Caisson Foundation | Types of Caissons | Advantages and Disadvantages of Caisson Foundation
What is a caisson
It is used on the foundations of a bridge pier, for the construction of a concrete dam, or for the repair of ships. Caissons are constructed in such a way that the water can be pumped out, keeping the work environment dry
Caisson foundations, also called pier foundations, are prefabricated hollow substructures designed and constructed on or near the surface of the ground, sunk to the desired depth, and then filled with concrete, thus ultimately becoming an integral part of the permanent structure It has a watertight chamber open at the bottom and containing air under pressure.
Types of Caisson Foundation
The process of caisson foundation construction can be build using several types of caisson foundations. They include:
The types of caissons are pneumatic caisons, open caisons,monolithic caisons, box caisons, floating caisons, excavated caisons, etc.
Box Caisson Foundation
Box caisson is the type that is closed at the bottom but open at the top. They are built-on land, carried to the site through floating and sunk in the right positions. While sinking this type of caisson, concrete, water, or sand is filled in it. Box caisson is mostly used for hard strata and is available at shallow depth.
Excavated Caisson Foundation
This type of caisson is used on excavation sites. Complete use of these types of caissons can only be done when the need to build a strong foundation on an excavation site is quite high. Excavation caisson is cylindrical in shape and is filled with concrete when it needs to be used.
Floating Caissons Foundation
These types of caisson foundations are mainly used at harbors and ports. The floating caissons are prefabricated floating docks that have cylindrical cavities in them. Floating caissons plays a key role in facilitating the expansion of existing maritime facilities by constructing new and improved forms of commuting.
Open Caissons Foundation
Open caissons are box structures that open at both, the top and the bottom. This caisson is most useful when there is no firm ground support available at a higher depth. As a result, they are used on sandy soils and soft bearing stratum.
Pneumatic Caissons Foundation
These large cylinders or boxes are mainly used for underwater construction. It is suitable for carrying out work up till 12 m of depth underwater. It is also made of timber, concrete, or steel. The compressed air used in the construction pneumatic caissons helps in carrying out the foundation work in a dry space.
Caisson Foundation Construction Process
The process of caisson Foundation construction does not happen at the worksite. There is a whole process that goes into that takes place in the following stages:
- Deciding which type of caisson foundation will suit which site
- As per the specifications, fabricate it taking every requirement into consideration
- Transported the caisson elements to the actual site.
- Get in the water fix it the caisson base at the required depth
What Are the Advantages of Caisson Foundation?
- Caisson is effective even at deep depths.
- Costs for construction of caisson are lower than alternatives.
- It makes less noise and vibration during construction.
- It has High axial and lateral loading capacity.
- Caisson Can adapt easily to its’ environment, makes less noise and vibration during construction.
- Caisson Provides a high load-bearing capacity
- Caisson is more economical.
- The pile reduces the need for the cap.
- They can be easily transferred to different site conditions.
Advantages of Caisson Foundation?
- Caisson is highly sensitive to manufacturing processes.
- Caissons are not good at polluted places.
- Requires building experience and highly skilled laborers.