Deep Foundations, Part Four: Type Comparisons

Construction Cost Comparison Between Auger Cast Pile and Drilled Shaft

The economic evaluation of auger cast piles and drilled shaft piles involves considering several factors that can affect the overall cost of the foundation system. Here are some key aspects to consider when comparing the economic aspects of these two pile types:

Construction Method

Auger cast piles are typically installed faster compared to drilled shaft piles. The continuous flight auger used in auger cast pile construction allows for quick installation, reducing labor and equipment costs. On the other hand, drilled shaft piles require more time and specialized equipment for drilling and reinforcement placement.

Equipment and Material Costs

The equipment required for auger cast pile installation is generally less expensive compared to the specialized drilling rigs used for drilled shaft piles. Auger cast piles also normally do not require steel reinforcement, reducing material costs. In contrast, drilled shaft piles require steel reinforcement cages, which can add to the overall material expenses.

Site Conditions

The suitability of each pile type depends on the site’s soil conditions. Auger cast piles are generally more suitable for cohesive soils, while drilled shaft piles can be used in a wider range of soil conditions, including both cohesive and non-cohesive soils. The site-specific soil conditions can impact the cost of implementing each pile type.

Load-Bearing Capacity

Drilled shaft piles are often preferred for projects requiring higher load-bearing capacity. The inclusion of steel reinforcement in drilled shaft piles provides additional strength and allows them to support heavier loads. Auger cast piles, being primarily friction-based piles, may have limitations in terms of their load-bearing capacity.

Project Scale and Design Requirements

The scale and complexity of the project influences the choice between auger cast piles and drilled shaft piles. For larger and more structurally demanding projects, where higher load-bearing capacity and flexibility in design are essential, drilled shaft piles may be more suitable, albeit at potentially higher costs.

Ultimately, conducting a detailed cost analysis that considers the specific project requirements, soil conditions, construction timelines, equipment and material costs, and other factors will provide a more accurate evaluation of the economic feasibility of selecting piles. Engaging the expertise of geotechnical engineers and cost estimators is crucial to make an informed decision based on the specific project parameters and budgetary constraints.

Ready to learn more?

Deep Foundations, Part One: Intro

Deep Foundations, Part Two: Comparison with Shallow Foundations

Deep Foundations, Part Three: Types

Different Structural Foundation Types

Straight Shaft Drilled Concrete Pier Foundation

Series References:

Structure Magazine
National Highway Institute


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