Which Is Better? Round vs. Square Shaft for Helical Pile Design

Which Is Better? Round vs. Square Shaft for Helical Pile Design

When engineering the ideal helical pile design for your foundational application, there are many important factors to consider. One of them is shape. Here’s some insight on round vs. square helical pile shafts, so you can decide which might option be best suited for your project.

Round vs. Square Helical Pile Shaft

There are two main helical pile shaft designs: round and square. Neither shape is overwhelmingly “better” than the other — it just depends on your project’s conditions and goals.

Below, we’ll list each type of helical pile design, along with its typical sizes, advantages, disadvantages, and applications.

Round-Shaft Helical Piles

Round-shaft helical piles are made of steel tubes with a circular, hollow cross-sections. They’re typically wider in diameter than most square-shaft piles. This makes round-shaft helical piles the best type of helical pile shaft for resisting lateral loads.

You can see the round shape of these helical piles from one of our recent projects:

Trace CP3

Sizes

Typical sizes for round-shaft helical piles are: 2.875”, 3.5”, 4.5”, 6”, 8”, and 10”+.

Advantages

Round-shaft helical piles bring the following advantages:

  • Ideal for soft soils
  • Able to support large lateral loads
  • Higher installation torque rating
  • Can be filled with grout for boosted structural durability

Disadvantages

Because round-shaft helical piles generally have larger diameters than square-shaft piles, they can be more difficult to insert and stabilize in very dense or rocky soils.

Suggested Applications

Round-shaft helical piles are most frequently utilized in new construction settings where high lateral loading and/or buckling are concerns.

Square-Shaft Helical Piles

Square-shaft helical piles are solid, square bars made of steel. They’re commonly smaller in diameter than round-shaft helical piles, but can still deliver a great capacity-to-torque ratio. Plus, they offer more stability and ease of installation in certain environmental conditions.

You can see the square shaft of these helical piles from one of our recent projects:

Goodrich Barremore

Sizes

Typical sizes for square-shaft helical piles are: 1.5”, 1.75”, 2”, and 2.25”.

Advantages

Square-shaft helical piles have their own set of advantages, including:

  • Ideal for very hard, dense, or rocky soils
  • Better at penetrating without causing ground damage
  • Able to support large axial compressive loads

Disadvantages

Square-shaft helical piles don’t have as much lateral capacity and can’t defend as much against buckling.

Suggested Applications

Due to their unique capabilities and shortcomings, square-shaft helical piles are ideal for projects with rocky or firm soil conditions. They should be avoided in situations where high lateral loading or buckling resistance is necessary.

Combo Helical Piles

In some cases, a combo pile is best. A combo pile is a combination of a round-shaft and a square-shaft pile. It has a square-shaft lead that is followed by a series of round-shaft extensions.

Sizes

Typical sizes for combo helical piles are: 1.5”/2.875”, 1.75”/3.5”, 2.25”/4.5”.

Advantages

Combo helical piles offer the “best of both worlds” when it comes to installation and performance. Here are some of their advantages:

  • Great penetrating characteristics of square-shaft piles
  • Suitable for very dense or rocky soil conditions
  • Large-diameter round shaft extension
  • Bucking resistance
  • Able to support high lateral loads

Disadvantages

Now you might be wondering, “Why wouldn’t I just always use a combo pile?” Well, it’s not always necessary and it’s always more expensive. The extra material costs make combo piles less affordable, so it’s best to only use them when they’re absolutely needed.

Suggested Applications

Combo helical piles are most often used in compression applications. This is when layers of hard soil are buried deep under softer surface soil. Think of environments like high water tables, grout-restricted sites, etc.

For Helical Pile Design & Installation Done Right, Contact Elite Helical.

To get the most out of your helical pile installation, you need to make sure you’re working with the helical pile design that best suits your application’s needs.

Need help making the right choice? Contact our experts at Elite Helical. We’ll walk you through various options, then help you install a foundational system that will last for years.

How Long Do Helical Piles Last?

How Long Do Helical Piles Last?

You may have heard that helical piles are some of the strongest, most durable foundational solutions on the market. But how long do they actually last? Find out below. 

How Long Do Helical Piles Last? The Breakdown

Generally speaking, helical piles can last 100 years or more. Most contractors estimate a lifespan of around 150 years, but some helical piles have even lasted 300+ years. 

Needless to say, these are some of the longest-lasting tools in the industry. Their great longevity makes a case for them being the most cost-effective and environmentally friendly solutions on the market as well. With fewer repairs and replacements necessary over the years, you won’t have to worry about putting too much time and money in besides the upfront installation investment. 

Factors That Influence Helical Pile Lifespan

Not all helical piles last the same amount of time. Some fail faster than others, and some live to see their 350th “birthday.” How? There are a number of factors that affect helical pile longevity — most of which are environmental and have nothing to do with the helical pile itself. 

Helical Pile Material

Most helical piles are composed of rust-resistant galvanized steel. This is a strong, durable material that will help them perform for centuries. However, if you were to use a different type of material, that performance may suffer or improve even more. 

Load-Bearing Capacity Calculation

Some great benefits of helical piles is that they offer instant load-bearing capacities and that they can support structures of all shapes, sizes, and weights. If you design and space accordingly, they can accommodate hundreds of tons or more. 

However, if you were to get your load-bearing capacity calculations wrong and mistakenly apply too high of a load to the pile system, its endurance could falter. 

Soil Conditions

Helical piles may not last as long in areas with poor, volatile soil conditions. Anything highly acidic, rocky, or eroding could expose the piles to more wear and tear. 

On the flipside, helical piles placed in environments with very stable soil conditions could last much longer than the typical 150-year lifespan. 

Location

Similarly, various regions lend themselves to significant ground movement — which could definitely affect the lifespan of your helical piles. Think of locations like coastal areas, mountainous areas, and places with fault lines. The soil movement in these environments could break your helical piles down much faster than stable soil would.

Helical Pile Life Expectancy vs. Other Foundational Solutions

Let’s take a look at how helical pile life expectancy stacks up against other foundational solutions. You might be shocked! 

Here’s a chart with estimates for how long each choice can last. Please keep in mind that these are estimates and do not take the influencing factors listed above into account. 

Foundation Material

Estimated Lifespan

Helical Piles

150 years

Stone

100 years

Slab Concrete

80 years

ICF Blocks

75 years

Wood

25 years

Ready to Get Your Helical Pile Project Started? Contact Us.

For safer, sounder solutions you can only trust the best. Elite Helical is your top choice for turnkey helical pile solutions that will last a lifetime — or longer! Get in touch with our experts to learn more about how we can support your next project.