Understanding Helical Piers: A Comprehensive Guide

In the world of foundation repair and construction, helical piers play a crucial role in stabilizing structures and ensuring their longevity. This blog post aims to provide a comprehensive overview of helical piers, including their installation process, applications, and the benefits of using foam injection for soil stabilization.

What are Helical Piers?

Helical piers, also known as helical piles, are deep foundation systems used to support structures by transferring their load to deeper, more stable soil layers. They consist of a shaft with helical plates that are screwed into the ground, providing resistance against vertical loads.

The Installation Process

Initial Assessment

Before installation, it is essential to assess the site conditions. Engineers typically evaluate soil data to determine the appropriate depth and torque requirements for the helical piers.

Equipment and Crew

The installation of helical piers requires specialized equipment, including mini excavators and torque heads. A typical crew consists of two to three members, allowing for efficient installation. Each crew can install about four piers per day, depending on site conditions.

Digging and Preparation

The installation begins with digging a small hole (approximately 2x3 feet) at each pier location. This allows access for the helical pier installation equipment. The crew then prepares the site by ensuring that the soil is compacted and stable.

Installing the Helical Piers

Once the site is prepared, the helical piers are installed using a torque head attached to the shaft. The torque head measures the amount of torque required to screw the pier into the ground, which is crucial for ensuring that the pier meets the load requirements specified by the engineer. The installation process involves:

• Screwing the pier into the ground: The helical pier is rotated into the soil, and the torque is monitored to ensure it reaches the required level.
• Measuring torque: The torque measurement is essential for determining the soil's load-bearing capacity. Higher torque indicates stiffer soil, which can support more load.
• Securing the pier: Once the required torque is achieved, the pier is secured in place, and a bracket is attached to the footing of the structure.

Finalizing the Installation

After the helical piers are installed, the crew backfills the holes and compacts the soil to prevent future settling. The finished installation is typically below grade, making it invisible once the site is restored.

Applications of Helical Piers

Helical piers can be used in various applications, including:

• Existing Structures: They are often used to stabilize shifting foundations in existing buildings. For example, in a recent project, helical piers were installed to support a tilt-panel construction that had experienced significant shifting due to poor soil conditions.
• New Construction: Helical piers can also be incorporated into new construction projects, especially in areas with poor soil conditions. They allow for a stable foundation without the need for extensive excavation.

Foam Injection for Soil Stabilization

In addition to helical piers, foam injection is an effective method for stabilizing soil and filling voids beneath structures. This technique involves injecting a lightweight foam that expands to fill gaps and voids, providing support without adding significant weight to the soil.

Benefits of Foam Injection

• Quick Curing Time: Foam cures in about 15 minutes, allowing for rapid repairs and minimal disruption to ongoing operations.
• Cost-Effective: Foam injection can be significantly cheaper than traditional methods, such as pressure grouting, especially in cases where only void filling is needed.
• Soil Compaction: The foam expands and compacts the surrounding soil, reducing the risk of future settling.

Conclusion

Helical piers and foam injection are essential tools in the foundation repair and construction industry. Understanding their applications, installation processes, and benefits can help property owners and builders make informed decisions about stabilizing and supporting their structures. Whether dealing with existing buildings or new construction, these methods provide reliable solutions for ensuring structural integrity and longevity.