Pile casing

Types of Pile Casings

Before discussing the types pile casings, it is good to understand what casing pipes are. Casing pipes are structural steel tubes that strengthen and support the sides of a drilled flued or borehole to keep it from collapsing. They are also used to obtain samples of soil or rock and, later, to provide a conduit through which to inject or extract fluids.

Typically, there are three main types of pile casings: steel, concrete, and composite pile casings.

• Steel Pile Casings

  Steel casings provide robust and durable solutions for various applications, and this is because steel is naturally strong and has the ability to withstand heavy loads and pressures. Also, it is very flexible, making it easy to adapt to different site conditions. When it comes to applying pile casings, structural integrity is a major requirement. Steel pile casings meet this requirement, ensuring that the piles can support the structure's load throughout its lifespan. Steel has superior corrosion resistance when galvanized or coated. This makes the pile casing last longer and reduces life cycle costs. Steel piles are easy to fabricate and customize to meet different specifications such as lengths, diameters, wall thicknesses, and design requirements.

• Concrete Pile Casings

  Concrete casings work better for projects with lower corrosion risks and where cost efficiency is prioritized. In concrete pile casings, concrete is inherently strong. It enables the shells of the piles to be thinner with higher load-bearing capacity. Unlike steel, concrete offers natural fire resistance. Because of this, concrete pile casings are a good option for projects in areas with stringent fire regulations. Concrete requires minimal maintenance after installation. This makes it a more economical option over the pile's lifespan. Using locally sourced materials for concrete can lower project costs. Since concrete has low weight-to-volume ratio, it reduces transportation costs and site handling. Also, unprotected concrete has low corrosion resistance, thus making it suitable for applications with a low risk of corrosion.

• Composite Pile Casings

  Composite casings have a superior performance for projects that require durability and corrosion resistance. Composite materials combine the advantages of steel and concrete. This results in a higher strength-to-weight ratio, lower overall costs, and highly durable piles. Also, composite materials are naturally non-corrosive. Therefore, they offer excellent longevity in corrosive environments. The ability to tailor composite materials leads to better pile performance in site-specific conditions. These include factors like corrosion resistance, load capacity, and weight. Pile installation for composite materials is easier and quicker. This is due to their lightweight and high flexibility. The end result is reduced project costs, including labor, equipment, and time.

Functions & Features of Pile Casing

Applications of pile casings can be seen in sectors ranging from construction through marine work all the way up to geothermal energy production; basically anywhere that needs deep foundations or boreholes into soil/rock has become part of this global market which is evolving rapidly due to new technologies such as subsea robotics being used for inspection/testing purposes alongside traditional methods like coring/sampling etc.

• Building Deep Foundations: Pile casings help create strong piles that go deep into the ground to support heavy buildings and bridges.
• Bridges & Structures Support: They ensure bridge piles are sturdy and well-anchored, allowing safe spans over water or valleys.
• Marine Structures Engineering: Pile casings allow the build-up of strong supports like docks, piers, and wind turbine bases that can endure any beating from harsh marine conditions.
• Soil Protection: The casing protects the surrounding soil while piles are being built, stopping erosion or soil damage in sensitive areas.
• Foundation Strength Boost: They make foundations stronger by spreading out loads, which prevents settling or shifting that could harm structures.
• Drill Depth Control: With pile casings, the exact drilling depth needed for different site conditions can be reached, ensuring well-built foundations.
• Easy Soil Sampling: They make it easy to take soil samples during drilling to check its type and behavior, which helps design strong foundations based on actual site conditions.
• Ensures Pile Straightness: The casing keeps piles straight and centered while being installed, which is important for their strength and stability.

Casing piles have several features necessary for effectively performing these functions, including

• Diameter Variety: Casing piles come in different sizes so they can be adapted to project requirements, site conditions, and load capacities.
• Wall Thickness Options: The thickness of the walls also varies. This ensures that different levels of strength, durability, and resistance to deformation under loads can be provided.
• Corrosion Resistance: Marine pile casings are often made with coatings that resist rusting or use stainless steel. This extends their life in corrosive environments.
• Connection Types: Piles may join through welded, threaded or spigot-and-socket connections to allow easy length adjustments and secure integration on-site between sections.
• Modular Design: Many types have a modular design which allows them to be customized and adapted for various applications, ensuring versatility and flexibility.

