Projected Helical Plate Areas

  • The projected area of an individual helix is the area of the helix plate less the cross sectional area of the shaft.
  • The sum of the projected total area is required to determine the capacity of a helical anchor.
  • Helical Anchors, Inc. usually recommends an angle of approximately 60 degrees and no more than 90 degrees angle.
  • Helical plates may be cut to a maximum of 90 degrees angle to improve penetration in rocky soils.
  • The angle of the cut can reduce the projected area by approximately 20 to 25% and must be taken into consideration when designing.