Why use a multiturn helix screw pile system in lieu of other piling options?
- Multiturn helix in Dense Ground Material are twice as effective in Compression load capacity compared to a Single Plate Helix of Similar Diameter.
- For the same Compression Load Capacity, a 50% smaller diameter Multiturn helix compared to a Single Turn Plate Helix is all that is required to carry the load.
- Smaller diameter Multiturn helix needs smaller Installation equipment, smaller lay down area and reduced transport costs due to lighter weight.
- Multiturn helix connect to Pile Shaft end with simpler, cheaper, stronger Buttweld Joint compared with Two sided weaker Fillet Spiral Welds on outer circumference of pile shaft.This means stronger and lower cost of pile manufacture.
- Transfer of Compression Load from Multiturn Cast helix onto end of pile shaft allows full 100% load capacity of Engineering Design of pile shafts as per AISC Design capacity tables for Hollow Structural Steels. Load from a Spiral welded plate helix transfers laterally into the pile shaft wall causing collapsing of pipe wall and or deformation of the plate helix at approx. 60% of the pipe shafts design capacity so smaller diameter shafts can be used to carry the same Compression load with Multiturn Helix.
- The casting process used in Multiturn manufacture allows metal to be placed in areas of helix receiving highest loads as per Sydney University Civil Engineering Research findings. Metal transferred from Tip of Flights ( low load areas ) to Flight junction with the body where loads are the greatest for any given helix means more effective metal use and lower unit cost.
- BHP have long stated that any steel installed below 1 metre from the ground surface in NON AGGRESSIVE soils will not undergo corrosion due to the lack of oxygen below the 1 metre mark. Thus steel piles embedded in concrete footings or pads will endure long term ( min 50 year service life ). This makes Steel Piles very acceptable and economically advantageous over concrete, timber or bored piers.
- Installation is independent of weather conditions and water table levels.
- Multiturn Screw Piles can have immediate load application post installation.
- Steel Screw Piles are much safer in Reactive Shrink / Swell soils due to deep placement below reactive levels and minimum friction occurring on the steel shaft.
- Cast Steel Helix with typical Ultimate Tensile around 600 kPa has much greater safety capacity over Wrought Plate Steel helix at around 460kPa Ultimate Tensile if pile becomes overloaded, thus minimising Catastrophic Failure