The Drivecast™ Displacement Pile is Revolutionizing Deep Foundation Systems

by Matt Conte

Conte Company helped create the Hubbell-Chance displacement pile product known as Drivecast™.

If you haven’t considered grout displacement piles for your project, you really should. There are many benefits to using such a system and more testing and performance data is produced each-and-every day. Here’s a little background on the product and how it performs, which explains why we’re so excited to tell you about it.

This patented grouted displacement pile was designed to be used in high side friction and end bearing applications. This combination of load carrying capacity allows the pile to be used in most soil conditions and load requirements. The added rigidity and larger grout shaft resist buckling and high lateral loads, where segmental piles systems wouldn’t normally be considered. Since each coupling joint is completely encased in grout, the finish pile acts as one solid piece in the soil.

During early Spring of 2018, Conte Company performed a load testing program that compared Drivecast piles to traditional driven and helical piles. (8) different piles were installed within the same site, to a similar depth. These piles were all tested in compression and lateral resistance. We even used a tell-tale testing method on one of the Drivecast piles—which is a method for isolating the side friction from the end bearing resistance of a pile. The results were extremely interesting and educational.

  • The (3) different Drivecast size piles outperformed the (3) driven piles and (2) helical piles in compression
  • Two of the Drivecast piles were laterally tested during a week of torrential rainstorms and they still held respectable numbers
  • The RS4500DC pile achieved the largest of the group at over 20 kips

With the help of GZA GeoEnvironmental, Inc., the results of all the testing were cataloged and evaluated. You can download the full report here. We would like to extend our deepest gratitude to King Industries, Inc. for offering the use of their property for the testing location. We would also like to give a special thanks to Gary and Charlie Wetmore at G&C Marine for bringing out their new blow hammer to help with the driven pile installation!

If you’d like to learn more about Drivecast

Send us a message give us a call at (203) 853-2400. We’re happy to tell you all about it.

You can also watch our promo video here:

4 Types of Helical Pile Design: Advantages & Disadvantages

by Matt Conte

Every commercial construction project is unique. Each type of structure will require a foundation specifically engineered to account for the size of the job and the ground on which it’s built. For the same reason, helical pile designs span a variety of shapes and sizes to accommodate a wide range of applications and variables such as soil type, soil profile depths, pile loading type, pile capacity requirements, the type of structure to be supported, etc. There are dozens of sizes, shaft type, and helix configurations available to make sure the proper helical pile is used for the job.

When engineered correctly, a deep foundation anchored with the correct helical pile design will last for many years. Choosing an improper helical pile design can lead to devastating results.

Make sure you choose the proper pile configuration… Call Conte Company Today!

In this brief guide, we’ve outlined the 4 major categories of helical pile designs, including their typical implementations, advantages and disadvantages of each.

Solid Square Shaft

The square shaft is typically solid and capable of large axial compressive loads. The solid shaft is continuous at each extension and carries the load down through to the end of the pile. Square shaft extensions can also used in a variety of tension applications.

Typical Sizes: 1.5”, 1.75”, 2”, 2.25”

Advantages: In rocky and hard soils, square shaft leads are better at advancing without damage.

Disadvantages: Slender shafts do not resist lateral loads well and buckling can occur in soft soils due to the narrower width.

Round Shaft Pipe

The round shaft pipe helical pile provides a much wider diameter than most square shaft piles. The wider cross section provides better structural capacity where large moments, lateral loading, or buckling can be present.

Typical Sizes: 2.875”, 3.5”, 4.5”, 6”, 8”, 10″+

Advantages: Round shaft piles are ideal for softer soils and when there is potential for high lateral loads. The pipe shafts can be grout filled for added structural capacity.

Disadvantages: Larger shafts can be more difficult to penetrate very dense or rocky soils.

Square & Round Shaft Combo Pile

Typically a combo pile has a square shaft lead, followed by round shaft extensions. These types of helical piles are used primarily in compression applications where layers of hard soil are located deep under a softer surface soil. Square/round combo piles are often chosen for high water tables, grout restricted sites or for sites with soils that make them a more economic choice than a grouted pile configuration.

Typical Sizes: 1.5”/2.875”, 1.75”/3.5”, 2.25”/4.5″

Advantages: This combines the better penetrating characteristics of the square shaft with the large diameter round shaft extension to resist buckling and lateral loading.

Disadvantages: Extra material costs can make combo pile solutions a less economical solution than alternative helical piers. It is only necessary under specific circumstances.

Grouted Square Shaft

All square shaft piles can be fitted with accessories to add a grouted casing. This casing is typically 5” to 8” in diameter and can be cased in PVC or steel pipe, or just grout. The grout also creates skin friction with the soil that can help the compression and tension capacity of the pile. The larger cross section improves lateral capacities, bending moment, and buckling resistance strength when compared to the slender square shaft pile on its own.

Advantages: In some soil conditions, square shafts with grout casing are more economical than larger diameter round shaft pipe piles.

Disadvantages: In some cases, grout plates can have difficulty advancing into very dense or rocky soils. Grout may also be prohibited from certain projects, for example in wetland applications or a site which cannot properly accommodate grout-mixing on site.

Choosing the right type of helical pile design needs to be done by an expert!

These basic explanations offer guidelines for which types of helical piles are appropriate for various projects, but there are many variables that go into making an educated decision.

Contact us for a free consultation about your upcoming project

Why Helical Piles?

by Matt Conte

During these modern times of engineering and construction, there are many different ways to do just about anything. This includes the selection of a helical pile foundation. Pile foundations have been used for years to support structures that bear on unsuitable soils. As equipment and methods progressed, so did the applications and installation of each type of pile. All of these options still exist because each site and project requirement is different. We have to weigh our options to decide what the safest, most cost effective approach to providing a pile foundation is going to be.

Helical Piles have been around for many years, even though most people still haven’t heard of them. They are screwed into the soil using a motorized auger torque driver, which is attached to a piece of construction equipment. The screwing method eliminates the need for vibration and aggressive impact to advance the pile into the soil. The Helical Pile simply screws into the ground. With the torque motor creating the force needed to install the pile, relatively small equipment can be used for helical pile installation.

The benefits of using small equipment can change the project in many ways. Some projects would otherwise be impossible, if not for the use of small equipment. Going inside buildings, basements, through landscaping, beneath lifted houses, high voltage, tight locations, etc. are all possible because helical piles require such small equipment to install. The reduced vibration and noise allow for businesses and daily activities to continue during installation, and the low emissions of smaller equipment help minimize any environmental impacts. Some older structures are so unstable, that any vibration will compromise their state. Helical piles can be used to underpin these structures without harming the current conditions.