Micropiles

Micropiles transfer compressive loads safely and sustainably into load-bearing strata to stabilize foundations.

These piles are used for a range of applications and can be installed in restricted access locations.

Characteristics

  • Micropiles can retrospectively reinforce and strengthen foundations in locations with limited access

  • Additional capacity can be achieved in weak soils through the application of post-grouting within the pile shaft

  • Tension micropiles can be used in approach slabs to tunnels and station boxes—reducing slab thickness and enabling significant savings on concrete and reinforcement

Micropiles are used in

Micropiles can be installed into load-bearing strata with specialist lightweight drilling equipment in restricted access locations—such as narrow basements, under bridge decks, or where barge installation is necessary.

Test loads are carried out to prove the aptitude of the chosen system for the on-site conditions on-site.

How micropiles work

Micropiles act as a passive foundation system. A GEWI or GEWI-Plus Threadbar is inserted into a borehole and centered using a spacer. The borehole is then filled or pressure-grouted with cement mortar from the bottom up. 

Corrosion protection

The grout transfers the force to the soil by skin friction and also provides standard corrosion protection. In locations where the cement grout cover does not offer sufficient protection and the foundation soil or groundwater is aggressive, double corrosion protection micropiles are available.

As in solid construction, the alkaline environment of the surrounding cement grout coverage is used for protecting the reinforcing steel.  In aggressive conditions, the steel reinforcement is encapsulated in plastic corrugated sheathing and the annular space is grouted at the factory. This design is used in case of tensile forces, for example in permanent uplift control, because cracks in the coverage can decrease the passivation effect of the cement grout.

System Flexibility

DYWIDAG micropiles are skin friction piles and can transfer compression, tensile, and alternating loads. The continuous threadform of GEWI or GEWI Plus threadbars, enables the bars to be cut and coupled or terminated at any point.

Projects

Solid threadbars or self-drilling hollow bars

Solid threadbar diameters 16-75mm

Self-drilling hollow bar diameters 25-103mm

Installed in restricted access locations

Tension or compression loadings

Permanent or temporary options