Metal Retaining Walls: Purpose, Use Cases, & More

March 7, 2023 | Categorized in:

steel retaining wall along hilly terrain

When it comes to steel piling, retaining walls are one of the most common applications we see. However, many people don’t realize how many different types of retaining walls there are, and the flexibility that these different types enable. Let’s discuss what retaining walls are, what they’re not, and some problems that they’re ideal solutions for.

What is a retaining wall?

Starting with the basics, a retaining wall is a structure that holds (or retains) soil, sand, or other similar material behind it. By doing this, a retaining wall prevents issues like downhill erosion, rockslides, and more. These walls can be anchored in place in a number of different ways that we will discuss, but they all are rigid and act to keep earth in place that would not naturally do so.

What materials can they be made from?

The three major materials that retaining walls are commonly made from are wood, stone/concrete/brick, and metal. Wood is arguably the cheapest material of this group, but can only be used in loose soil that is easy to drive into. Anything that is course-grained will make it nearly impossible for wooden pieces to penetrate. The other downside of wood is that it’s very susceptible to rot, termites, and other forms of decay that can quickly destroy the wall. All of these will depend on the soil conditions, so make sure that you check these factors before deciding if wood is the best solution.

Most commonly used for gravity retaining walls (which we’ll discuss more in the next section) due to their weight and density, stone or concrete retaining walls are often seen in gardens and other natural landscaping environments. Beyond their weight being used for gravity retaining walls, the primary benefit of stone or bricks is their aesthetic appeal, which is why they are so popular in backyards and similar locations.

Finally, steel or other metals are primarily used for piling retaining walls, and are a cost-effective solution while still being durable for decades. Because of this, steel is one of the most common materials for both temporary and permanent walls, and is strong enough to withstand immense forces from the soil it is holding back.

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Types of retaining walls

We mentioned a few different types of retaining wall variations in the above section, so let’s define the kinds you’ll see most frequently:

  • Gravity retaining walls – as alluded to above, gravity walls use their weight alone to hold the soil back. Generally, a small trench will be dug that the wall sits in, and simply the mass of the stones, bricks, or concrete will prevent it from being pushed or toppled.
  • Piling retaining walls – typically made from sheet piling, these walls are driven into the ground and are great options where space is an issue due to their thinness. Sheet piling is also fairly flexible in the ground material it can be driven into, so they’re commonly used in a variety of applications.
  • Cantilever retaining walls – shaped like an L or upside-down T, these are often made from concrete and the weight of the soil (rather than the wall) actually holds down the “heel” of the wall. This prevents the exposed pieces of wall that holds back the soil from toppling, and additional buttresses can be added for even more strength and rigidity.
  • Anchored retaining walls – these consist of a primary wall piece that is held in place by anchors driven into the soil behind the wall. These anchors are attached by cables and get expanded once in place to keep them there and prevent slipping.

Retaining wall vs. bulkhead wall

While sometimes used interchangeably, there are some differences between these two types of walls. Both are used to retain material, but a retaining wall typically has earth on both sides, while a bulkhead wall has earth on one side and water on the other. Retaining walls can also sometimes have water on one side, but this is usually only for temporary applications such as cofferdams.

What are retaining walls used for?

As we mentioned at the beginning, there are a wide variety of applications these walls can be used for. Steel walls in particular span both temporary and permanent uses, which adds an extra layer of flexibility.

Prevent soil erosion & flooding

One of the major uses for all retaining walls, no matter the material, is to prevent the erosion of a hill and control flooding. By holding the bottom of a hill in place to prevent sliding and strategically controlling where runoff water goes, both of these common problems can be handled with one solution.

Temporary cofferdams

When an area covered by water needs to be excavated or worked on, a cofferdam is used to hold back water while pumping the water within the area out. Steel sheet piling is by far the most common way this is achieved due to its strength, corrosion resistance, and ease of installation. Other forms of piling such as H piling can also be used for this application.

Permanent terrain support

While cofferdams are short-term installations, piling can also be used for long-term support of terrain, particularly around roads. Similar to preventing corrosion and flooding, some soil is too unstable or weak to hold its own weight and can lead to massive disasters. In these cases, retaining walls are used to help the material stay in place.

Protection from rockfalls

On the subject of unstable terrain, you’ll often see some form of retaining walls along roads or highways that run by rocky walls or hills. Sometimes their purpose is to support terrain, but an important application of these is also to catch any rocks that might fall and get near or on the road. Because some of these walls only have to fill this role and not necessarily hold tons of earth in place, they can be less heavy-duty.

Basement walls

Another reason that soil might need to be held back is to reinforce underground structures like basements or underground parking garages. Retaining walls can be used here to strengthen the walls and prevent them from cracking or buckling.

Strengthen your projects with steel retaining walls

Whether you’re looking for piling retaining walls for temporary or permanent uses, Service Steel can supply your projects. Our steel piling is used for strong foundations across the country, and we have a team of experts standing by to help with any questions or concerns you might have. Call our team or request a free online quote today!