GUIDE TO ANCHORING TYPES:
DECIDING BETWEEN ANCHORING TYPES
This comprehensive guide aims to highlight the key differences between self-drilling anchors (SDAs) – also known as hollow bar micropiles – and standard helical piles” or “self-drilling anchors” (SDAs) (also known as hollow bar micropiles) and standard helical piles.
Keep reading to learn how experts in deep foundation construction rely on Intech Anchoring Systems.
HELICAL ANCHORS VS. SELF-DRILLING ANCHORS
In the construction industry, particularly concerning foundational integrity, selecting the appropriate anchoring systems is paramount. Among the leading choices available are self-drilling anchors (SDA) and the standard helical piles. Both options provide unique advantages suited for various applications, requiring geotechnical engineers to make informed decisions that with project specifications.
The two main considerations when differentiating the two is:
- What type of load is it?
- How are the soil conditions?
| Differentiator | Helical Anchors | Hollow Bar Anchors |
|---|---|---|
| Load | Light to Moderate* | Moderate to Very High (or shallow bedrock) |
| Type of Soil | Soft soil, loose sand and lean clay | Any soil |
| Soil Conditions | Minimal obstructions | Boulders, Cobbles, Existing Footings |
| Piles at Capacity via | In Bearing Plates | Skin Friction (along length) |
| Pressure Bulb | 2:1 slope | No lateral effects |
| Grouting | Optional | Yes, continuous |
| Column Diameter | Plate Size (6-14" diameter) | Grout Size (4-8" diameter) |
| Spatial Requirements | 3" spacing | 3" spacing |
| Common Applications | Deep Foundations, Earth Retention, Foundation Repair | Deep Foundations |
Generally helical anchors are used for light to moderate loads. However, if using grouted helical micropiles – loads may reach up tp 500 tons.
HELICAL PILING EQUIPMENT
Manufactured from the industry’s strongest steel – our helical anchors and drive kits provide a sturdy solution for deep foundation requirements.
Requiring zero heavy equipment and no grouting necessary, helical anchors equate to a cost-effective and environmentally-friendly product for soil stabilization under your toughest builds.
Plus, all steel can be cut to customized lengths if necessary.
SIZES AVAILABLE
Square:
- 1.25″
- 1.5″
- 1.75″
Round:
- 2.875″
- 3.5″
EQUIPMENT REQUIRED
- Rock Drill
- Steel Helicals
- Drive Kit
- Proper Sized Drill Bits
HOLLOW BAR MICROPILE ANCHORS
Our in-house manufactured Magnacore® Self-Drilling Anchor from Intech Anchoring exemplifies innovation designed to address challenging soil conditions that may impede traditional micropile solutions.
- R32
- R38
- R51
- T40
- T52
- T76
Standard lengths of 4.92 ft (1.5 m) and 9.84 ft (3 m) are available, with options for custom orders, including lengths and sizes tailored to unique project needs, alongside a comprehensive selection of accessories.
SIZES AVAILABLE
- R32
- R38
- R51
- T40
- T52
- T76
EQUIPMENT REQUIRED
- Excavator
- Rock Drill
- Grout Plant
- Proper Sized Drill Bits
USING HELICAL PILES
- Used for Soft Soils
- Light to Moderate Loads
- Minimal Ground Obstructions
Helical piles gain capacity from in-bearing at the plates rather than the length of the pile.
The pile diameters are generally larger due to the plates being driven into the ground which can be from 6-14 inches diameter.
As the pile gets loaded the load is transmitted down the shaft onto the plates. When the plates load the soil – it creates a pressure bulb which is terminated at 2 diameters down from where the load is applied.
To avoid isobar interaction – keep spacing at 3″ diameters.
USING HOLLOW BAR ANCHORS
- Good in Any Soil Condition
- Uses Steel & Grout to Drive Piles
- Limited-Access Sites
- Grouting Equipment Necessary
Self-drilling anchors (SDAs) like our Magnacore® Hollow Bar solution – excel in diverse geological conditions, even unstable ones, making them perfect for complex projects.
They penetrate deeper than traditional rock bolts, reducing drilling resistance for deep foundations. With adjustable lengths for tight spaces, their drilling and grouting integration speeds up processes, ensuring timely completion in fast-paced construction.
ADVANTAGES OF HELICALS
- Minimal Vibration/ Soil Displacement
- Instant Load Capacity
- Installation Torque Continuously Monitored
- No Heavy Equipment Required
We provide ICC-ES evaluated helicals, made with 98% recycled American 80 KSI steel and integral forged couplings. The line features a more traditional small diameter square shaft (1.5” and 1.75” – up to 70 kips) or round pipe (2 7/8” to 5.5” OD – up to 235 kips).
These piles can also be grouted to achieve higher loads, increase lateral capacity, eliminate buckling concerns, or protect the steel.
Helical piles can be large diameter piles up to 20” OD with up to 500 tons of capacity.
ADVANTAGES OF HOLLOW BAR
- Exceptional Suitability Across Geological Conditions
- Unlimited Drilling Depth
- Compact Construction in Limited Spaces
- Streamlined Construction Process
Hollow bar micropiles, like the Magnacore® Self Drilling Anchor, provide a cost-effective and efficient foundation solution in challenging environments, such as collapsible soils or areas with obstructions.
The streamlined installation process uses the hollow bar for drilling and grout injection, reinforcing the micropile and enhancing load-bearing capacity.
This innovative technique avoids open-hole drilling, ensuring quick and reliable installation even in difficult conditions, making Magnacore® micropiles a valuable asset in modern construction.
