If you have a construction project taking place on, or in, the water, you’re going to need the service of a caisson. Let’s take a moment to look a little closer at why caisson construction is so important.
What Is Caisson Construction?
A caisson is a watertight structure which is used as an “anchor” for a foundation. Think of it like this, you need to build a pier. That pier can be floating or fixed. If it’s a fixed pier you’ll use a caisson as the base of the structure on the floor of the body of water.
Why Would You Use a Caisson?
A caisson can be a critical component of any construction project because it provides stability. Where the ground can, and will, shift under the weight of a new structure, a caisson can be used to distribute its’ load evenly. This helps the building to not settle differently depending on how the soil fluctuates underneath it but, instead to provide an even “cushion.”
What Are Caissons Made Of?
Caissons are generally constructed of concrete, steel, or wood. As with any construction project, the material to be used will depend on the function of the caisson and the type of caisson being constructed.
What Types of Caissons Are There?
There are several types of caissons.
Pneumatic caissons have a compressed air system built into them so that they can keep water out during placement.
On the opposite side, we have box caissons which are exactly what you might expect – watertight boxes with an open top that can receive the pier when it’s in place.
Open caissons are best used in areas that have soft clay and minimal potential for obstructions to appear. Open caissons do not have a top or a bottom.
Excavated caissons are simply caissons that are being used inside of an excavated worksite.
Also known as a floating dock, a floating caisson is important in ports and harbors as it can meet a need that can not often be forecast. Floating caissons can be prefabricated and essentially put on “standby” for use as required.
What Concerns Are There When Using Caisson Construction?
Some of the work will need to be completed underwater which requires a special skill set. It can be difficult to locate the needed inspection team.
The construction process for a caisson is one that needs extra attention. Trained divers will be needed on-site.
What Are the Benefits of Caisson Construction?
- Effective even at deep depths.
- Costs for construction are lower than alternatives.
- Can adapt easily to its’ environment.
- Provides a high load capacity.
Caisson Installation
There are a number of ways that a caisson can be installed. Some are built and installed on-site while others can be built off-site and then moved (generally floated) to their installation site.
Placement and caisson type will dictate how installation should be handled. At times, the placement location will need to be prepped. This is when a cofferdam is constructed.
A cofferdam is sometimes used as a way to clear an area so that a caisson can be implemented. A cofferdam is essentially a pair of dams that would sit on opposite sides of each other.
Their intent is to cut off the water supply to a particular area and, in turn, create a dry space. These are temporary structures, built to assist, not to be used as a long-term solution.
You should now hopefully have a better understanding of how a caisson can be used in construction as an essential building block. Hopefully you also understand how important it is to have those caissons constructed and installed by an experienced team