Choosing the right steel sheet pile is crucial to the success and speed of piling projects, especially in foundation and retaining wall applications. Cold-formed sheet piles have become popular in many construction environments. This article covers the types, applications, technical properties, durability options and installation methods to help you choose the right sheet piles.
Difference Between Cold-Formed and Hot Rolled Steel Sheet Piles
Cold-formed sheet piles are produced at room temperature by bending steel coils into the desired shape using rollers rather than heating the steel billet to high temperature, as in hot-rolled production. This provides several benefits for many projects:
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Cost-Effective: Cold-formed sheet piles are cheaper to produce than hot-rolled steel sheet piles, making them perfect for budget projects.
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Customisable: Cold-formed sheet piles can be produced in more shapes with precise dimensions and are available in many steel grades and thicknesses.
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Eco-Friendly: Lower emissions during the manufacturing process contribute to green construction.
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Standards: Cold-rolled piles are supplied according to EN 10249 and available in steel grades S235 JRC, S275 JRC, and S355 J0C.
Cold-formed sheet pile sections offer more flexibility in design and application compared to hot-rolled alternatives. Hot-rolled and cold-formedThe main difference lies in the manufacturing process, where cold-formed sections are fabricated at room temperature, allowing for precise control over shapes and dimensions. These sections are designed with a high elastic section modulus, ensuring excellent performance in bending resistance while maintaining a lightweight structure.
Hot-rolled and cold-formed steel sheet piles differ in their interlock design. Hot-rolled piles typically use the Larssen interlock, which has been used for over a hundred years and is generally stronger and more suited for specific applications requiring high watertightness.
Hot-rolled sheet pile may be better for projects requiring high load capacity, superior bending strength, or exposure to harsh environments (e.g., deep docks or heavy industrial sites). While more expensive, hot-rolled sheet piles offer higher durability and can handle more stress, making them ideal for large-scale, long-term applications.
Applications of Cold-Formed Steel Sheet Piles
Cold-formed steel sheet piles are used in both temporary and permanent structures:
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Waterfront Structures and River Embankments: Cold-rolled piles hold the banks and prevent erosion along rivers and waterways.
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Dykes and Flood Defense: With their flexibility, cold-formed piles are good in dykes and flood areas and can handle moderate water pressure and seepage.
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Temporary Cofferdams and Retaining Walls: Suitable for small retaining walls and cofferdams requiring low to moderate watertightness.
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Anchor Walls for Quay Walls: Cold-rolled piles act as reliable anchor walls for quay walls.
These applications make cold-rolled sheet piles versatile for many construction environments.
Cold-Rolled Steel Sheet Piles Types
U-Shaped Cold-Rolled Steel Sheet Piles
Used for Small to medium projects with moderate load.
U-shaped cold-rolled sheet piles are used for temporary retaining walls, flood defence and lighter applications. Their wide sections and high tensile steel make them easy to install, saving time and cost.
Advantages:
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Wider Sections: Fewer piles are required and faster installation.
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Improved Watertightness: Fewer interlocks means better resistance to seepage.
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Symmetrical Structure: Easier to align during installation.
Limitations: U-shaped piles are for light to moderate conditions and are unsuitable for large or high-pressure applications like deep foundations or major dock constructions.
Z-Shaped Cold-Rolled Steel Sheet Piles
Used for Projects that require higher load resistance, like large docks and riverbank reinforcement.
Z-shaped sheet piles have a high section modulus and continuous web, making them suitable for applications with higher bending resistance requirements. Their larger width allows for faster installation with fewer units.
Advantages:
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High Section Modulus: Higher bending strength for high-stress applications.
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Larger Widths: Fewer units are required for faster installation.
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Better Watertightness: Fewer interlocks in retaining walls make it more water-tight.
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Shear Force Transfer: Neutral axis stability is critical for Z-type sheet piles.
Limitations: While cold-formed Z-piles are strong, they may not be as strong as hot-rolled Z-piles for heavy-duty dock structures exposed to high water pressure.
Straight Cold-Rolled Steel Sheet Piles
Used for: Applications that require high horizontal tension resistance, like cofferdams.
Straight piles are known for their form and high horizontal tension resistance, making them suitable for circular cofferdams or wharfs. They have uniform thickness and are easy to handle and faster to install.
Advantages:
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High Horizontal Tension Resistance: For holding back soil or water in excavation projects.
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Easy to Install: Uniform thickness and simple design
Limitations: While suitable for horizontal loads, straight piles may not be ideal for projects that require vertical loads or high water pressure.
L-Shaped and S-Shaped (Omega) Cold-Formed Sheet Pile
Used for: Small projects with space constraints like municipal infrastructure work.
L- and S-shaped (Omega) piles are light and have single-sided interlocks, making them easy to install in confined spaces where alignment and compact design are required.
Advantages:
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Light and Compact: Suitable for small-scale applications with limited space.
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Single Side Interlocks: Simplify installation and reduce alignment issues.
Limitations: Lower load capacity is unsuitable for large or high-stress applications.
Durability and Sustainability
Cold-rolled sheet piles align with sustainability goals due to their lower emissions during manufacturing and potential for reuse in temporary structures like cofferdams. Their eco-friendly characteristics are especially relevant for projects prioritising green building standards. Additionally, corrosion-resistant coatings or galvanised finishes can be applied to extend their lifespan, reducing material wastage.
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Surface Coating: Protective paint systems can be applied to sheet piles to protect them from atmospheric and water corrosion, following EN ISO 12944 standards.
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Hot-dip galvanising: Dipping steel into molten zinc forms a corrosion-resistant zinc layer, following EN ISO 1461 standards.
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Duplex Systems: Combining galvanising with a compatible paint layer for better durability.
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Steel Grades and Section: Higher steel grades or thicker sections are used for higher corrosion zones.
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Watertightness Enhancements: For projects that require extra water tightness, bituminous fillers or welded joints on site can be applied to reduce seepage through interlocks.
Installation Techniques and Equipment
Cold-rolled steel sheet piles are designed for easy installation with standard installation methods:
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Impact Hammers: Traditional method using a big ram to drive piles vertically into the ground.
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Vibratory Hammers: Most cost-effective for granular soils, they induce vibrations to reduce soil friction.
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Hydraulic Presses: Suitable for noise-sensitive areas, especially in urban areas. Though slower, they are quieter and vibration-free
Other installation methods, such as pre-drilling and jetting, can simplify installation in difficult soils by reducing resistance. In denser layers, jetting can help in smoother installation by injecting water at the toe of the pile during driving.
Conclusion
Choosing the right cold-rolled steel sheet pile depends on your project requirements, from soil condition to load to environmental impact. For small or temporary projects, U-shape or L/S-shape piles may be suitable; for higher-stress applications, Z-shape piles may be suitable. For projects in sensitive or high-corrosion areas, corrosion protection options like surface coating and galvanisation can ensure long-term performance.
Cold-formed steel sheet piles are a sustainable and flexible solution for today’s construction, combining customisation with durability to fit your project needs. Choose the right sheet pile type, and installation will be smoother, more cost-effective, and more optimal for your construction goals.
