Understanding Load Testing for Helical Piles

When it comes to deep foundation systems, helical piles (also called helical piers or screw piles) have become a preferred choice for commercial, industrial, oil & gas, and energy infrastructure projects. Their versatility, speed of installation, and ability to handle significant loads make them an attractive solution across industries.

But before these piles can safely support a structure, one crucial step must take place: load testing. Load testing verifies performance, ensures compliance with engineering requirements, and ultimately provides peace of mind to contractors, engineers, and owners.

In this article, we’ll break down everything you need to know about load testing for helical piles—what it is, why it matters, the different methods used, and how it impacts project success.

What Is Load Testing for Helical Piles?

Load testing is the process of applying controlled forces to a helical pile to confirm its load-bearing capacity. In other words, it’s how we prove that the pile can safely carry the loads it was designed for—whether that’s compression (downward), tension (uplift), or lateral forces.

Load testing helps answer critical questions like:

• Can this pile safely support the design load?

• How much settlement or deflection occurs under load?

• Does the pile meet local code requirements and safety factors?

By conducting these tests, engineers validate design assumptions, avoid failures, and establish confidence in the foundation system before full-scale construction moves forward.

Why Is Load Testing Important?

1. Safety and Structural Integrity

Load testing confirms that piles perform as expected in real-world conditions. Without testing, assumptions made during the design phase may go unverified, putting structures at risk of settlement, tilt, or even catastrophic failure.

2. Code Compliance

Many building codes (including ICC-ES and ASTM standards) require load testing on a percentage of installed piles. This ensures foundations are not only designed properly but installed correctly.

3. Project Efficiency

Testing reduces uncertainty. By knowing the exact load capacity of piles, engineers can avoid overdesigning foundations (which wastes materials and increases costs) or underdesigning them (which leads to risk and potential rework).

4. Cost Savings

While load testing has an upfront cost, it can save significant money by preventing over-installation, ensuring compliance, and reducing long-term maintenance or failure risk.

Types of Load Testing for Helical Piles

There are several types of load tests used in helical pile projects. Each serves a different purpose, and the right method depends on project requirements, soil conditions, and governing standards.

1. Compression Load Testing

This test measures how a pile performs under downward loads—the same way a building or structure pushes weight into the ground. It evaluates settlement and ensures piles won’t compress excessively under structural loads.

Procedure:

• A test frame or reaction piles are installed.

• Hydraulic jacks apply load to the test pile.

• Settlement is measured with dial gauges or electronic sensors.

Compression tests are critical for projects like industrial plants, warehouses, and energy facilities where piles must support massive vertical loads.

2. Tension (Uplift) Load Testing

This test checks how piles resist forces pulling upward. Tension forces occur in applications like guyed towers, utility poles, anchored retaining walls, and pipelines.

Procedure:

• The test pile is pulled upward using hydraulic jacks.

• Reaction piles or dead weights provide resistance.

• Engineers measure displacement under increasing load.

Uplift testing ensures piles won’t fail when subjected to wind, seismic, or overturning forces.

3. Lateral Load Testing

In this test, horizontal forces are applied to the pile to evaluate resistance to sideways movement. Lateral testing is especially important for marine structures, bridges, or piles supporting tall slender structures exposed to wind or water.

Procedure:

• Hydraulic jacks push the pile sideways.

• Deflections are recorded as loads increase.

Lateral testing is less common than compression and tension testing but is critical in specialized applications.

4. Proof Load Testing

Proof testing is performed on a percentage of installed piles to confirm installation quality. Instead of full-scale capacity verification, proof testing applies a predetermined design load (with a safety factor) to ensure piles meet minimum requirements.

This type of test is fast, cost-effective, and commonly required by engineers and building inspectors.

How Load Testing Works: Step-by-Step

While procedures vary by test type, most load testing follows a structured process:

1. Select Test Piles
   Engineers choose piles representative of field conditions—often including the “worst-case” location in terms of soil or installation depth.

2. Install Reaction System
   Reaction piles, frames, or anchors are installed to provide a stable platform for applying load.

3. Apply Loads Incrementally
   Hydraulic jacks or loading equipment apply loads in stages, typically in 25–50% increments of the design load.

4. Measure Deflections or Settlement
   Precise instruments record pile movement under each load step.

5. Analyze Results
   Engineers plot load vs. displacement curves to determine ultimate capacity, stiffness, and performance against design criteria.

6. Document Findings
   A full report confirms compliance with project specifications and regulatory standards.

Industry Standards and Guidelines

Load testing for helical piles is governed by several industry standards, including:

• ASTM D1143/D1143M – Standard Test Method for Piles Under Static Axial Compressive Load

• ASTM D3689 – Standard Test Method for Piles Under Static Axial Tensile Load

• ASTM D3966 – Standard Test Method for Piles Under Lateral Load

• ICC-ES AC358 – Acceptance Criteria for Helical Foundation Systems and Devices

Compliance with these standards ensures tests are consistent, reliable, and recognized by building officials and engineers across the U.S.

Factors That Influence Load Test Results

Several factors impact the outcome of a helical pile load test:

• Soil Conditions – Weak, loose, or layered soils can reduce pile performance compared to dense or uniform soils.

• Pile Design – Shaft diameter, helix size, and number of helices all affect load capacity.

• Installation Torque – Higher installation torque generally correlates with higher load capacity.

• Installation Method – Proper alignment, depth, and torque monitoring are critical for reliable results.

• Groundwater Levels – Saturated soils may reduce capacity and increase settlement.

Understanding these variables helps engineers interpret test results accurately and adjust designs if necessary.

Common Misconceptions About Load Testing

1. “Load testing is unnecessary if torque values are high.”
   While torque is a good predictor of capacity, it’s not a substitute for a full load test. Testing provides real-world verification.

2. “Load testing adds too much cost.”
   In reality, load testing prevents costly failures, rework, and overdesign—often saving money in the long run.

3. “All load tests are the same.”
   Each test type (compression, tension, lateral) serves a unique purpose. Using the right method is essential for reliable results.

Real-World Applications of Load Testing

Load testing isn’t just theory—it’s applied across industries where failure is not an option:

• Energy Infrastructure – Supporting transmission lines, substations, and solar farms.

• Industrial Facilities – Heavy equipment foundations, storage tanks, and processing plants.

• Oil & Gas – Securing pipelines, offshore platforms, and refining facilities.

• Commercial Construction – Warehouses, office buildings, and multi-story developments.

• Transportation – Bridges, retaining walls, and highway structures.

Each of these applications depends on verified foundation performance, making load testing a cornerstone of project success.

The Role of US Helicals in Load Testing

At US Helicals, we don’t just install piles—we ensure every foundation we build is proven, tested, and trusted. Our team:

• Performs full-scale compression, tension, and lateral load testing.

• Follows ASTM and ICC-ES standards.

• Uses state-of-the-art monitoring equipment.

• Provides detailed reports for engineers, contractors, and inspectors.

By combining decades of field expertise with rigorous testing procedures, we deliver foundation solutions that stand the test of time.

Conclusion

Load testing is more than a box to check—it’s the backbone of foundation reliability. By confirming real-world performance, meeting code requirements, and optimizing project efficiency, load testing ensures that helical piles perform exactly as intended.

For contractors, engineers, and project owners, understanding load testing means understanding how risk is minimized and confidence is maximized.

At US Helicals, we take pride in providing deep foundation solutions backed by thorough testing and proven results. When performance matters, load testing ensures your project is built on solid ground.