Course · lesson 2 of 6

SANS 282 shape codes and cutting lengths

Every bent bar on a schedule is a shape code and a set of legs. This lesson goes through the SANS 282:2011 shapes STATIX uses, the bend radius for R and Y bars, the Table 1 lengths, rounding, large radii and custom shapes, and the changes since the 2004 edition.

1. Learning outcomes

After this lesson you can:

choose the right SANS 282:2011 shape code and give its legs;
use the standard bend radius and allowances for R and Y bars;
work out cutting lengths by Table 1 and round them;
schedule a bar with a large radius, or a custom shape;
recognise codes from older drawings and schedules.

2. Before you start

Lesson 1 (reading drawings and schedules) and RC Design 1, lesson 8.
Your copy of SANS 282, and the project schedule.
A pocket calculator and about 45 minutes.

3. The shapes

The SANS 282:2011 shapes STATIX schedules: 20 straight, 37 one bend (and 037, mirrored), 38 the U or channel, 038 the crank, 41 the bent-up crank, 51 one large-radius bend, 60 the closed link, and 99 any other shape with a dimensioned sketch (65, a bar curved to a radius, is also catalogued). The letters are the legs the schedule gives.

Shape 37 and its mirror 037: one 90° bend, leg A up from the corner and B along. In the 2011 edition each leg must be at least ten bar diameters; the STATIX catalogue flags a shorter leg.

Shape 38 is the U (both end legs on the same side of the long leg B); shape 038 is the crank, a long leg, a short riser and a return. They share the length formula. Older drawings called the U-bar 35 and the crank 38: in SANS 282:2011, 35 no longer exists and 38 is the U.

Shape 41, the bent-up crank: a bottom run, a sloping leg and a top run, with D the rise. B is the true length of the slope, and Table 1 adds the three runs with no deduction.

Shape 60, the closed link. A is the vertical side and B the horizontal one, both outside dimensions; the two hooks are covered by the tabulated hook allowance N (100 mm for Y6 to Y12, 120 for Y16). Table 1: 2A + 2B + 2N − 1.5r − 3d.

Bigger radii and other shapes. An L-bar that must be bent round a larger radius (some wall and corbel bars) becomes shape 51, with the radius E on the schedule. Any shape the table does not cover, or another shape with a non-standard radius, is scheduled as 99 with a dimensioned sketch.

4. Radius, dimensions and length

The standard former radius, SANS 282 Figures 2 and 3: twice the bar size for mild steel (R) and three times for high yield steel (Y), at every size. The same tables give the hook and bend allowances (h and N). A bar is always bent round at least this radius.

Why lengths are less than the sum of the letters. The legs are given to the outside of the bar (cl. 4.1.1), but the bar cuts the corner round its radius. SANS 282 Table 1 gives the exact length for each shape; for one 90° bend it is A + B − r/2 − d.

20: A 37: A + B − r/2 − d 38, 038: A + B + C − r − 2d 41: A + B + C (B the true slope) 51: A + B − 0.43E − 1.21d 60: 2A + 2B + 2N − 1.5r − 3d r: R 2d, Y 3d (Figures 2, 3); N: hook allowance (Figures 2, 3)

5. Rounding and editions

Rounding. The calculated length is always rounded up to the next 50 mm, so a bar is never cut short; the leg dimensions are given to 5 mm. The catalogue caps a bar at 13 000 mm.

Editions. Some codes and limits changed between SANS 282:2004 and 2011: shape 35 was dropped, the 99 custom series was re-lettered, and minimum leg lengths moved. A schedule should state its edition; STATIX schedules to 2011.

6. In STATIX

In STATIX the project schedule, the project board and the calc sheets work from the SANS 282:2011 catalogue: you give the shape code and the legs, and the length comes from Table 1 with the standard radius for the bar type, rounded up to 50 mm.