Magnacore Self-Drilling Anchors

The Magnacore® Self Drilling Anchor (SDA) from MDTI is a hollow bar injection-bore micropile that serves as an economical solution for challenging soil conditions where installing conventional micropiles may not be the best option. For example, those with collapsible soils (those not conducive to open-hole drilling), large boulders, or other obstructions.

The micropile is formed in a single, top-down operation by the injection of a high-pressure, neat cement grout mixture that is pumped through the bar, while also serving as the drill string. The neat grout mix exits through ports at the end of the sacrificial bit and permeates into the looser adjacent soils forming a competent reinforced grout column.

Solid Bar Compared to Hollow Bar

Solid Bar

  • Predrilling required
  • Limited to shallow rock
  • Very stiff throughout soil strata
  • Casing needed in soft soils
  • Pre/Post grouting required
  • Several pieces of equipment

Magnacore SDA Hollow Bar

  • No predrilling
  • Rock at any depth
  • Can be installed in all soil types
  • Casing for lateral loads
  • Grouting completed during install
  • Only need rock drill & grout plant

Magnacore Applications

  • New construction
  • Underpinning
  • Settlement/stabilization
  • Earth retention
  • Slope stabilization
  • Tunneling

Benefits of SDAs

  • Difficult soil conditions
  • High installation rate
  • Limited access
  • No casing required
  • Extra corrosion protection
  • Decreased labor & material cost

Components of the Magnacore Self-Drilling Anchor

  1. Hex Nut
  2. Termination Plate for new construction or bracket for underpinning
  3. HDPE Pipe for unbonded length or additional corrosion protection
  4. Soil Cement Grout Body
  5. Final Injection Grout
  6. Magnacore Self-Drilling Anchor Bar allows injection while serving as drill strong
  7. Coupler
  8. Centralizer to keep the micropile centered in the hole to allow for optimal grout cover
  9. Sacrificial Bit
  10. Grout Flushing Holes

Magnacore Sacrificial Bits

The holes in each bit allow the grout/drilling solution to flow as the SDA is advanced, simultaneously creating the column.

  • Tungsten Carbide Button Bit for hard rock (Limestone, shale)
  • Tungsten Carbide Cross Cut Bit for softer rock (sandstone, soft shale, or fractured rock)
  • Clay Bit ideal for mixed fills and clay

Magnacore Specifications

U.S. Measurements

Bar Type R32S R38N R51N T40/16 T52/26 T76S
Outer Dia 1.26 in 1.50 in 2.01 in 1.57 in 2.05 in 2.99 in
Inner Dia 0.59 in 0.75 in 1.18 in 0.63 in 1.02 in 1.77 in
Area 0.81 in2 1.09 in2 1.66 in2 1.40 in2 1.99 in2 3.89 in2
Ultimate Tensile Load (Pu) 80.93 kip 112.40 kip 179.85 kip 148.37 kip 208.85 kip 427.14 kip
Yield Load (Py) 62.95 kip 89.92 kip 141.63 kip 118.02 kip 164.11 kip 337.21 kip
Ultimate Tensile Stress (Fu) 99.96 ksi 103.49 ksi 108.42 ksi 105.82 ksi 104.71 ksi 109.80 ksi
Yield Stress (Fy) 77.75 ksi 82.79 ksi 85.38 ksi 84.08 ksi 82.28 ksi 86.68 ksi
Weight 2.76 lb/ft 3.70 lb/ft 5.64 lb/ft 4.77 lb/ft 6.79 lb/ft 13.24 lb/ft

Metric

Bar Type R32S R38N R51N T40/16 T52/26 T76S
Outer Dia 32 mm 38 mm 51 mm 40 mm 52 mm 76 mm
Inner Dia 15 mm 19 mm 30 mm 16 mm 26 mm 45 mm
Area 520 mm2 700 mm2 1070 mm2 905 mm2 1290 mm2 2510 mm2
Ultimate Tensile Load (Pu) 360 kN 500 kN 800 kN 660 kN 929 kN 1900 kN
Yield Load (Py) 280 kN 400 kN 630 kN 525 kN 730 kN 1500 kN
Ultimate Tensile Stress (Fu) 690 n/mm2 715 n/mm2 750 n/mm2 730 n/mm2 720 n/mm2 760 n/mm2
Yield Stress (Fy) 540 n/mm2 570 n/mm2 590 n/mm2 580 n/mm2 570 n/mm2 600 n/mm2
Weight 4.1 kg/m 5.5 kg/m 8.39 kg/m 7.1 kg/m 10.1 kg/m 19.7 kg/m

Why MDTI?

In addition to materials and service, MDTI will provide continual support through the entire project, including: engineering/design, on-site support, load testing, installation expertise, competitive pricing, and rental equipment.

Call us at 888-262-7797 for more information or to receive a custom product quote.