Helix Ground Screws

Ground screws, also known as helical piles or screw piles, are innovative foundation systems that provide a secure and stable base for various structures. They consist of a steel shaft with helical plates attached to them. These plates allow the ground screws to be easily rotated into the ground using machinery.
Ground screws have revolutionised construction practices by providing a reliable foundation solution that is versatile in different soil conditions while being time-efficient and environmentally friendly.

Ground screws are a type of displacement pile and are therefore based on one of the oldest forms of foundation construction – pile foundations, which have been used for thousands of years. As opposed to earlier versions made from wood, ground screws are galvanised steel pipes with a welded-on thread which is designed to support horizontal and vertical loads in the floor and is installed with the help of a ground screw driver. Using this type of foundation rids you of the need to displace any earth when building.

In principle, the ground screws work in exactly the same way as a standard screw would in the wall with a wall plug or when driven into a piece of wood. When the screw is driven in with some force, an interlocking connection forms between the screw and the wood. In this case, interlocking means that the screw interlocks with the wood and is firmly fixed into place.

If you drive a ground screw into the ground with sufficient clamping pressure, the interlocking happens in the same way. The welded thread helps the foundation to positively interlock with the ground. In addition, when the ground screw is driven in, the earth is displaced and compacted, causing an additional frictional connection between the ground and the shaft of the ground screw. Frictional connections are caused by frictional forces, which in this case is the surface friction between the steel pipe and the ground.

The subsoil check
Alongside the clarification about the subsoil with regards to its composition and load-bearing capacity, it's also very important to check whether there are any kind of pipelines running under the construction site before the foundation installation begins. This means that you can avoid unintentionally damaging gas, electricity, water or telecommunication lines, which would not only be an expensive mistake but also a very dangerous one.

Preliminary drilling makes the driving in easier
It's recommended that you perform a preliminary drilling at each of the ground screw installation points to ensure high levels of precision and to make the installation more efficient. These should be significantly smaller in diameter than the foundation that you will be installing. The drilling can be done either partially or cover the whole length. It should be done either with the help of a probing spike or by hand with a traditional impact drill.

Keep an eye on the spirit level
Depending on the application, you have to work very precisely. This means that the installation tolerances must be kept extremely low. This is necessary as then the load bearing points of the structure can later be exactly adjusted to the foundations. In addition, you must always keep an eye on the spirit level in order to ensure a perpendicular driving in. Tilting and too high installation tolerances can lead to an incorrect and unfavourable loading of the ground screws, which may in turn cause other problems, such as the bending of the ground screws, for example. This can lead to a decrease in the load-bearing capacity of the foundations.

Torque documentation creates acceptance
You should document the torque during the installation of the individual ground screws, even if no evidence is required. These values can be compared with the results of the load-bearing test which – if they match – not only confirms the quality of the installation but also increases the acceptance of the solution by everyone involved in the project. In most cases, the documentation can only be done manually.

Use the right machine
Last but not least, it is of course important to choose the right ground screw driver to ensure a proper installation. Here, there are a variety of different designs available to choose from. It may be an electric manual ground screw driver, a hydraulic excavator add-on or a drill-guided installation device which is available both as a self-driving caterpillar and an excavator add-on. Each machine has its own application-oriented, specific advantages which means that they can cover a wide range of application possibilities. For example, if precision is important for your project, a drill-guided machine is recommended, but with narrow and small construction sites, a manual ground screw driver is entirely sufficient.