Evaluation Report CCMC 13608-R
Pieux

The product is an earth anchor constructed of helical-shaped circular steel blades that are welded to a steel shaft. The blades are constructed as a helix with a carefully controlled pitch.

The anchors are available in three outiside diameters. The 60-mm-outside diameter has a wall thickness of 4.8 mm with helix blades either 200 mm, 250 mm or 300 mm in diameter and a thickness of 8 mm. The 73-mm-outside diameter has a wall thickness of 4.8 mm with helix blades either 250 mm or 300 mm in diameter and a thickness of 8 mm. The 89-mm-outside diameter has a wall thickness of 5.5 mm with helix blades either 250 mm, 300 mm or 350 mm in diameter and a thickness of 8 mm or 12.5 mm. All anchors come with a single blade and are either 2.1 m or 3.0 m in length.

The anchor type and blade diameter are chosen based on the bearing capacity of the soil and the load that the auger-installed steel pile is designed to support. The central shaft is used to transmit torque during installation and to transfer axial loads to the helical plates. The central shaft also provides most of the resistance to lateral loading. The foundation system comes with various other accessories, such as support plates to adapt to the building structure, extension shafts and connectors.

The steel shaft, blades and accessories conform to CSA-G40.21-04(R2009), “General Requirements for Rolled or Welded Structural Quality Steel/Structural Quality Steel,” 330 MPa. They have a galvanic coating that meets the requirements of CAN/CSA-G164-M92(R2003), “Hot Dip Galvanizing of Irregularly Shaped Articles,” 610 g/m³.

Figure 1 shows a typical steel pile with a single helical blade.

• The product may be used as part of a foundation system to support various constructions, provided that it is installed according to the manufacturer’s current instructions and within the scope of this Report.
• When the product is installed in granular soil or silt, there is a direct relationship between the applied torque and the allowable compressive and tensile loads. Table 3.1 indicates the allowable compressive and tensile loads as a function of the applied torque.
• When the auger-installed steel pile is installed in a cohesive soil, such as clay or a soil with granular material that exceeds 200 mm in diameter, the relationship between the applied torque and the allowable compressive and tensile loads is not as predictable. When it is installed in such soils, the allowable compressive and tensile loads have to be confirmed by on-site load tests. These load tests are also required if the allowable loads need to be greater than those stated in Table 3.1. The tests need to be conducted under the direct supervision of a professional geotechnical engineer, skilled in such design and licensed to practice under the appropriate provincial or territorial legislation.
• In all cases, a registered professional engineer skilled in such design and licensed to practice under the appropriate provincial or territorial legislation must determine the number and spacing of the auger-installed steel piles required to carry the load. A certificate attesting to the conformity of the installation and the allowable loads for the piles must be provided.

  Table 3.1.  Allowable Compressive and Tensile Loads for the Proposed Auger-installed Pile in Granular Soil or Silt^{Table 1 footnote 1}

  Applied Torque		Allowable Loads
  		Compression		Tension
  Nm	(lbf)	kN	(lb)	kN	(lb)
  678	500	16	3600	10	2250
  1017	750	22	4950	15	3375
  1356	1000	28	6300	20	4500
  1695	1250	34	7650	25	5625
  2034	1500	40	9000	30	6750
  2373	1750	46	10350	35	7875
  2712	2000	52	11700	38	8550
  3051	2250	58	13050	40	9000
  3390	2500	64	14400	42	9450

  Note to Table 3.1:

  Footnote 1

  The allowable loads identified in this Table are only valid when the product is installed in granular soil or silt.  Special attention is required when the auger-installed steel piles are installed in a recently backfilled site or where the granular material exceeds 200 mm in diameter or in cohesive soils. In these cases, Table 3.1 does not apply and the allowable loads need to be determined by on-site confirmatory testing.

  Return to table 1 footnote 1 referrer

• The installation of the auger-installed steel pile must be carried out as per the manufacturer’s instructions. The anchors must be screwed into the ground to below the frost line using mechanized equipment. The anchor is rotated into the ground with sufficient applied downward pressure (crowd) to advance the anchor one pitch distance per revolution. The anchor is advanced until the applied torque value attains a specified value. Extensions are added to the central shaft as needed. The applied loads may be tensile (uplift), compressive (bearing), shear (lateral), or a combination thereof. Helical anchors are rapidly installed in a wide variety of soil formations using a variety of readily available equipment. They are immediately ready for loading after installation.
• When the product is installed in a soil where the conditions are corrosive to steel, adequate protection to the exposed steel must be provided.
• The installer of the proposed auger-installed steel piles must be certified by Pro Pieux Inc. Using approved equipment, the installer must follow the manufacturer’s installation instructions and the uses and limitations specified in this Report. Each installer must carry a certification card bearing their signature and photograph.
• Each auger-installed steel pile must be identified with a label containing the following information:
  • manufacturer’s identification; and
  • the phrase “CCMC 13608-R.”

The proposed auger-installed steel piles were tested in accordance with the requirements of ASTM D 1143/D 1143M-07, “Standard Test Methods for Deep Foundations Under Static Axial Compressive Load,” ASTM D 3689-07, “Standard Test Methods for Deep Foundations Under Static Axial Tensile Load,” and ASTM D 3966-07, “Standard Test Methods for Deep Foundations Under Lateral Load.”

Testing was conducted on three different sites. The first and third sites had granular soil, and the second had clay soil. A series of 16 tests were performed. The intent of the testing was to determine a correlation between the torque applied during installation and the allowable loads. In the granular and silt-based soils there was a good correlation between the torque applied during installation and the allowable loads. For the compressive and tensile loads noted in Table 3.1, the factor of safety varied from 2.0 to 2.5. For the lateral loads, no correlation was possible. For the testing that was conducted on the auger-installed steel pile in a cohesive soil, such as clay, the correlation between the applied torque and the allowable loads was not as predictable.