What Types of Foundations Are Most Common in Building Designs?

No matter what type of structure you are creating, it’s crucial to get the foundation right. There is a wide range of foundations to choose from, and the kind that works best for you will depend on the size and design of your building, where it is located, and the type of soil it is resting on. Below, we’ll take a look at the most common kinds of shallow and deep foundations to help you better understand which type will work best for your next project.

Shallow vs. Deep Foundations

Before we dive into the specific kinds of foundations that you have to pick from, it’s important first to discuss the differences between the two main categories of foundations: shallow foundations and deep foundations.

Since they are more economical and adequate for most applications, shallow foundations are defined as ones that measure one to three meters deep from the natural grade level and are the most common type used today. In cases where the soil’s strata are too deep to reach with excavation and matters where the ground is too soft or has too low of a bearing capacity, deep foundations are required.

Types of Shallow Foundations

There are a few kinds of shallow foundations. Let’s take a closer look:

Isolated Footing

Isolated footing foundations are the most popular type of foundation and rely on concrete pads to support an individual column. These are ideal for lighter structures, but a more reinforced foundation may be needed for larger buildings.

Combined Footing

Combined footing foundations are very similar to isolated footing because the pads of concrete are more extensive and meant to support more than a single column. These kinds are ideal for situations where the foundation columns are too close to help each one with an individual pad.

Strap Footing

In a strap footing foundation, isolated concentric and eccentric footings are connected via a strap beam. This strap beam is designed to even out the distribution of soil bearing pressure in cases where eccentric footings are required due to space restrictions.

Strip Footing

A strip footing foundation entails creating a steady base that supports a load-bearing wall. This concrete strip is typically twice the wall’s width that it bears but can be even more comprehensive in specific applications.

Raft Foundation

A raft foundation, otherwise known as a mat foundation, is made up of thick concrete that supports the structure’s entire weight. Raft foundations are the sturdiest type of shallow foundation and are used for larger buildings with a heavy column load.

Types of Deep Foundations

Just like shallow foundations, there are various kinds of deep foundations. They include:

Driven Piles

A driven pile foundation is built by driving either concrete and steel H-beam piles or tubular steel piles deep into the soil to support the foundation’s weight. This is the most affordable type of foundation but may not be applicable in areas where the ground has boulders or rocks.

Continuous Flight Auger Piles

A continuous flight auger (CFA) pile foundation is built by drilling holes into the ground before quickly filling gaps with poured concrete and reinforcing the concrete piles with a pre-arranged cage forced down over the wet concrete. Since CFA piles do not require soil compression, they tend to offer a higher bearing capacity when compared to driven piles.

Bored Piles

Bored pile foundations are the most common type of deep foundation built by boring holes in the soil before placing a pre-constructed concrete pile into them. Since the banks are placed in a pre-bored spot rather than driven directly into the ground, noise and vibration are less of a concern, making bored piles better suited for rocky areas.

Mini Piles

Mini piles are a form of bored piles that are smaller in diameter, which makes them suited for confined spaces where a high load-bearing capacity is not required.

Let e2 engineers Help You Design the Ideal Foundation for Your Building

If you still aren’t sure which type of foundation is best for the building you are constructing, e2 engineers can help. To learn more about how our expert team of structural engineers can help you with your next project, be sure to contact us today!