Design Aids

Members in Combined Bending and Axial Load

The Reinforced Concrete Design Handbook (RCD) contains column design charts for the design of reinforced concrete sections.

A selected number of charts are included below, but a full range of charts catering for concrete strengths of 20MPa to 60MPa and grade 300 and 450 steel can be obtained by ordering the RCD Handbook.

Reinforcement - Physical Data

 

Cross sectional areas of specific numbers of bars (mm²)
Bar Size (mm)

Numbers of bars

1 2 3 4 5 6 7 8 9 10
6 28.3 57 85 113 141 170 198 226 254 283
10 78.5 157 236 314 393 471 550 628 707 785
12 113.1 226 339 452 565 679 792 905 1018 1131
16 201.1 402 603 804 1005 1206 1407 1608 1810 2011
20 314.2 628 942 1257 1571 1885 2199 2513 2827 3142
24 452.4 905 1357 1810 2262 2714 3167 3619 4071 4524
28 615.7 1231 1847 2463 3079 3694 4310 4926 5542 6157
32 804.2 1608 2413 3217 4021 4825 5630 6434 7238 8042
40 1257 2513 3770 5026 6283 7540 8796 10053 11309 12566

Cross sectional areas of bars at specific spacings (mm²/m width)
Bar Size (mm)

Bar Spacing

75 100 125 150 175 200 225 250 275 300 350 400 450
6 377 283 226 188 162 141 126 113 103 94 81 71 63
10 1047 785 628 524 449 393 349 314 286 262 224 196 175
12 1508 1131 905 754 646 565 503 452 411 377 323 283 251
16 2681 2011 1608 1340 1149 1005 894 804 731 670 574 503 447
20 4189 3142 2513 2094 1795 1571 1396 1257 1142 1047 898 785 698
24 6032 4524 3619 3016 2585 2262 2011 1810 1645 1508 1290 1130 1000
28 8210 6158 4926 4105 3519 3079 2737 2463 2239 2053 1760 1540 1370
32 - 8042 6434 5362 4596 4021 3574 3217 2925 2681 2300 2010 1790
40 - - 10053 8378 7181 6283 5585 5027 4570 4189 3590 3140 2790

Weights of groups of bars (kg per metre run)
Bar Size (mm)

Numbers of bars

1 2 3 4 5 6 7 8 9 10
6 0.222 0.444 0.666 0.888 1.110 1.332 1.554 1.777 1.999 2.221
8 0.395 0.790 1.184 1.579 1.974 2.369 2.763 3.158 3.553 3.948
10 0.617 1.234 1.851 2.467 3.084 3.701 4.318 4.935 5.552 6.169
12 0.888 1.777 2.665 3.553 4.441 5.330 6.218 7.106 7.994 8.883
16 1.579 3.158 4.737 6.317 7.896 9.475 11.054 12.633 14.212 15.791
20 2.467 4.935 7.402 9.870 12.337 14.804 17.272 19.739 22.207 24.674
24 3.553 7.106 10.659 14.212 17.765 21.318 24.871 28.425 31.978 35.531
28 4.836 9.672 14.508 19.344 24.181 29.017 33.853 38.689 43.525 48.361
32 6.317 12.633 18.950 25.266 31.583 37.899 44.216 50.532 56.849 63.166
40 9.870 19.739 29.609 39.479 49.348 59.218 69.087 78.957 88.827 98.696

Weight in kg per square metre for various bar spacings
Bar Size (mm)

Spacing of bars (millimetres)

50 75 100 125 150 175 200 250 300 350
6 4.441 2.961 2.221 1.777 1.480 1.269 1.110 0.888 0.740 0.634
8 7.896 5.264 3.948 3.158 2.632 2.256 1.974 1.579 1.316 1.128
10 12.337 8.225 6.169 4.935 4.112 3.525 3.084 2.467 2.056 1.762
12 17.765 11.844 8.883 7.106 5.922 5.076 4.441 3.553 2.961 2.538
16 31.583 21.055 15.791 12.633 10.528 9.024 7.896 6.317 5.264 4.512
20 49.348 32.899 24.674 19.739 16.449 14.099 12.337 9.870 8.225 7.050
24 71.061 47.374 35.531 28.425 23.687 20.303 17.765 14.212 11.844 10.152
28 - 64.482 48.361 38.689 32.241 27.635 24.181 19.344 16.120 13.817
32 - 84.221 63.166 50.532 42.110 36.095 31.583 25.266 21.055 18.047
40 - - 98.696 78.957 65.798 56.398 49.348 39.479 32.899 28.199

Dimensions of welded square mesh fabric

 

  Main and Cross Wire Welded Fabric (1)
Mesh Type Nominal Pitch Diameter Cross-sectional area Cross-sectional area per metre width Mass per square metre
  mm mm mm² mm² kg
333 M 75 6.30 31.17 409 6.426
334 M 75 6.00 28.27 371 5.829
335 M 75 5.30 22.06 290 4.548
338 M 75 4.00 12.57 165 2.590
661/0 M 150 8.00 50.27 330 5.181
661 M 150 7.50 44.18 290 4.554
662 M 150 7.10 39.59 260 4.081
663 M 150 6.30 31.17 205 3.213
664 M 150 6.00 28.27 186 2.914
665 M 150 5.30 22.06 145 2.274
666 M  150 5.00 19.63 129 2.024
668 M 150 4.00 12.57 82 1.295
6610 M 150 3.15 7.79 51 0.803