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Micropiles

RR® and RD® micropiles

Micropiles offer an effective and convenient way to implement the piling

The easy-to-use and cost-efficient splicing method allows quick installation of RR® and RD® piles with minimal material waste.

Micropiles consist of a longitudinally welded steel pipe, mechanical splices, a pile tip and a bearing plate.

The standard lengths of the pile elements, the sectional properties of the piles and the steel grades, see SSAB’s RR® and RD® piles design and installation manual.

 

Applications:

  • Office and business buildings
  • Industrial buildings
  • Residential buildings
  • Public buildings
  • Road and railway structures and bridges

RR® pile

Driven RR® micropile with effective splicing technology

RR® piles are micropiles that offer quick and cost-effective splicing, minor displacement of soil, minor vibration disturbance and high installation strength. RR® micropiles are installed by impact driving or jacking.
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RR-pile

 

RR® pile

Driven RR micropile with effective splicing technology

RR piles are micropiles that offer quick and cost-effective splicing, minor displacement of soil, minor vibration disturbance and high installation strength. RR micropiles are installed by impact driving or jacking.

Structure:

Pile pipes and elements

The RR piles are delivered either as pile pipes or as ready-made pile elements with an external sleeve splice at one end of the element.

Splicing of RR piles

The RR piles utilize friction-based splices that meet the requirements set for rigid splices in the Finnish national appendix to EN 1993-5.

  • In RR75 - RR220 piles, 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.
  • RR140 - RR220 piles can be extended also with an internal splice if necessary.
  • RR270 - RR320 piles are spliced by welding.


If splicing is done by welding, SSAB’s RR and RD pile design and installation manual provide recommendations concerning the creation of welded splices.

Bearing plate

Usually a bearing plate is installed at the upper end of RR micropiles to transfer loads from the superstructure to the pile. The bearing plate is centred on the pile shaft by an internal sleeve, which
serves to keep the bearing plate in place. 

Pile shoes

The mechanically attached pile shoes of RR  piles, bottom plates and rock shoes, meet the requirements of PO-2011. The rock shoe dowel is made of hardened special steel, which ensures good penetration into bedrock.

RD® pile

Drilled micropiles for drilling in difficult ground conditions

RD® piles may be drilled through all natural soil layers all the way into bedrock, with small deviations in position and inclination.
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RD-pile

RD® piles

Drilled micropiles for drilling in difficult ground conditions

The piles may be drilled through all natural soil layers all the way into bedrock, with small deviations in position and inclination.

Structure:

RD piles are delivered either as pile pipes or as ready-made pile elements with threaded heads.  

An RD pile comprises:

  • A bearing plate installed on the upper end of pile
  • An external threaded sleeve
  • Extension pipe (both ends are threaded)
  • Starter pile (one end is threaded)
  • A casing shoe and reamer bit (in concentric drilling) at the lower end of the pile

 

Threaded sleeve

RD piles are spliced either by an external threaded sleeve or by welding. The advantages of a threaded sleeve are:

  • Easy and quick splicing
  • High fatigue strength
  • High-quality end result even in difficult installation conditions

SSAB's threaded sleeves meet the strength and stiffness requirements of EN 1993-5, Finnish national annex for mechanical splices. The tensile strength of a splice is guaranteed to be 50% of the compressive strength of the pile.

 

Shaft-grouted RR® micropile

Shaft-grouted RR® micropile and fitted equipment

These piles are mainly shaft-bearing micropiles where the geotechnical bearing capacity of the pile skin is improved through continuous shaft grouting. These are suitable for frictional soils where the high shaft resistance of grouted piles allows using essentially shorter piles.
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Shaft-grouted RR® micropile

Shaft-grouted RR micropile and fitted equipment

These piles are mainly shaft-bearing micropiles where the geotechnical bearing capacity of the pile skin is improved through continuous shaft grouting. These are suitable for frictional soils where the high shaft resistance of grouted piles allows using essentially shorter piles.

Structure:

RR piles are delivered either as pile pipes or as ready-made pile elements with an external sleeve splice at one end of the element.

Collar with grouting holes

The installation of a shaft-grouted RR pile involves feeding grout into the pile from the top which then discharges into the space and soil surrounding the pile through the grouting holes at the lower end. A collar is attached to the lower end of a driven pile to make sufficient room for the grout around the pile. The injection holes are in the lower end of the pile.

Build stronger with high performance RR® and RD® steel piles

Our high-strength RR® and RD® piles, in combination with efficient designing, easy and quick installation, lower environmental impact than traditional piling create a solution that is now stronger than ever.

