Look at any 40ft steel container and you’ll see those distinctive ridges on the outer walls. Some call them ribs; others call them waves.
But there’s actually a technical name for the ridges: The steel is referred to as “corrugated.”
Corrugated steel serves a very important purpose. By adding the ridges, the steel’s strength is maximized. In fact, without the corrugated ridges, sea crates wouldn’t be able to be stacked dozens of units high. The containers at the bottom of the stack would crumble under the weight.
So why are corrugated steel walls stronger and sturdier than non-corrugated steel? The science behind corrugation is fascinating, and we see it all over – from “corrugated” palm tree leaves, to our habit of folding slices of pizza to stiffen them when we eat.
How Does Corrugation Add Strength to Sea Crate Walls?
Corrugated steel has been in use since the early-1800s, and today it’s widely used in construction. We have corrugated steel (and aluminum) siding on our homes. Metal roofs are built with corrugated steel. And many aluminum and steel pipes are corrugated.
The reason, of course, is that corrugation adds strength to any material.
How? Corrugation increases the material’s stiffness. You can do a quick experiment to understand the principle. If you built a “bridge” made from a single sheet of paper between two books, the paper bridge wouldn’t be able to hold much of anything. An ink pen would cause the bridge to bend and collapse.
Now, if you “corrugated” the sheet of paper (i.e. folded it into a zig zag pattern) and placed it back over the books, your paper bridge can now hold a full can of soda. That’s the power of corrugation.
In other words, adding curvature to a flat object increases its rigidity (as explained by Wired magazine).
That’s why when you hold a piece of hot pizza flat, the tip of the slice wants to droop. But when you fold the slice, it stiffens up. You’ve added curvature, and the slice becomes stronger.
With shipping containers, corrugated steel walls maximize the strength of the container. That’s why you can stack dozens of containers on top of each other, without any structural damage. In fact, corrugated steel has one of the highest strength-to-weight ratios of any building material; it’s super-lightweight but extremely resistant to collapse.
Shipping Container’s Corrugated Steel Walls: Additional Benefits
In addition to corrugated steel’s high strength, the material offers a range of other key advantages that make it ideal for sea crate construction. These benefits include:
- Rust Resistance: Corrugated steel is almost always galvanized during fabrication. This means a thin layer of zinc is added to the steel’s outer layer. Zinc increases the steel’s resistance to rust, which can be further prevented by painting the surface evenly.
- Dent and Buckle Resistance: Corrugated steel is sturdy, which makes it ideal for shipping. It’s more resistant to dents than standard sheet steel, and its increased rigidity prevents buckling. In 40ft shipping containers, for example, corrugation increases wind resistance; without corrugation, the walls of a 40ft container would be more likely to buckle in high winds.
- Low Maintenance: Finally, corrugated steel tends to require little maintenance. The steel walls may just require cleaning. That’s why steel shipping containers tend to stay in circulation for 15 years or more.
There you have it: Corrugated steel isn’t used because it looks cool. It serves a very important purpose in sea crate design: Those ridges add strength, prevent dents, and enable containers to be stacked dozens high.
Do you need a shipping container for storage, shipping or a residential build? K&K Containers can help. We offer a wide selection of ISO shipping containers for sale. Contact us today for a FREE estimate.