Helical Anchor
The "Helical anchor" is selected as an "Anchor type" in the combo list in the dialog window "New anchor".
The Helical anchor requires the input of:
- Production set - user-defined (the user input of parameters) or the anchor from the catalog (Helical Anchors, Mac Lean, Chance...). The anchors from the catalog are specified by the other parameters (type of shaft, Nr. of helix, thickness, and material of helix) - if the selected combination is not manufactured, the name of the anchor is empty and editing cannot be finished
- Location of anchor - depth, length, slope...
- Type of shaft profile - circle (pipe), square
- Stiffness of anchor - elasticity modulus E
- Parameters for verification of anchor (Strength of anchor, Pull-out resistance from the soil is described below)
Anchor parameters input
Calculation of pull out resistance from soil:
Option "input"
This option is required for user-defined anchors. It is necessary to enter the value of pull out resistance from soil Re [kN, lbf]. The table with dimensions and locations of each helix is only for the visualization of the anchor and internal stability check.
Option "calculate"
This option is available only for anchors from the catalog. The dimensions and locations of each helix are determined by the manufacturer. The pull out resistance from the soil is calculated according to this formula:
where: | n | - | number of the helix |
Rh,i | - | maximal bearing capacity of the helix, determined by the manufacturer | |
c | - | cohesion of the soil | |
σz | - | geostatical stress | |
Nc,Nq | - | Meyerhof´s coefficients for bearing capacity | |
Ai | - | the area of helix |
The bearing capacity coefficients can be calculated in standard way:
where: | φ | - | angle of internal friction (for φ = 0 is Nc = 2+π) |
or according to CHANCE Design Manual:
Literature:
Chance - Technical Design Manual, Edition 4