Applications of Large Diameter Steel Pipe

Structural Sections

The symmetry of pipe gives it the same bending strength, in any direction, which makes it an excellent product for the resistance of buckling. The stress required to buckle an axial member decreases with length. The radius of gyration has the opposite effect and increases the ability of a section to resist buckling. The W and HP sections have differnt radii of gyration (rx and ry) for the X and Y axes, while remaining constant for a pipe. The end result is that a pipe can take much higher loads for long, unsupported lengths.

Drilled Shaft Casing

Pipe casing, temporary or permanent, is often required during the construction of drilled shafts. The casing is used to hold the hole open while the reinforcement cage and concrete are installed. The ability to inspect the bottom of the hole and the elimination of any variations in the diameter of the finished drilled shaft makes for a much higher quality, finished pile. In the “Standard Guidelines for the Design and Installation of Pile Foundations” ASCE recommends a factor of safety that is 38% higher on the structural capacity of drilled shafts without casing, than those with casing.

Jacked & Bored Pipe

The placement of underground utilities is often done with jacked and bored pipe. Sections of pipe are pushed through the ground with hydraulic jacks between excavations or under a hill. The next section of pipe is then spliced onto the first and the jacking continues. Once the jacking is complete, the pipe is cleaned out to install the utilities. This allows the placement of utilities without extensive excavation which can disrupt roads, railroads, homes and businesses.

Sign Poles, Towers & Transmission Lines

Sign poles and towers are designed to resist large bending loads at the base of the structure. The availability and wide variety of thicknesses of large diameter pipe allow designers to pick the exact size needed to handle their particular project. Pipes can also be supplied in very long lengths, are simple to splice and easy to drill into hard ground. Reduction collars can facilitate the splicing of different diameters to make the design as efficient as possible.

Caissons

Caissons are most commonly used for bridge applications where it is necessary to drill into river bed material below water to found pilings or a pier foundation. Caissons are usually large diameter steel pipe, upwards of 10’ or more. Large diameter rolled and welded steel pipe provides the installation capability for these high-strength foundation systems.

Combination Walls

Large diameter pipes have high bending strengths and are often used in combination sheet pile walls. The combination of large diameter pipe piles and steel sheet piles, which is often referred to as combi-walls, pipe-z walls or king pile walls, makes a very efficient system. Like other combined walls, the king pile takes the majority of the load and the sheet pile transfers the load to the pipe and to the soil.

Steel Pipes for Construction:

HSN Code: 730511
73051119 : Galvanized pipes – Other
73051111 : Galvanized pipes – Of Iron
73051129 : Non – Galvanized pipes – Other
73051121 : Non – Galvanized pipes – Of Iron

For steel pipes used for piling for construction, the choice between galvanized or non-galvanized depends on the application and environmental conditions:

• Non-galvanized: Typically used for piling in construction, especially for deep foundation work, where corrosion resistance is less critical. Piling pipes are often driven into the ground, filled with concrete, and protected by surrounding soil or concrete, reducing exposure to corrosive elements. API 5L X65/S460, designed for high-strength pipeline applications, is commonly supplied non-galvanized for piling unless specified otherwise, as galvanization adds cost without significant benefit in such conditions.
• Galvanized: Recommended if the piling pipes are exposed to corrosive environments, such as coastal or marine settings (e.g., near Antwerp port), where saltwater or high moisture could accelerate corrosion. Galvanization (zinc coating) enhances corrosion resistance, extending service life in aggressive conditions. However, galvanizing large-diameter LSAW pipes is less common and may increase costs significantly.

Recommendation: For standard piling applications, non-galvanized pipes are sufficient and more cost-effective, especially for deep foundations where the pipe is encased or buried. If the piling is for marine or highly corrosive environments in the Netherlands, consider galvanized pipes or consult the project specifications for corrosion protection requirements. Verify with the buyer or project engineer if galvanization is mandated.