aims at lowering the ground water level and is used to remove or drain the groundwater from a construction site, caisson, or mine shafts, either by pumping or evaporation. It removes the unwanted water from the ground from any work area, thereby helping to make the drilling process easy.