How Deep do Helical Piers Need to be Installed to Reach Load-bearing Soil?
The installation depth for helical piers is not a fixed number; instead, it is determined by the specific subsurface profile and the need to reach stable, load-bearing strata. According to the provided guide, depth requirements can vary significantly based on soil type:
- Soft Clay: Approximately 5–15 feet.
- Silty Clay or Clay Loam: Approximately 8–20 feet.
- Loose to Dense Sand: Approximately 10–25 feet.
- Gravel or Sandy Gravel: Approximately 12–30 feet.
### Determining the Correct Depth To ensure the pier has reached competent soil, contractors use two primary methods:
- Geotechnical Investigation: Soil borings and test pits identify the depth of the load-bearing strata before installation begins.
- Real-Time Torque Monitoring: As the pier is screwed into the ground, a hydraulic torque motor measures resistance. This torque reading is correlated to soil capacity using ICC-ES AC358 formulas. The installation continues—often using extensions—until the required torque and design depth are achieved.
At a minimum, piers are typically installed beyond the frost line to prevent movement caused by freeze-thaw cycles.
Related FAQs
-
When should You Use Round Shaft Versus Square Shaft Helical Piers?
Read More »: When should You Use Round Shaft Versus Square Shaft Helical Piers?The choice between round shaft and square shaft helical piers depends on your project’s soil conditions, load requirements, and structural goals. Both designs serve as advanced earth anchoring systems, but they excel in different environments: When to use Round Shaft…
-
Which Shaft Type has Better Torsional Strength During Installation?
Read More »: Which Shaft Type has Better Torsional Strength During Installation?The answer depends on the specific application and soil conditions, as both round and square shafts offer distinct advantages in torsional strength: Round Shafts: These are noted for their superior torsional performance due to an axisymmetric geometry. This circular cross-section…
-
Should I Hire a Professional for Concrete Repair?
Read More »: Should I Hire a Professional for Concrete Repair?Hiring a professional for concrete repair in Denver is highly recommended due to the region’s complex geological and regulatory environment. Professionals possess the expertise to distinguish between minor hairline cracks and significant structural issues caused by Denver’s expansive clay soils…
-
What Questions should I Ask Concrete Contractors in Denver?
Read More »: What Questions should I Ask Concrete Contractors in Denver?When hiring concrete contractors in Denver, it is essential to ask specific questions to ensure they can handle the region’s unique geological challenges, such as expansive clay soils and freeze-thaw cycles. Based on local requirements and industry standards, you should…
-
How are Push Piling Piers Used for Foundation Repair in Texas?
Read More »: How are Push Piling Piers Used for Foundation Repair in Texas?In Texas foundation repair, push piers (also referred to as push piling or hydraulically driven sections) are utilized to stabilize sinking structures, particularly in areas with expansive clay soils like Houston, Dallas, and San Antonio. The process involves several technical…