Top Ten Questions About Sheet Piling

1.  Sheet piles are recyclable and reusable.
2.  Piles can come in a wide range of lengths, size, and steel options.
3. They can be used for temporary and permanent structures.
4. They can be installed using silent and vibration-free methods.
5.  The work is neat, clean, and creates no spoil arisings. The supervision of work on-site can be reduced, and minimal storage space is required.
6.  Sheet piling is a more cost effective and quicker installation than contiguous or secant walls.
7. Cofferdams can be constructed in almost any desired shape, however, for practical and economic reasons, most cofferdams are either rectangular or circular.
8.  Sheet piles can provide a close-fitting joint to form an effective water seal.
9.  They have a long life above and below water, making them advantageous for marine and coastal projects.
10. Anchored sheet piled walls can provide even more flexibility for installation purposes.

Steel itself is a waterproof material so a sheet pile wall is watertight other than at the intersection of the steel sheets. If the solution needs to be watertight, the sheets can be secured via sealant or welding in order to ensure no water can pass through. The water flow through sealed interlocks can be calculated with a practical design method backed up by several in-situ full-scale tests.

Sheet piling can be designed as a temporary solution. The nature of the long steel sheets means they can be easily extracted and reused, serving to retain whilst other construction work continues. If the wall is designed to be permanent, the piles can have a design life of up to 125 years, but this is dependent on the environment within which they are installed.

The “standard” sheet pile was the 400 – 420mm wide U pile for several decades in the UK

Converting from a narrow, inefficient pile to a wide modern pile can save up to 27% on weight whilst offering equivalent driveability and strength.

In the 1980s, the 525mm wide range overtook the older sections, offering much higher strength per unit weight but with reduced capacity to withstand sub-optimal driving practice. The 600mm wide U pile was initially resisted because of fears over driveability, but the efficiency and need to compete with Z piles soon overcame these reservations. The 600mm wide U pile is still the standard temporary works pile today.

Larssen PU12 – 600mm width

Arcelor Mittal AZ – 630mm width

ArcelorMittal AU – 750mm width

Today we see even wider piles with U piles up to 750mm wide and Z piles up to 800mm wide. These piles offer maximised economy (optimised strength to weight ratio) but have clever additions such as strengthened shoulders to ensure driveability is not compromised.

To achieve the full performance of your structure, your sheet pile wall must be driven to the depth specified by the wall designer. This can be achieved through a number of methods – vibratory hammers, impact hammers, or a silent press if noise and vibration need to be eliminated. Corner and connector pieces are available for any sheet pile purchased, allowing the wall to follow the line laid out in the design.

See a video of a pressed sheet piles being installed here