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BS 4466 - Measurement of bending dimensions - 1989

In April 2000 a new British Standard the 'Specification for scheduling, dimensioning, bending and cutting of steel reinforcement for concrete' was introduced; BS 8666 displacing BS 4466, the previous standard described here for reference purposes.

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BS 4466 - Measurement of bending dimensions - 1989
     

  • Preferred Shapes
    		•
         

  • Non-Preferred Shapes
    		•
         

  • BS 4466 Notes
    		•
         

  • Bar Mass Data Table
    		•
         

  • Minimum former radii, bend and hook allowances
    		•


    BS 4466 - Preferred Shapes

    Method of measurement of bending dimensions Total length of bar (L) measured along centre line
    A
    A+h
    A+2h
    A+n

    Where the overall dimension of the bob is critical, use shape code 37.
    A+2n

    Where the overall dimension of either bob is critical, do not use this shape code.
    A+(B)-½r-d

    This formula is approximate. Where r is greater than the minimum value in table 3 BS 4466 1989, use shape code 51.
    A+B+(C)-r-2d
    Method of measurement of bending dimensions Total length of bar (L) measured along centre line
    If angles with the horizontal are 45° or less:

    A+B+(C)

    see note 4.
    If angles with the horizontal are 45° or less:

    A+2B+C+(E)

    see note 4.
    A+(B)-½R-d

    This formula is approximate, if R is minimum, use shape 37. If R is greater than 200mm, see note 2 to clause 10 BS 4466 1989.
    2(A+B)+12d

    Neither A nor B are to be less than 12d or 150mm, whichever is the greater, for grade 460 in sizes not exceeding 20 mm nor less than 14d for sizes of 25mm and over.
      Neither A nor B are to be less than 10d for grade 250 with a minimum value of A and B of 100mm.   See note 3.
    If angle with horizontal is 45° or less.

    A+(C)

    See note 4.
    2A+3B+18d

    If B is greater than 400+2d, see note 2 to clause 10 BS 4466 1989.

    See note 3

    Notes:


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    BS 4466 - Non-Preferred Shapes

    Method of measurement of bending dimensions Total length of bar (L) measured along centre line
    A+0.57B+(C)-1.57d

    If B is greater than 400+2d, see note 2 to clause 10 BS 4466 1989
    If angle with horizontal is 45° or less.

    A+B+C+n

    See note 4.
    If angle with horizontal is 45° or less.

    A+B+(C)-½r-d

    See note 4.
    If angle with horizontal is 45° or less.

    A+B+(C)

    See note 4.
    A+B+C+(D)-1½r-3d
    A+B+C+D+(E)-2r-4d
    A+B+(C)-r-2d
    A+B+C+D+(E)-2r-4d
    A

    These bars will be supplied straight when the radius is greater than that given in table 5 of BS 4466 1989
    Method of measurement of bending dimensions Total length of bar (L) measured along centre line
    2A+B+20d

    See note 3
    2A+B+C+3d

    See note 3
    2A+3B+10d

    Neither A nor B shall be less than 12d or 150mm, whichever is the greater, for grade 460 in sizes not exceeding 20mm not less than 14d for sizes of 25mm and over.
      Neither A nor B are to be less than 10d for grade 250 with a minimum value of A and B of 100mm.     See note 3
    A+B+0.57C+(D)-½r-2.57d

    If C is greater than 400+2d see note 2 to clause 10 BS 4466 1989
    where B is not greater than A/5.

    C⁄B π (A-d) (L<12m)

    Where A is the external diameter of helix (in mm)
    B is the pitch of helix (in mm)
    C is the overall height of helix (in mm).

    Where B is greater than A/5 the formula does not apply.
      There shall be at least two full turns in the helix.
    Note, unless A is small relative to d, this shape is fabricated in a closed form and pulled to shape on site.

    All other shapes

    		 To be calculated

    A dimensional sketch shall be drawn out over schedule columns A to E.

      Every dimension that is to allow for the permissable deviations shall be indicated in parenthesis, otherwise the fabricator is free to choose which dimension shall allow for the tolerance. If a shape that is given in this table or in table 1 BS 4466 1989 is required but a different dimension is to allow for the permissable deviations, the shape code 99 & the free dimension shall be indicated in parenthesis. The tolerances given in table 4 BS 4466 1989 also apply.

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    Notes:
    1. r indicates the minimum value in the table 3 BS 4466 1989
    2. The dimensions in parenthesis are the free dimensions
    3. To avoid separate equations for each steel grade and bending radius, simplified total length formulae are used for shape codes 61, 77, 78, 79 and 82. These formulae are necessarily approximate.
    1. The length formula is approximate and when bending angles exceed 45° the length should be calculated more accurately allowing for the difference between the specified overall dimensions and the true length measured along the central axis of the bar or wire. When the bending angles approach 90°, it is preferable to specify shape code 99 with a fully dimensional sketch.

    BAR MASS per linear metre (kg/m) :-
    50mm: 15.413kg/m 40mm: 9.864kg/m 32mm: 6.313kg/m 25mm: 3.854kg/m 20mm: 2.466kg/m
    16mm:   1.579kg/m 12mm: 0.888kg/m 10mm: 0.616kg/m 8mm: 0.395kg/m 6mm: 0.222kg/m

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    Minimum former radii, bend and hook allowances
    Bar Size Grade 250 bars complying with the requirements of BS 4449 (type and grade R) and BS 6744 type S
    d r † n h
    6†‡ 12 100 100
    8 16 100 100
    10 20 100 100
    12 24 100 110
    16 32 100 150
    20‡ 40 100 180
    25‡ 50 130 230
    32‡ 64 160 290
    40‡ 80 200 360
    50‡ 100 250 450
    Bar Size Grade 460 bars complying with the requirements of BS 4449 (type and grade T) and BS 6744 type S
    d r † n h
    6†‡ 18 100 100
    8 24 100 100
    10 30 100 110
    12 36 100 140
    16 48 100 180
    20‡ 60 110 220
    25‡ 100 180 350
    32‡ 128 230 450
    40‡ 160 280 560
    50‡ 200 350 700
    Fabric Size Sheet Fabric complying with the requirements of BS 4483
    standard size 4.8m x 2.4m
    d r † n h
    5 15 100 100
    6 18 100 100
    7 21 100 100
    8 24 100 100
    9 27 120 135
    10 30 120 135
    12 36 130 145
           
           
           
    **The use of hooks as end anchorages is not normally necessary with deformed bars.

     † It should be borne in mind that special precautions such as reducing the speed of bending or increasing the radius of bending may necessary in cold weather. For bending and rebending on site refer to BS 8110.
     ‡ Non-preferred size for grade 250 bars.
     • Non-preferred size for grade 460 bars.

    NOTE: These radii are the minimum radii of the formers for material complying with the relevant British standard. Certain design situations may call for larger radii and for these the recommendations in BS 8100 should be followed.

    Radius of bending:- maximum values requiring bending
    Bar Size68 1012 1620 2532 40
    Radius (m)2.52.75 3.54.25 7.514 3043 58
    N.B. Bars to be formed to a radius exceeding the above dimensions will be supplied straight.
    see clause 8 BS 4466 1989 for definition of y.

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