Screwpiles are steel screw-in piling and a ground anchoring system that is used for building foundations (pile foundations). They are manufactured from hollow steel sections for anchor shafts. They come in varying sizes depending on the intended purpose. The anchor shafts, also called pile shafts, transfer the load of the building to the steel piles. Welded to the steel piles are steel plates. These provide more stability and firm anchorage for the building. Their spacing and number depends on the site ground conditions. The rate of environmental corrosion, geothermal parameters, minimum design life and the combined load of the structure also affect the shape, diameter, and number of the steel plates. You migh also want to read this very helpful explanation of helical anchors.
Building code standards relevant to screwpiles apply. These piles are installed into the ground by winding them into the ground just like a screw would be wound into wood. Earthmoving equipment with rotary hydraulic attachments is used for installation. Elite drive attachments in these machines attach the screw pile to the machine. It is worth noting that proper installation of the screwpile contributes significantly to its performance.
Also referred to as screw anchors, steel screw-in foundations, piertech helical piers, or screw piers, screwpiles were first described by Alexander Mitchell, an Irish civil engineer in 1848. Between 1800 and 1900, screw piers were made from wrought and cast iron but these materials have been abandoned due to their low tension and bearing strengths. During the recent past, engineers have developed a composite technology to replace steel in small screw anchors.
The design of these piles is based on standardized geotechnical and structural standards. Designers may use computer design software to design screw piles like piertech . The software is developed by field testing of the varying tension anchor and compression pile configurations in different soil types. World steel databases and extensive field testing provide key information on of corrosion of screwpiles and how it can be prevented.