What is a Larssen Interlock?

Larssen interlocks is the type of sheet pile interlocks with indented and outdented designs that interlock with each other to create wall structures for applications like retaining walls, bridge construction, oil terminals, protection for coastlines, piers, and more. The wall structures that Larssen interlocks create are great for protecting areas from flooding, slumping, and wave damage. In addition to being designed to make interlocking simple and easy, Larssen interlocks are also engineered to be strong, durable, and resistant to bending. Larssen sheet piles are most often made of steel or some other type of metal.

Larssen Interlocking System: Hot Rolled Sheet Pile

A Norwegian engineer named Tryggve Larssen invented Larssen interlocks in the early 1900s. They were one of the first kinds of hot rolled sheet pile. Hot rolled sheet pile is made by applying high temperatures over 1,200⁰C to solid steel, pre-rolled steel, or other metals. Once heat is applied, the piles are stretched into desired interlocking shapes.

Some of the advantages of hot rolled sheet pile include:

Durable interlocks that can be used and re-used while maintaining their strength

• Thick piles that can easily be driven into hard ground

• Interlocks attach tightly, providing maximum protection against water seepage

An alternative to hot rolled sheet pile is cold rolled sheet pile, which has a different production method and results in a bent-plate interlock. Cold rolled sheet piles are produced in greater numbers and are often cheaper, but they are typically thinner, less durable, and do not interlock as tightly as Larssen interlocks.

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Common Types/Styles of Larssen Interlocks

AZ –

A type of sheet pile with a consistent thickness of flange and web that is corrosion-resistant and thick.

NZ –

Similar to AZ in terms of design profile but more lightweight; unlike many other Larssen interlocks, NZ piles are manufactured in the U.S.

ZZ –

A lightweight style... webs have 0.375-inch thickness and flanges have 0.379 thickness.

Hoesch –

The design of Hoesch piles is optimized for efficient pile driving.


A type of sheet pile with consistent thickness of flange and web that is specifically designed with deep-profiled sections featuring a continuous web for optimizing shear load transfer.

Buying and Selling Larssen Interlocks

As we previously mentioned, one of the advantages of hot rolled piles like Larssen interlocks is that they are built to be durable and engineered to be used and re-used. If you’re looking to buy Larssen interlocks, you have both new and used options, and most used options are in excellent shape and priced affordably. You may decide buying new is best if you can’t find exactly what you need on the used market. Typically, though, there’s a wide selection of used options at any given time.

On the other hand, if you have used or surplus Larssen interlocks taking up space after a project is complete, it’s a great idea to consider selling them. Sheets with Larssen interlocks are hot ticket items.

Buy and Sell with Eiffel Trading

We are known for our structural steel inventory, and used sheet pile is our specialty! Our used sheet pile selection includes sheets with Larssen interlocks (AZ/ZZ/NZ/Hoesch sheets), as well as PZ/PZC sheet pile, PS sheet pile, cold rolled sheet pile, and more. In addition to sheets, we also offer used pipe pile, used steel plates, brand new h-pile beams, and more.

All of our listings are constantly being updated, but if you don’t see what you’re looking for, create a wanted listing for free.

Ready to sell your used heavy equipment or construction material? List your products today for free on Eiffel Trading’s online marketplace.

If you have any questions or would like additional information, please call us at 1-800-541-7998 or email sales@eiffeltrading.com.