All structures rely on a solid foundation, and an in-depth understanding of what lies beneath the earth’s surface — whether it’s rock or soil — is essential. Such insight helps inform decisions on foundation types and materials that are best suited for a project.

Understanding a Structure’s Foundation Needs

A key step during a project’s inception is a site evaluation overseen by a geotechnical engineering team to consider the site’s subsurface conditions, strength characteristics and physical properties. That’s because not all foundation types are suitable for all locations. Working closely with a project’s structural engineers, the geotechnical team may recommend shallow foundations or deep foundations such as drilled shafts, micropiles, drilled piles or helical piles. Helical piles are prefabricated foundations composed of steel pipes that have welded helix-shaped plates configured along their shafts. The piles are screwed into the soil to a targeted installation torque value and design depth, where the load is then transferred from the pile to the soil along the shaft and through the helical plates.

Compared to concrete drilled shaft foundations, helical piles offer several advantages, including:

  • Better quality control.
  • Reduced labor demands.
  • Compact installation equipment.
  • Verification of axial capacity using a torque-to-capacity relationship.
  • Faster installation.
  • Fewer environmental risks. 

Helical piles are a solid choice, especially if a geotechnical evaluation reveals the project site contains loose or soft soils, groundwater or other conditions less favorable for an excavated foundation such as a concrete drilled shaft. Because the piles are screwed into the ground, there is no need to maintain a stable excavation through soils that can be prone to collapse. The piles are versatile, can be installed in any climate and used on any size project. The diameter and length of the pile can also be changed, depending on load requirements.

Along with identifying favorable soil conditions for using helical piles, a geotechnical engineering team will also identify potential risks when considering helical piles. Cobbles, boulders and shallow bedrock can pose challenges when installing the piles and an alternative foundation choice may be recommended.

Benefits of In-House Engineering Services

While some companies outsource a project’s geotechnical requirements, having a geotechnical engineering team in-house has numerous benefits, including the ability to communicate and respond quickly should any foundation design changes become necessary. Those changes would not need to go through a subcontractor. Also, familiarity with tools and equipment available for each project allows the geotechnical engineering team to identify issues during the design phase that otherwise could delay the project. An in-house team will also be familiar with the project team’s workflow.

There are many layers throughout a construction project, but a solid foundation starts with the investigation, analysis and recommendations provided by the geotechnical engineering team. And having the services of a geotechnical team in-house will benefit a project of any size.


Helical piles offer several advantages over traditional concrete drilled shaft foundations. Read about why helical piles can deliver precisely what you need.

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Bradley Gardner joined Burns & McDonnell in 2001 and has extensive experience as a geotechnical engineer supporting the subsurface investigation, foundation design and construction observation phases of projects. The Burns & McDonnell geotechnical engineering team supports all of the firm’s industries across all Burns & McDonnell offices.