Helical piles are also termed as screw piles which are used to construct deep foundations and serve as screw-in and ground anchoring system. These are consists of various sizes of hollow tubular section for pile foundation and anchors shaft.
Structural load is transferred through pile shaft. Helical plates are welded steel plate connected with pile shaft by welding. The number and diameter of helices and their position along pile shaft and thickness of plate are determined base on:
b. Geotechnical parameters
c. Ambient corrosion parameters
d. Life cycle of structure
Dear reader we will learn IBC requirements for helical piles here.
The helical piles should be analyzed and manufactured according to allowable engineer practice so that the piles are capable to resist installation stress and service loads. Diameter of central shaft, size, number and thickness of bearing plates should be sufficient to sustain design loads.
This type of piles should be installed providing sufficient embedment and should capable to resist torsional forces as derived by professional engineer. The applied torque should not exceed (during installation) maximum allowable torque of helical pile.
Allowable axial load Pa for helical pile design should be determined according to:
Where Pu is determined by:
a. Pu=(Ultimate bearing capacity of soil or rock)X ∑(areas of bearing plate in helical pile)
b. Pu=Ultimate capacity based on installation torque (well documented correlation should be used).
c. Ultimate capacity based on load tests.
d. Ultimate axial load bearing capacity of the pile shaft.
e. Ultimate axial load bearing capacity of coupling of pile shaft
f. Ultimate axial load bearing capacity of bearing plates fixed to helical pile.