UNIVERSITY OF ADEN

FACULATY OF ENGINIREEING
CIVIL ENGINEERING DEPARTMENT

Design table for reinforcement concrete element

Abstracted from British Standard
Code of Practice For Design & construction
BS 8110 : Part 1 ,1997

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 Table 1 Bar Reinforcement: Cross Sectional Areas(mm2) Of Specific
Numbers Of Bars And Perimeters
Diameter or Number of Bars Perimeter
Nominal (mm)
size(mm) 1 2 3 4 5 6 7 8 9 10

6 28 57 85 113 142 170 198 226 255 283 18.9

8 50 101 151 201 252 302 352 402 453 503 25.1

10 78 157 236 314 393 471 550 628 707 785 31.4

12 113 226 339 452 566 679 792 905 1020 1130 37.7

14 154 308 462 616 770 924 1077 1231 1385 1539 43.9

16 201 402 603 804 1010 1210 1410 1610 1810 2010 50.3

18 254 509 763 1018 1272 1527 1781 2036 2290 2544 56.5

20 314 628 943 1256 1570 1890 2200 2510 2830 3140 62.8

22 380 760 1140 1520 1900 2281 2661 3041 3421 3801 69.1

25 491 982 1470 1960 2450 2950 3440 3930 4420 4910 78.5

Table 2: Bar Reinforcement: Cross Sectional Areas Of Bars (mm2 per meter width)
At specified Spacing.
Diameter or Spacing of Bars (mm)
Nominal
75 100 120 125 150 175 200 225 250 275 300
size(mm)
6 377 283 236 226 189 162 142 126 113 103 94

8 671 503 419 402 335 287 252 224 201 183 168

10 1050 785 654 628 523 449 393 349 314 285 262

12 1510 1130 924 905 754 646 566 502 425 411 377

14 2050 1539 1280 1230 1025 880 770 680 615 560 510

16 2680 2010 1675 1610 1340 1150 1010 893 804 731 670

18 3390 2540 2120 2035 1695 1450 1270 1130 1015 925 845

20 4190 3140 2618 2510 2040 1800 1570 1396 1260 1142 1050

22 5065 3800 3165 3040 2530 2170 1900 1685 1520 1380 1265

25 6550 4190 4091 3930 3270 2810 2450 2182 1960 1785 1640

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Table 3 Typical Imposed Loads And Weights Of Materials

Roof And Roof Imposed Loads:-

kN/m2
Flat roof , no access 0.75
Flat roof , with access 1.50
Residential premises:
Hoses with normal furniture 1.50
Hotels , motels and hospitals 2.00
Hostels in schools and colleges 1.50
Place of public assembly:
Class-room and laboratories 3.00
Public halls, theatres and cinemas 4.00
Library reading rooms with book storage 4.00
Shops (display and sale) 4.00
Stores and libraries 6.00

Weights:- kN/m2
Floor les 2.5 cm thick 0.65
Hollow concrete block,10 cm thick 1.30
Hollow concrete block,15 cm thick 2.00
Hollow concrete block,20 cm thick 2.60
Plain concrete block,10 cm thick 2.00
Plain concrete block,15 cm thick 3.00
Plain concrete block,20 cm thick 4.00

kN/m3
Cement 13.00
Cement mortar 16.50
Cement plaster 16.50
Tiles 24.00
Stone wall 23.00
Plain concrete 23.00
Reinforced concrete 24.00
Marbles 27.50
Sand layer 17.50

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 Table 4 : Design Table For Singly Reinforcement sections

fcu 20 25 30 35 40 45 50
Ky 9.411 11.763 14.116 16.468 18.821 21.174 23.526
kz 19.812 24.765 29.717 34.670 39.623 44.576 49.529
2
Max. value of M/bd 3.12 3.9 4.68 5.46 6.24 7.02 7.8
2
Limiting value of M/bd
0.848 1.06 1.273 1.485 1.697 1.909 2.12
(z=0.95 d)
If M/bd2 ranges between the limiting and maximum value, than If M/bd2 is less than or equal to the limiting value, then

