Design aids for determining flexural reinforcement
All links to tables referred to in the flow
chart:
Procedure for determining flexural reinforcement
Table 4 - Values for K'
| % redistribution |
δ (redistribution
ratio) |
K' |
| 0 |
1.00 |
0.205 |
| 5 |
0.95 |
0.193 |
| 10 |
0.90 |
0.180 |
| 15 |
0.85 |
0.166 |
| 20 |
0.80 |
0.151 |
| 25 |
0.75 |
0.136 |
Table 5 - z/d for singly reinforced sections
| K |
z/d |
K |
z/d |
| 0.01 |
0.950a |
0.11 |
0.891 |
| 0.02 |
0.950a |
0.12 |
0.880 |
| 0.03 |
0.950a |
0.13 |
0.868 |
| 0.04 |
0.950a |
0.14 |
0.856 |
| 0.05 |
0.954 |
0.15 |
0.843 |
| 0.06 |
0.944 |
0.16 |
0.830 |
| 0.07 |
0.934 |
0.17 |
0.816 |
| 0.08 |
0.924 |
0.18 |
0.802 |
| 0.09 |
0.913 |
0.19 |
0.787 |
| 0.10 |
0.902 |
0.20 |
0.771 |
| Keya Limiting z to
0.95d is not a requirement of Eurocode 2, but considered
to be good practice. |
Table 6 - Minimum percentage of required reinforcement
| fck |
fctm |
Minimum percentage (0.26
fctm / fyka |
| 25 |
2.6 |
0.13% |
| 28 |
2.8 |
0.14% |
| 30 |
2.9 |
0.15% |
| 32 |
3.0 |
0.16% |
| 35 |
3.2 |
0.17% |
| 40 |
3.5 |
0.18% |
| 45 |
3.8 |
0.20% |
| 50 |
4.1 |
0.21% |
| Keya Assuming fyk
= 500MPa |
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