Precon Products, A leading national independent supplier of construction products

You currently have 0 items in your enquiry

Bending Dimensions - Preferred Shapes

Shape Code Method of Measurement Code of Bending Dimensions Total Length of the Bar (L) Mm Measured Along Centreline
00 A
01 AStock bars are supplied in 12 metre notional lengths in diameters of 12 mm and above in original manufacturers bundles. Tolerances for stock lengths shall be subject to BS4449: 2005
11 A+(B)-0.5r-dNeither A nor B shall be less than P in Table 2
12 A+(B)-0.45R-1.2dNeither A nor B shall be less than P in Table 2 nor less than (R + 6d)
13 A+0.57B + (C) - 1.6dB shall not be less than 2(r + d). Neither A nor C shall be less than P in Table 2 nor less than (B/2 + 5d). See Note 3. Key: 1 - Semi-circular
14 A + (C) - 4dNeither A nor (C) shall be less than P in Table 2.See note 1.
15 A + (C)Neither A nor (C) shall be less than P in Table 2.See note 1.
21 A + B + (C) - r - 2dNeither A nor (C) shall be less than P in Table 2.
22 A+B+C+(D)-1.5r-3dC shall not be less than 2 (r + d). Neither A nor (D) shall be less than P in Table 2. (D) shall not be less than (C/2 + 5d).Key: 1 - Semi-circular BS4449: 2005
23 A + B + (C) - r - 2dNeither A nor (C) shall be less than P in Table 2.
24 A + B + (C)A and (C) are at 90° to one another.
25 A + B + (E)Neither A nor B shall be less than P in Table 2. If E is the critical dimension, schedule a 99 and specify A or B as the free dimension.See note 1.
26 A + B + (C)Neither A nor (C) shall be less than P in Table 2.See note 1.
27 A + B + (C) - 0.5r - dNeither A nor (C) shall be less than P in Table 2.See note 1.
28 A + B + (C ) -0.5r - dNeither A nor (C) shall be less than P in Table 2.See note 1.
29 A + B + (C ) -r - 2dNeither A nor (C) shall be less than P in Table 2.See note 1.
31 A+B+C+(D)-1.5r-3dNeither A nor (D) shall be less than P in Table 2.
32 A+B+C+(D)-1.5r-3dNeither A nor (D) shall be less than P in Table 2.See note 1.
33 2A+1.7B+2(C)-4dA shall not be less than 12d + 30mm. B shall not be less than 2(r + d). (C) shall not be less than P in Table 2, nor less than (B/2 + 5d.) See note 3. Key: 1 - Semi-circular
34 A+B+C+(E)-0.5r-dNeither A nor (E) shall be less than P in Table 2.See note 1.
35 A+B+C+(E)-0.5r-dNeither A nor (E) shall be less than P in Table 2.See note 1.
36 A+B+C+(D)-r-2dNeither A nor (D) shall be less than P in Table 2.See note 1.
41 A+B+C+D+(E)-2r-4dNeither A nor (E) shall be less than P in Table 2.See note 1.
44 A+B+C+D+(E)-2r-4dNeither A nor (E) shall be less than P in Table 2.See note 1.
46 A+2B+C+(E)Neither A nor (E) shall be less than P in Table 2.See note 1.
47 2A+B+2C+1.5r-3d(C) and (D) shall be equal and not more than A nor less than P in Table 2. Where (C) and (D) are to be minimised the following formula may be used: L = 2A + B + max (21d, 240)
51 2(A+B+(C)-2.5r-5d(C) and (D) shall be equal and not more than A or B nor less than P in Table 2. Where (C) and (D) are to be minimised the following formula may be used: L = 2A + 2B + max (16d, 160)
56 A+B+C+(D)+2(E)-2.5r - 5d(E) & (F) shall be equal and not more than B or C, nor less than P in Table 2See note 1.
63 2A+3B+2(C)-3r-6d(C) and (D) shall be equal and not more than A or B nor less than P in Table 2. Where (C) and (D) are to be minimised the following formula may be used: L = 2A + 3B + max (14d, 150)
64 A+B+C+2D+E+(F)-3r-6dNeither A nor (F) shall be less than P in Table 2.See note 2.
67 ASee clause 10
75 3 (A - d) + BWhere B is the overlap.
77 C3 (A - d)Where B is greater than A/5 this equation no longer applies, in which case the following formula may be used:
L = C (F(A - d))2 + B2)0.5
C = Number of turns
98 A+2B+C+(D)-2r-4dIsometric stetch.Neither C nor (D) shall be less than P in table 2.

The values for minimum radius and end projection, r and P respectively, as specified in Table 2, shall apply to all shape codes (see 7.6).

The dimensions in parenthesis are the free dimensions. If a shape given in this table is required but a different dimension is to allow for the possible deviations, the shape shall be drawn out and given the shape code 99 and the free dimension shall be indicated in parenthesis.

The length of straight between two bends shall be at least 4d, see figure 6. Figures 4, 5 and 6 should be used in the interpretation of bending dimensions.

NOTE 1:

The length equations for shape codes 14, 15, 25, 26, 27, 28, 29, 34, 35, 36 and 46 are approximate and where the bend angle is greater than 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. When the bending angles approach 90°, it is prefer- able to specify shape code 99 with a fully dimensional sketch.

NOTE 2:

Five bends or more might be impractical within permitted tolerances.

NOTE 3:

For shapes with straight and curved lengths (e.g. shape codes 12, 13, 22, 33 and 47) the largest practical mandrel size for the production of a continuous curve is 400mm. See also Clause 10.

Tolerances On Cutting And Bending Dimensions

The tolerances for cutting and/or bending dimensions shall be in accordance with Table 5 and shall be taken into account when completing the schedule. The end anchorage or the dimension in parethesis in the shape codes shall be used to allow for any permissible deviations resulting from cutting and bending.

Table 5

Tolerances
Cutting and bending processes Tolerance (mm)
Cutting of straight lengths (including reinforcement for subsequent bending) +25, -25
Bending
< 1000mm > 1000mm to < 2000mm > 2000mm
+5, -5
+5, -10
+5, -25
Length of bars in fabric 25 or 0.5% of the length (whichever is greater)

Example of a bar with more than one bend

Dimensioning of cranked bars

Minimum schedule radius and bend allowances

Table 2

Normal Bar Size d (mm) Minimum Radius for scheduling R (mm) Minimum Diameter of Bending Former (mm) Minimum end projection P
General (min 5d straight) (mm) Links where bend <150° (mm)
6 12 24 110 10
8 16 32 115 115
10 20 40 120 130
12 24 48 125 160
16 32 64 130 210
20 70 140 190 290
25 87 175 240 365
32 112 224 305 465
40 140 280 380 580
50 175 350 475 72

Radius of bending

Reinforcement to be formed to a radius exceeding that specified in Table 6 shall be supplied straight.

Table 6

Maximum limit for which a performed radius is required
Bar Size (mm) Radius (m)
6 2.5
8 2.75
10 3.5
12 4.25
16 7.5
20 14.0
25 30.0
32 43.0
40 58.0

NOTE 1

The required curvature may be obtained during placing.

NOTE 2

For shapes with straight and curved lengths (e.g. shape code 12, 13, 22 and 33) the largest practical radius for the production of a continuous curve is 200mm, and for larger radii the curve may be produced by a series of short straight sections.