What Is Bar Bending Schedule | Preparation as Per Bs 4466 | Tolerances as Per Bs 4466

What Is Bar Bending Schedule?

Why Calculating of Bar Schedule?

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  • A requirement of steel in the project
  • Labor cost
  • Project monitoring
  • Material reconciliation
  • Contol of Wastage in steel etc..
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Preparation of Bar Bending Schedule as Per Bs 4466

  • Form of Schedule as Per Bs 4466
  • Form of Fabric Schedule
  • Preferred Shapes, Their Method of Calculation and Measurement of the Length
  • Other Shapes, Their Method of Calculation and Measurement of the Length
  • Minimum Former Radii, Book and Bend Allowances
  • Scheduling 
  • Bends and Hooks
  • Tolerances on Cutting and Bending Dimensions
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Form of Schedule as Per BS 4466

  • Form of Fabric Schedule as Per BS 4466

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  • Preferred Shapes, Their Method of Calculation and Measurement of the Length

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Shape codeMethod of measurement of bending dimensionsTotal length of bar (L) measured along centreline
20A
32A + h
33A + 2h
34A + nWhere the overall dimension of the bob is critical, use shape code 37
35A + 2nWhere the overall dimension of either bob is critical, do not use this shape code
37A + (B) –½r–dThis formula is approximate Where r is greater than the minimum value inTable 3 use shape code 51
38A + B + (C) –r –2d
41If angle with the horizontal are 45° or less,A + B + (C)length formula is near about and when bending angles exceed 45 ° the length could be calculated more accurately allowing for this difference between the specified overall the true length and dimensions measured along the central axis of this bar or wire.
43If angle with the horizontal are 45° or less,A + 2B + C + (E)length formula is near about and when bending angles exceed 45 ° the length could be calculated more accurately allowing for this difference between the specified overall the true length and dimensions measured along the central axis of this bar or wire.
51A + (B) –1/2R – dThis formula is approximate R is minimum, use shape code 37If R is greater than 200 mm
612(A + B)+ 12dNeither A nor B are to be less than 12d or 150 mm, whichever is the greater, for grade 460 in size not exceeding 20 mm nor less than 14d for size of 25 mm and over Neither A nor B are to be less than 10d for grade250 with a minimum value of A and B of 100 mm
62If angle with the horizontal is 45° or less,A + (C)
82length formula is near about and when bending angles exceed 45 ° the length could be calculated more accurately allowing for this difference between the specified overall the true length and dimensions measured along the central axis of this bar or wire.2A + 3B + 18dIf B is greater than 400 + 2 d
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  • Other Shapes, Their Method of Calculation and Measurement of the Length

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Shape codeMethod of measurement of bending dimensionsTotal length of bar (L) measured along centreline
39A + 0.57B + (C) –1.57dIf B is greater than400 + 2d, If B is greater than 400 + 2d
42If the angle with horizontal is 45° or less, A + B + C + n
45If the angle with horizontal is 45° or less A + B + (C) –1/2r –d
49If the angle with horizontal is 45° or less, A + B + (C)
52A + B + C + (D) –11/2r–3d
53A + B + C + D + (E) –2r –4d
54A + B + (C) - r + 2d
55A + B + C + D + (E) - 2r - 4d
65A
772A + B + 20d
782A + B + C +3d
792A + 3B + 10d : Neither A nor B aren't to be more than 12dor150mm, whichever is the greater, for grade460in sizes not exceeding 20 mm more than 14d for sizes of 25 mm and over. Neither A nor B aren't to be more than 10d for grade250 with a minimum value of A and Bof100mm
85A + B + 0.57 C + (D) – 1/2r –2.57d IfCisgreaterthan 400 + 2d
87Where B is not greater than A/5 (C/B)π(A-d) (L≤12m) where A is the external dia (in mm)B is the pitch in helix (in mm)C is the overall height in helix (in mm)there B is greater than A/5 the formula doesn't apply. There may be at least two full turns in the helix.
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  • Minimum Former Radii, Book and Bend Allowances

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Bar sizeGrade and Type  R and type and grade SGrade and Type  T and type and grade SFabric complying from BS 4483
drnhrnhdrnh
6a1210010018100100515100100
81610010024100100618100100
102010010030100110721100100
122410011036100140824100100
163210015048100180927120135
2040100180601102201030120135
25501302301001803501236130145
3264160290128230450
4080200360160280560
50a100250450200350700
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Scheduling

  • Each sheet or bar of fabric should be scheduled completely and without any reference to earlier schedules. Such as descriptions  “See schedule 12” or “As before” shall not be used
  • The preferred shape codes to be used shall be as given in Table 1. Table 2 gives other shape codes that may be required. Shapes that do not have a specific shape code number given in Table 1 or Table 2
  • For shapes without an end anchorage, thedimension shown in parentheses in Table 1 and Table 2 shall be the variable dimension to allow for the permissible deviations
  • No dimension given in Table 1 or Table 2 shall be given a zero value, as this changes the basic shape.
  • If the angle between both portions of the shaped meeting at a bend isn't a right angle, it should be given and shall be defined by co-ordinates and not by degrees of arc.
  • The overall off-set dimension of a crank should be not less than twice the size of the bar or wire.
  • The angled length as shown in Figure 6 shall be not less than 10d for grade 250 nor less than 12d for grade 460 in sizes of less than 20 mm nor less than 14d for grade 460 in sizes of 25 mm and over.
  • Or all shapes with two or more bends into the same or opposite directions, the overall dimension is given on the schedule shall always include a minimum straight of 4d between the curved portion of the bends, as shown in as per the below figure. The value of x in as per below figure  shall be not less than the following:
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Example of a bar with minimum than one bendRead more10 dRead more250 Read more12 d Read more14 d Read more460Read more
  • The minimum length of material to be given on this schedule to form a hook or bend shall be as given for n or h respectively inTable 3.
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Bends and Hooks

  • Before taking into account the cumulative cutting tolerances, the nominal value for in table 3 shall be calculated as follows:
    • For a bend, n – 0.57r+ 0.21d;
    • For a hook, h–2.14r– 0.57d
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Tolerances on Cutting and Bending Dimensions

  • The tolerances given in Table 4 shall apply for cutting and/or bending dimensions and should be taken in the account then completing the schedule. The end anchorage or the dimension in parentheses into the shape codes given inTable 1 and Table 2 shall be used to allow for any permissible deviations resulting from cutting and bending.
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DescriptionTolerance in mm
Cutting of straight lengths (including reinforcement for+ 25
Subsequent bending)— 25
Bending < 1 000+5 up to -5
> 1 000 mm to < 2 000 mm+5 up to -10
> 2 000 mm+5 up to -25
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Radius of Bending in Reinforcement

  • Reinforcement to be formed into a radius exceeding that given in Table 5 shall be supplied straight.
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Bar size (mm)6810121620253240
Wire size (mm)567891012
Radius (m)2.42.52.62.83.03.54.37.514.030.043.058.0
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