In 1968, the first sound wall was built, situated along Interstate 680 in Milpitas, California. For the last half century, sound barriers have cropped up along turnpikes and highways across the country. And even though caisson construction has been around for practically hundreds of years, its modern implementation for projects like sound walls is a more recent development—one that has made this type of construction much more effective, sturdy and economical.
Depending on the nature of your upcoming construction project, caisson drilling just might be the most suitable option for the foundation work. In order to approach your plans from an informed perspective, it’s necessary to understand the nature of caisson drilling and make some important considerations. This article provides fundamental insights to help you get started.
What is caisson drilling and construction?
Let’s begin with the basics.
As it pertains to construction, a caisson is a foundation-anchoring structure that consists of an air- and watertight chamber. The word itself comes from the French term caissa, which means “box.” Generally made of concrete, steel or wood (depending on their specific category and function), these rectangular or cylindrical boxes serve as a substructure to the main construction, effectively positioning and stabilizing the foundation.
Caisson drilling is the particular method by which foundational caissons are drilled into the ground to be filled with reinforcing materials, like concrete. With this type of drilling, weight-bearing caissons are able to reach as far down as the bedrock beneath water and soil, thereby enabling construction teams to create a sturdier base for massive structures above.
The caisson drilling process minimizes the risk of uneven weight distribution and vertical shifting that can occur when the surrounding soil settles—a critical concern in preventing major structural damage or collapse. Leveraging this method, construction professionals are able to create a caisson foundation that securely supports structures of significant size, weight and height.
Drilled caissons, which are also sometimes referred to as drilled piers, drilled shafts or bored piles, are an effective solution for creating sturdy foundations that support structures with extensive axial and lateral loads. This solution is particularly useful and widely leveraged for construction projects like highway sound-barrier walls and high-security fencing.
Because the drilled caissons can be installed in a wide range of soil and rock conditions to depths of more than 300 feet, featuring diameters of anywhere from 2 to 12 feet, they provide valuable support to projects that require a combination of side friction and end bearing resistance.
What are the distinct benefits of caisson drilling?
So, what exactly is it about caisson construction that makes this option advantageous for certain foundation needs? Following are some of the most notable considerations.
- Versatility: Caisson drilling can be applied to construction projects in varied locations and environments. Caissons are highly adaptable to different types of work sites and can be easily transferred from one place to another.
- Stability & Load Capacity: In major construction projects requiring the fortification of heavy loads, particularly when there is potential for ground shifting, caisson foundations are vital stabilizers. Caissons provide the support necessary to distribute weight evenly and prevent any settling that might occur due to soil fluctuations. They are sturdier than traditional foundation pads and provide greater strength for both axial and lateral loads.
- Affordability: Contrary to some assumptions about this process, caisson installations are typically more economical than the implementation of massive concrete pad foundations. In some cases, they negate the need for (and expense of) pile caps. In large, complex construction projects, this option can be a significant cost saver.
Of course, it is essential to keep in mind that caisson drilling must be performed by highly experienced builders and skilled laborers. Be sure to partner with qualified professionals to manage this process safely and effectively.