Caisson Foundation in Construction: Definition, Types, Process & Advantages Explained by Stonedge Construction Pvt Ltd

What Is Caisson Foundation? Types, Process & Advantages || Types of Foundation in Construction: A Complete Guide || Caisson Foundation: Types, Advantages and Disadvantages || Types of caisson foundation

A Caisson foundation also called as pier foundation is a watertight retaining structure used as a bridge pier, in the construction of a concrete dam, or for the repair of ships. It is a prefabricated hollow box or cylinder sunk into the ground to some desired depth and then filled with concrete thus forming a foundation.

There are varied types of caisson foundations, each with different benefits and uses. Some types are

This type of caisson foundation is open at both the top and bottom and is sunk into the ground using its weight. This is best suited for areas with firmer soil.

This is pre-constructed over the ground like a box with the bottom closed and sunk into the earth. It is then filled with concrete to form a solid foundation. This comes into play when excavation is difficult.

This type of caisson foundation is closed at the bottom and then air- air-pressurised to allow workers to work below the water level. It is best suited for sites with soft soil.

Monolithic caissons are solid structures made of concrete or steel. Unlike other caissons, they do not have joints and are mostly built as a single piece. They are used in places where a strong and solid foundation is crucial and needs to withstand corrosion and wear. These caissons are used for the construction of large and high-load-bearing structures, bridges, and offshore platforms.

A Caisson foundation can be constructed on the dry bed or after making a sand island. At a location where the depth of water is greater than 5 m to 6 m and the velocity of water is high.

Well can be fabricated on the river bank and then floated to the final position and grounded. Once the well has touched the bed, sandbags are deposited around it to prevent scour.

The well may sink into the river bed by 50 to 60 cm under its on weight. Further sinking operation is similar to the sinking of a well in a dry bed.

The well is sunk into the ground to the desired level by excavating through the dredge holes.

Caissons are economic.

It is environment-friendly. There are slightly less sound pollution and reduced vibration.

It is easily adaptable to varying underwater soil conditions.

Caisson has high horizontal and lateral loading capacity.

Minimum handling equipment is required for placement of reinforcement cage.

It is sometimes used in types of soils where driving pile could not penetrate.

Caissons can be reached to great depths.

There is a direct and effortless way to go to the bottom of caissons to remove any kind of obstruction.

Quality control of pneumatic caisson is good as it is built on dry conditions.

Disadvantages of Caisson Foundation

Construction of caisson foundations is time-consuming compared to shallow foundations.

High initial cost is involved due to specialized equipment, skilled labor, and construction methods.

Pneumatic caissons may pose health risks to workers due to compressed air, such as decompression sickness.

Construction becomes difficult in unstable soil or strong water currents, especially in riverbeds.

Requires experienced supervision and skilled manpower for safe and accurate execution.

Inspection and repair after construction are difficult, especially at great depths.

Not suitable for small or low-load structures due to economic inefficiency.

Risk of tilting or sinking unevenly if soil conditions are not properly assessed.

Weather conditions and groundwater levels can delay construction progress.