Configuration of screwpile components will be subject to: ground conditions, installation environment, structural loads and connection to structure method. Over 14 years of continued R&D by us has produced a range of screwpiles specifically engineered to suit those variation.
Standard configuration screwpiles suited to sands generally consist of a single base helix. Multiple helix screwpiles tend to be used on clay sites. Sites with very hard clays, weathered rock or limestone may require RET screwpiles. Standard screwpiles may have the piles shaft specified as concrete filled to assist in corrosion issues, however this is not always the case.
Standard screwpiles may be toe capped to stop water ingress prior to concrete filling. As with RET screwpiles the head of the pile can be in a number of configuration to suit the particular engineered application.
Where a building site soil conditions are likley to include weathered rock or limestone as the founding stratum special consideration needs to be given to the bearing elements at the toe of the screwpile. The toe of a standard screwpile is not designed for engagement into hard materials such as limestones, weathered rock or very hard clays resulting in the toe of the screwpile riding atop of the material. The helix located slightly up the shaft does not engage the hard material resulting in potential crushing of the hard strata or pile tip under load as the helical end bearing element is left suspended above the hard founding material.
RET screwpiles are specifically designed to engage hard materials up to 15Mpa. Limestones, weathered rocks and very hard clays are penitrated to a specified minimum depth so that the helix is sufficiently engaged in to the hard material. RET technology consists of Bizalloy helical plates (attack helix's) below the main end bearing helix and Bizalloy cutting profiles (attack points) welded to the toe of the screwpile. The RET components cut a specified cylinderical shape into the rock ensuring the screwpile is socketed into the rock strata.
RET technology is particularly advantagous where loose soils and water exist above the rock strata. RET is only suitable for compression screwpiles.