The technique of driving pile foundations into the earth close to a building that is being built is called piling. The loads are transferred from the structure to the ground using these piles. Pile foundations are crucial when the soil is too weak to support heavy loads from the structure.
What is a Pipe Pile?
Pipe piles are hollow helical-welded or welded steel pipes designed for deep-foundation applications. By using both skin friction and point bearing to withstand pressure, they move loads from buildings and other structures to deep, stable soil layers.
Pipe piles come in both closed-ended and open-ended designs, and they can be pushed into place using plates or points. In some circumstances, pipe piles are filled with concrete to increase their robustness and support the weight of the building above them. In some situations, filling smaller, thinner piles with concrete may not always be more economical than employing larger, thicker pipe piles.
Common Sizes
Pile pipes are available in a variety of sizes to support the heavy loads of the structures from 50 to 500 kips. Most options are available in diameters of 18” to 28”(18 inches to 28 inches). Pipe piles can also be connected to form structures hundreds of feet long.
Types of Pipe Piling
Some important types of pipe piling with unique properties and applications are as follows:
- Open-Ended Unplugged Pile: This pile is open at both ends, allowing water to enter and form a hydraulic lock, which adds stability. It works well on soft or watery soils.
- Open-Ended Plugged Pile: Similar to an unplugged pile, but with a cover at the top to keep water out, making it more stable in moisture-sensitive soils.
- Bottom Plate Steel Pipe: This pile has a flat plate at the bottom for greater bearing capacity and is ideal for constructions that require substantial support, such as high-rise structures.
- Steel Pipe with Rock Shoe: A steel shoe with rock at the bottom adds stability in loose or soft soils.
- Franki Pipe Piles: Franki pipe piles are permanent piles loaded with wet concrete that can withstand higher driving impacts than other varieties.
Application of Pipe Pile
Pipe piles are typically used for:
- Construction, bridge, and highway foundations
- Foundations for marine constructions, docks, and offshore projects.
- Railway and oilfield construction foundations
- Foundations of communication towers and columns
These are just a few scenarios in which pipe piles can be used. They are best suited for large, massive buildings as well as regions with weak soil or shallow depths that require deep driving for stability. Pipe piles are ideal for marine applications that require extra support at the base on the ocean or canal floor.
Advantages of Pipe Pile
Steel pipe piles offer several key benefits for construction projects, including:
- They are strong and resilient, ideal for structures that need to handle heavy loads and tough conditions.
- Their adaptable design suits a variety of construction applications and can be customised for specific project needs.
- Steel pipe piles resist corrosion, making them suitable for constructing heavy structures that bear heavy loads.
- They can also withstand harsh environments and rough weather conditions.
- Although their price seems high initially, their durability makes them a long-term, budget-friendly choice.
- Steel piles can pierce through hard layers and boulders.
- The amount of soil moved by the piling operation is small.
Disadvantages of Pipe Pile
- Rust and Electrolysis:
Steel may weaken (rust) when exposed to moisture, soil chemicals, or extreme temperatures. Electrical currents in the soil, known as electrolysis, can potentially cause damage to steel piles. These effects gradually weaken the steel, diminishing its rigidity and longevity.
- Price:
Steel piles are typically costly, particularly if they are not driven deep enough to reach a solid, load-bearing layer of soil or rock capable of supporting heavy loads. If a strong layer is not available at a sufficient depth, the additional material and installation costs may make steel piles less cost-effective.
- Comparison to Friction Pipes:
Steel piles are primarily designed to support loads at the pile’s end. Friction piles, on the other hand, are more successful when weights can be dispersed evenly across the pile’s surface area due to friction with the surrounding soil. Friction piles are better suited to particular soil conditions than steel piles.
How to Interlock Pipe Piles?
Interlocking pipe piles are formed by joining pipes with a “ball-and-socket” mechanical connector welded along their full length to make a continuous, waterproof wall. These piles can be used temporarily or permanently. They are typically used for:
- Supporting open excavations.
- Groundwater flow barriers.
- Flood control in low-lying locations.
- Cofferdams and Dry Docks
- Unlike other methods such as sheet piling, interlocking pipe piles can be constructed in bouldery terrain.
A pile guide is utilised to ensure vertical installation, and the piles are installed using rotary percussion drilling techniques with an air or water flush, as well as a down-the-hole hammer to deal with obstacles.
The pile assembly is manufactured off-site for quick installation and may be easily embedded in solid rock. Grouting inside the pipe and around the pile is completed.
Installation Process of Pipe Pile
To install a steel pipe pile, use a pile driver to force it into the earth. This technique requires careful planning to ensure that it is appropriately positioned and capable of supporting the necessary weight.
Before driving the pile, the soil conditions and load requirements must be assessed to determine the appropriate length and diameter. The soil should be robust enough to withstand vertical and lateral stresses.
The pile driver subsequently drives the pile into the earth to the specified depth. Once in position, the surrounding soil is compacted to provide extra stability.
Conclusion
A deep foundation is required for structures that will withstand enormous loads. Steel pipe piles are extremely versatile and may be customised to specific load needs, which helps to cut costs. They are less expensive, easier to install, and can be safely examined and tested before use. Furthermore, they are simple to add to after construction and have inexpensive replacement costs because they do not crack during installation.
FAQ’s
Pipe piles are hollow helical-welded or welded steel pipes designed for deep-down foundation applications. By using both skin friction and point bearing to withstand pressure, they transfer loads from buildings and other structures to deep, stable soil layers.
Steel pipes are drilled or driven into the earth to form a pipe pile. They are normally driven using a large impact hammer.
Steel pipes used for piling range in wall thickness from 0.109″ to 2.500″ (2.8 to 63.5 mm), with diameters ranging from 8″ (203.2 mm) to 48″ (1219 mm). Common pipe pile sizes can withstand loads ranging from 60 kips (267 kN) to over 400 kips (1779 kN).
Pipe piles are usually filled with concrete, but in some cases, they are left empty to reduce costs. If not filled with concrete, a corrosion protection layer should be applied.