Driven RR® micropile with effective splicing technology
RR® micropiles offer quick and cost-effective splicing, minor displacement of soil, minor vibration disturbance and high installation strength. They are installed by impact driving or jacking.
Micropile pipes and elements
The RR® micropiles are delivered either as micropile pipes or as ready-made micropile elements with an external sleeve splice at one end of the element.
Splicing of RR® micropiles
The RR® micropiles utilize friction-based splices that meet the requirements set for rigid splices in the EAD 200005-00-0103, a base document for acquiring CE marking for steel piles, and in the Finnish national annex to EN 1993-5.
- In RR75 - RR220 micropiles, the splice is an external double conical sleeve splice.
- Keeping the external splice in place during driving is ensured by welding, which is done at the factory as the splice is made. No welding of the splice is needed on site.
- RR270 - RR320 micropiles are spliced by welding.
If splicing is done by welding, SSAB’s RR® and RD® micropile design and installation manual provides recommendations concerning the creation of welded splices.
Usually a bearing plate is installed at the upper end of RR® micropiles to transfer loads from the superstructure to the micropile. The bearing plate is centred on the micropile shaft by an internal sleeve, which serves to keep the bearing plate in place.
The mechanically attached micropile shoes of RR® micropiles, bottom plates and rock shoes, meet the requirements of PO-2016. The rock shoe dowel is made of hardened special steel, which ensures good penetration into bedrock.