Casing piles are pivotal in infrastructure and construction, especially in areas requiring deep foundations and the ability to withstand various loads and environmental conditions.

Uses of pile casing

The construction industry is the primary user of pile casings, which, among other things, helps in:

• Soil Preservation: In geotechnical engineering, pile casing is used to encase piles that are driven into the ground to support buildings and other structures. Pile casings aid in maintaining the integrity of the soil around the pile, safeguarding the pile from damage, and enhancing the pile's load-bearing capacity.
• Corrosion Resistance: In the oil and gas industry, jute pile casings are used to protect pipeline casings. Pipeline casings protect against corrosion, damage, or leakage, extending the life of the pipeline and ensuring the safe and efficient transport of oil and gas products.
• Stabilizing Soils: Casing piles are used in civil engineering to stabilize soils. Casing piles are large-diameter concrete piles that are drilled-in and cased, providing a stable foundation for structures built on unstable soils. The use of casing piles helps mitigate risks associated with settling, shifting, or collapsing of structures, ensuring safety and integrity of buildings.
• Creating Barrier Walls: In environmental remediation, pile casings are used to create barrier walls. The pile casings are used to construct barrier walls or containment structures that isolate contaminated areas and prevent further spread of hazardous materials. This helps in successfully containing and remediating polluted areas, safeguarding public health and the environment.
• Fire Prevention: Casing, in this case, acts as a fire-retardant cover for various structures. Steel or concrete casings are used to encase structural members such as beams and columns to protect against fire. These fire-resistance casings provide vital protection to structural components in the event of a fire, maintaining their integrity and load-bearing capacity.
• Ballot and Tabulation Centers: Pile casings aka ballot boxes are used in elections and referendums for secure collection and storage of votes. They provide a secure and tamper-proof method of collecting and storing votes, ensuring integrity and confidentiality of the voting process.

The above list shows that casings serve a broad range of applications across various industries, providing protection, support, and functionality in diverse environments. These applications help to safeguard structures, mitigate risks, and enhance the overall performance of various systems.

How to Choose a Pile Casing

Choosing the right casing for the piles is an important decision that contractors need to make carefully, depending on the specific project requirements. Here are some factors that will help with the selection process:

• Soil Condition: Pile casings come in different sizes, and the first thing to do when selecting a casing is to understand the type of soil at the construction site. The soil condition will help with selecting the right diameter and thickness for the pile case. For instance, strong and hard soils will require thicker and stronger cases to avoid breaking while soft and weak soils can work with pile cases with normal strength and thickness.
• Load Requirement: Find out the total weight and structure load that the piles have to support. The load requirement will help inform the selection decision for the appropriate wall thickness and strength to meet the loading requirements.
• Environment: Consider the environmental factors and the conditions surrounding the construction site. Elements like moisture, chemicals in the soil, and temperature can affect the quality and durability of the pile casing. If the site has high corrosion factors, the case should be insulated with a pile cap coating for cases with high-stack pile caps.
• Installation Method: The installation method at the construction site will influence the selection decision. Some methods require pile cases with smooth interiors for easy driving through the soil, while others may need interlocking features for added stability during placement.
• Budget: Budget is an important factor to consider in every selection process. The cost of the pile casing and the total cost of the site preparation and installation method should be calculated to arrive at a total budget.
• Refurbishment: Pile casings are available in different types, such as concrete and steel. The type selected will influence the need for regular maintenance and refurbishment. For example, steel cases need regular maintenance to avoid rusting, while concrete cases don't rust and require less maintenance over time.

Pile casing FAQs

Q1: Why is water treated before using it for piling?

A1: Water is treated to reduce the concentration of chlorides and sulfates in the pile casing. This helps to protect the pile from early corrosion. Water with high chloride concentration can cause steel piles to rust quickly.

Q2: Why do piles need to be covered with casings?

A2: Casings protect piles from getting damaged before they are put in the ground. They also keep the concrete inside the pile safe so it can cure properly. The casing shields the concrete from air and moisture until the pile is installed. This ensures the pile can support the structure as intended.

Q3: How are piles inspected after construction?

A3: There is a visual inspection after the casings are removed to check the pile surface. After that, ultrasound testing can be done. The testing checks the concrete quality and confirms there are no cracks or defects. This makes sure the pile is built correctly.