Strengthening using mini-piles, root piles, and helical piles (capable of of working in confined spaces)

Micro-piles

Stap  already has a large experience in working with micro-piles.

In very general terms, the work consists of inserting a steel tube into a hole previously drilled in the ground and then sealing it according to the site's geotechnical conditions and the projected stress level.

After sealing the tube (space between the tube and the hole with a cement grout), it may be necessary to proceed with injection (depending on the project). In order to fully comply with its quality requirements, Stap  always uses a technology known as selective repetitive injection (SRI) to install micro-piles.

Stap  is particularly well equipped to execute this type of job in inaccessible places where it is hard to install drilling equipment.

Helical piles

This piling system is particularly useful to strengthen foundations because it is easy to install, minimally intrusive, and does not require any subsequent injections.

Formed by a rod around which one or more round helices are fitted, these piles allow contact stresses around the entire shaft to be mobilised, with a load capacity equal to the sum of the load capacities of each helix.

The method has another, considerable, advantage: It makes it possible to measure the load capacity through the installation torque, thus eliminating uncertainties often associated with special foundations such as mechanical properties of the soil and their relationship with the pile's load capacity.

This systems allows absortion of both compression and traction forces, and is thus prescribed for both strengthening and underpinning of foundations and for anchorages and tie-rods, for forces of up to 100 kN per helix, depending on the type of pile and terrain.

There is also a set of special supports that a perfect pile/structure connection, designed to allow possible load transfers and the application of pre-stressing.