By using the higher steel grade S550J2H, the piles load-bearing capacity can be added by 25% over that of steel grade S440J2H. The increased load-bearing capacity of the pile can be utilised by using smaller piles or decreasing the number of piles. For the customer, this means a significant improvement in the overall economy of the project.
Learn more
RRs-piles

 

High performance RRs® and RDs® piles

Higher load-bearing capacity and lower costs

RRs pile selection includes seven common pile sizes

The excellent properties of the RR piles, such as splicing easily and quickly with an external friction splice as well as other pile accessories, are utilized also in RRs piles manufactured of high-strength steel.

Advantages of the high-strength steel S550J2H in SSAB's RRs piles:

By using the higher steel grade S550J2H, pile’s load-bearing capacity can be added by 25 % over that of traditional RR piles. The increased load-bearing capacity of the pile can be utilized by decreasing the number of piles.

Alternatively, a RRs pile made of high strength steel can replace a RR pile with bigger size. Good example of this is RRs125/6.3 pile size, which can easily replace pile size RR115/8.

Availability of micropiles: section lengths and pile pipe lengths. For project specific dimensions, please contact our sales.

Mill dimensions of RR and RRs pile sections and pile pipes

Length of pile section (incl. splice)  
Length of pile pipe (excl. splice) 

12 m
 6 m
4 m 3 m
2 m
1.5 m
1.2 m
1.0 m
  6 m
12 m
16 m
 RR75 -
X
O
O
O
O
O
O
  X
O
-
 RR90 - X
O
O
O
O
O
O
  X
O
-
 RR115/6.3 O X
O
O
O
O
O
O
  X
O
O
 RR115/8 O
X
O
O
O
O
O
O
  O
X
O
 RR140/8 X
X
O
O O
O
O
O
  O
X
O
 RR140/10 X
X
O
O
O
O
O
O
  O
X
O
 RR170/10 X
X
O
O
O
O
O
O
  O
X
O
 RR170/12.5 X
O
O
O
O
O
O
O
  O
X
O
 RR220/10 X
O
O
O
-
-
-
-
  O
X
O
 RR220/12.5 X
O
O
O
-
-
-
-
  O
X
O
                   

 
RRs115/8 O
X
O
O
O
O
O
O
  O X
O
RRs125/6.3
X
X
O
O
-
-
-
-
  O
X
-
RRs140/8 X
X
O
O
O
O
O
O
  O
X
O
RRs140/10 X
O
O
O
O
O
O
O
  O
X
O
RRS170/10 X
O
O
O
O
O
O
O
  O
X
O
RRS220/10
X
O
O
O
-
-
-
-
  O
X
O
 X = stock size      O = project-specific size      – = not in production

Mill dimensions of RD and RDs pile sections and pile pipes



Length of pile section with threaded ends 
  1 m
1.2 m
1.5 m
2 m
3 m
4 m
6 m
12 m
RD115/8
O
O
O
O
X
O
O
O
RD140/8
O
O
O
O
O
O
O
O
RD140/10
O
O
O
O
O
O
X
O
RD170/10
O
O
O
O
O
O
X
O
RD170/12.5
O
O
O
O
O
O
X
O
RD220/10
O
O
O
O
O
O
O
O
RD220/12.5
O
O
O
O
O
O
X
O









RDs115/8
O
O
O
O
O
O
O
O
RDs140/8
O
O
O
O
O
O
O
O
RDs140/10
O
O
O
O
O
O
O
O
RDs170/10
O
O
O
O
O
O
O
O
RDs170/12.5
O
O
O
O
O
O
X
O
RDs220/10
O
O
O
O
O
O
O
O
RDs220/12.5
O
O
O
O
O
O
X
O

X = stock size      O = project-specific size      – = not in production

 

 


Length of pile section with threaded splice pieces

6 m 12 m
RD270/10
O
O
RD270/12.5
O
O

X = stock size      O = project-specific size      – = not in production

 



 Lenght of pile pipe without threads
  1 m
1.2 m
 1.5 m
2 m
3 m
4 m
6 m
12 m
12 - 16 m
16 - 34 m
RD90 O O O O O O X - - -
RD115/6.3 O O O O O O X O - -
RD115/8 O O O O O O O X O -
RD140-RD320 O O O O O O O X O O
RDs90 O O O O O O O - - -
RDs100 O O O O O O O - - -
RDs115/6.3 O O O O O O O O - -
RDs115/8 O O O O O O O X O -
RDs125/6.3 O O O O O O O X - -
RDs140-RDs320 O O O O O O O X O -

X = stock size      O = project-specific size      – = not in production

 

 

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