The 4 Most Used Deep Foundation Types

In large-scale and industrial construction projects, choosing the right foundation is critical to ensuring structural integrity, safety, and longevity. Among these, deep foundations are commonly used when the upper layers of soil are not strong enough to support the structure. Unlike shallow foundations, which rely on surface-level soil, deep foundations transfer the load deeper into the ground, where soil or rock layers are more stable.

This article explores the four most widely used deep foundation types, analyzing their effectiveness based on factors like soil conditions, load-bearing requirements, environmental constraints, installation processes, cost-efficiency, and long-term performance.

TL;DR — 4 Deep Foundation Types

1. Helical Piles

Helical piles, also known as screw piles, are a highly versatile deep foundation option used in industrial construction projects, especially in soft or unstable soil conditions. These piles consist of steel shafts with helical (screw-shaped) plates attached, which are driven into the ground using hydraulic motors.

Key Benefits

• Ease of Installation: Helical piles can be installed quickly with minimal vibration, making them a suitable choice in urban areas or projects close to existing structures.
• Cost-efficiency: The speed and simplicity of installation, along with the minimal excavation required, contribute to reduced costs.
• Load-bearing Capability: Helical piles can handle both compression and tension loads, making them suitable for a range of applications, from foundations to retaining walls.
• Environmental Impact: With minimal disturbance to the surrounding soil and no need for concrete curing, helical piles are an environmentally friendly solution.

Best Used For

• Ideal for projects where soil conditions are weak or inconsistent.
• Used extensively in areas with limited access or environmentally sensitive regions, such as wetlands.
• Suitable for industrial applications requiring deep support, such as pipelines, bridges, and communication towers.

Long-term Performance

Helical piles offer long-term durability, as they resist corrosion with proper coatings and can be easily monitored and adjusted over time if necessary. Their adaptability to changing ground conditions makes them a reliable long-term option.

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2. Drilled Shafts (Caissons)

Drilled shafts, also known as caissons, involve drilling a deep hole into the ground and filling it with reinforced concrete. They are one of the most effective solutions for transferring large structural loads to deeper, more stable layers of soil or rock.

Key Benefits

• Load-bearing Capacity: Drilled shafts can be designed to handle extremely heavy loads, making them suitable for industrial facilities and skyscrapers.
• Versatility: Can be customized in terms of diameter and depth based on the specific load-bearing requirements of the project.
• Suitability for Rocky Terrain: Drilled shafts can be installed in hard soil or rock, where other deep foundation types might struggle.

Best Used For

• Best suited for high-load projects, such as bridges, large buildings, and dams.
• Works well in stable soil conditions where lateral forces, such as wind or seismic activity, need to be resisted.
• Ideal for projects requiring foundations that can handle substantial compression loads.

Long-term Performance

Drilled shafts provide exceptional durability and strength. When properly designed and installed, they offer excellent long-term performance with minimal maintenance.

Installation Considerations

Drilled shaft installation requires heavy machinery and precise engineering. The process involves drilling, casing the hole, and pouring concrete, which can be time-consuming and costly compared to other methods.

3. Driven Piles

Driven piles are long, slender columns, usually made of steel, concrete, or timber, that are driven into the ground using a pile driver. These piles displace the soil around them as they penetrate, creating friction that helps support the structure.

Key Benefits

• Cost-effective for Large Projects: Due to their relatively fast installation process, driven piles are a cost-effective choice for large projects.
• Load Distribution: Driven piles distribute the load through both end-bearing (to the bedrock) and friction along the pile shaft, providing solid support.
• Wide Range of Materials: Driven piles can be made from concrete, steel, or timber, allowing flexibility depending on the project’s needs.

Best Used For

• Suitable for coastal and waterfront projects where the foundation needs to be installed below the water table.
• Effective in areas with sandy or loose soils where other foundation types may struggle.
• Commonly used for bridge abutments, industrial plants, and offshore platforms.

Long-term Performance

Driven piles offer excellent long-term stability, especially in areas where they can reach a solid bedrock layer. Their resilience to environmental factors like erosion or corrosion (if made from treated materials) enhances their durability.

Installation Considerations

One of the main drawbacks is the significant vibration and noise caused during installation, which may not be suitable for projects near residential areas or sensitive equipment. Additionally, the displacement of soil can cause issues in densely built environments.

4. Micropiles

Micropiles are small-diameter, high-capacity drilled piles used for foundations where space is restricted or where ground conditions are challenging. They are often used in retrofit projects, where adding additional foundation support is required.

Key Benefits

• Minimal Disruption: Due to their small size, micropiles can be installed in tight spaces with minimal disruption to the surrounding environment.
• Versatility: Micropiles can be used in a wide variety of ground conditions, from soft soils to hard rock, making them a flexible solution for difficult sites.
• High Load Capacity: Despite their small diameter, micropiles can bear significant loads, providing reliable support for a wide range of structures.

Best Used For

• Suitable for projects in restricted spaces, such as urban redevelopment or sites with existing infrastructure.
• Effective in locations where ground conditions are unstable or contain obstructions like underground utilities or boulders.
• Ideal for retrofitting and upgrading foundations in existing structures.

Long-term Performance

Micropiles are highly durable and perform well over the long term, especially when used to reinforce or retrofit existing structures. Their ability to withstand lateral and seismic forces enhances their resilience.

Installation Considerations

Micropiles require specialized equipment for drilling and installation, which can increase upfront costs. However, their minimal footprint and adaptability typically offset these initial expenses.

Experience the Benefits of Helical Piles for Yourself

Choosing the right deep foundation type for a construction project depends on multiple factors, but helical piles often stand out for their versatility, ease of installation, and environmentally friendly nature, making them a popular choice in both industrial and urban projects.

If you need a deep foundation solution and think helical piles might be your answer, contact our team. With over 50 years of combined industry experience, we’re here to be a turnkey resource — from design aid, to supply, installation, and beyond.