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RR® and RD® micropiles

Micropiles offer an effective and convenient way to implement the piling

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

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

    The selection of a suitable micropile type should be based primarily on soil conditions, but superstructures and ambient structures also play a major role.

     

    Applications:

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

    Micropile installation

    RR® micropiles can be installed using light basic equipment (<20 to 25 t) up to a size of about RR170. They can be installed by impact driving or jacking. A heavy hammer may be advantageous when driving RR® micropiles into dense soil, but it also increases the risk of bending. Pile cushions are usually not needed. If a micropile cushion is not used, a dolly made of a thick steel plate is used between the hammer and the pile. The head of the micropile is adjusted inside the lower part of the helmet to ensure that the impact is transmitted centrically.

    RD® micropile installation can be done in all soil conditions. They may be drilled through all natural soil layers all the way into bedrock, with small deviations in position and inclination. In very exacting conditions, such as those involving thick fill layers containing large boulders, the smallest diameter micropiles may pose a slightly higher risk of bending in comparison to large diameter micropiles.

    For more information regarding RR® and RD® micropile installation, see SSAB’s RR® and RD® piles design and installation manual.

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    RR® and RD® piles design and installation manual

    Micropile design

    Micropile design requires that micropile foundations are always designed together withthe structures to be supported on it, which allows selecting the most suitable shape, dimensionsand stiffness for the entire structure.

    The RR® micropiles are delivered either as pipes or as ready-made elements with an external sleeve splice at one end of the element. They are designed to offer quick and cost-effective splicing, minor displacement of soil, minor vibration disturbance and high installation strength.

    The RD® micropiles are delivered as pipes when splicing is done by welding. Another option is threaded RDT splices in which case the piles are delivered as ready-made elements with both ends threaded and with external threaded sleeves.

    An RDT micropile comprises:

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

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

    RRPileCalc is a design program for SSAB's steel micropiles. Eurocodes as well as National codes and instructions are applied in the end-bearing micropile design. See the Design Tools section below for more information.

    RR® micropile

    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.

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    RD® micropiles

    Drilled micropiles for drilling in difficult ground conditions

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

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    Shaft-grouted RR® micropile

    Shaft-grouted RR® micropile and fitted equipment

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

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    Availability

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

    RR® pile

    Mill dimensions of RR (S460MH) and RRs (S550J2H) pile sections and pile pipes

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

    Length of pile section (incl. splice)
    Length of pile pipe (excl. splice)
    Pile
    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
    RR245/10
    O
    O
    O
         		- - - - - -
    O
    O
    O
    RR245/12.5
    X
    O
    O
         		- - - - - -
    O
    X
    O
    RR270/10
    O
    O
    O
         		- - - - - -
    O
    O
    O
    RR270/12.5
    X
    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
    RRs170/12.5
    X
    O
    O
    O
    O
    O
    O
    O
         		-
    O
    X
    O
    RRs220/10
    X
    O
    O
    O
         		- - - - -
    O
    X
    O
    RRs220/12.5
    X
    O
    O
    O
         		- - - - -
    O
    X
    O
    RRs245/10
    O
    O
    O
         		- - - - - -
    O
    O
    O
    RRs245/12.5
    O
    O
    O
         		- - - - - -
    O
    O
    O
    RRS270/10
    O
    O
    O
         		- - - - - -
    O
    O
    O
    RRS270/12.5
    O
    O
    O
         		- - - - - -
    O
    O
    O