Table 5: Design Table For Doubly Reinforcement Sections

x/d Fcu 20 25 30 35 40 45 50
Ko 2.088 2.610 3.132 3.654 4.176 4.698 5.220
0.3
kp 3.176 3.176 3.811 4.446 5.082 5.717 6.352
Ko 2.639 3.299 3.959 4.618 5.278 5.938 6.598
0.4
kp 3.388 4.235 5.082 5.929 6.776 7.623 8.469
Ko 3.118 3.897 4.677 5.456 6.236 7.015 7.795
0.5
kp 4.235 5.293 6.352 7.411 8.469 9.528 10.587
x/d 0.3 0.4 0.5
Max. value 0.3 ‫( ـــ‬fy/2456) 0.4 ‫( ـــ‬fy/1842) 0.5 ‫( ـــ‬fy/1473)
of d'/d

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 Table 3.25 Minimum Percentages Of Reinforcement
Situation Definition of Minimum percentage
percentage fy = 250 N/mm2 fy = 250 N/mm2
Tension reinforcement % %
Sections subjected mainly to pure tension 100 As / Ac 0.80 0.45
Sections subjected to flexure:
a) flanged beams, web in tension:
1) bw/b < 0.4 100 As/bw h 0.32 0.18
2) bw/b
0.4 100 As/bw h 0.24 0.13

b) flanged beams, flange in tension:

1) T-beam 100As/bwh 0.48 0.26
2) L-beam 100 As/bwh 0.36 0.20

c) rectangular section (in solid slabs this minimum

100 As / Ac 0.24 0.13
should be provided in both directions)

Compression reinforcement:(where such

reinforcement is required for the ultimate limit
state)
General rule 100Asc/Acc 0.40 0.40

Simplified rules for particular cases:

a) rectangular column or wall 100Asc /Acc 0.40 0.40

b) flanged beam:
1) flange in compression 100Asc /b hf 0.40 0.40
2) web in compression 100Asc /bwh 0.20 0.20

c) rectangular beam 100 Asc /Ac 0.20 0.20

Transverse reinforcement in flanges or flanged

beams (provided over full effective flange width 100Ast / hf l 0.15 0.15
near top surface resist horizontal shear)

Where:
Ac :Total area of concrete.
Acc :Area of concrete in compression .
As :Minimum recommended area of reinforcement.
Asc :Area of steel in compression.
Ast :Area of transverse steel in flange.
b :Breadth of the section.
bw :Breadth or effective breadth of the rib; for a box, T or L section.
bw is taken as the average breadth of concrete below the flange.
h :Overall depth of the cross section of a reinforcement member.
Hf :Depth of flange
l :Span of the beam

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Table 3.9 - Basic span/effective depth ratio for rectangular or flanged beams

Support conditions Rectangular section Flanged beams with

bw / b= 1 bw / b≤ 0.3
Cantilever 7 5.6

Simply supported 20 16.0

Continuous 26 20.8

The basic span/effec ve depth ra os for beams are given in Table 3.9 are based on limi ng the total deflec on to
span/250 and this should normally ensure that the part of the deflec on occurring a er construc on of finishes
and par ons will be limited to span / 500 or 20mm, whichever is the lesser, for spans up to 10m. For values of
bw/b greater than 0.3, linear interpola on between the values given in Table 3.9 for rectangular sec ons and for
flanged beams with bw / b of 0.3 may be used.

Table 3.10: Modifica on factor for tension reinforcement

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Table 3.11 — Modification factor for compression reinforcement
100 A's prov./bd Factor
0.00 1.00
0.15 1.05
0.25 1.08
0.35 1.10
0.50 1.14
0.75 1.20
1.0 1.25
1.5 1.33
2.0 1.40
2.5 1.45
≥
3.0 1.50
NOTE 1: The values in this table are derived from the following equation:

NOTE 2: The area of compression reinforcement A used in this table may include all bars in the compression
zone, even those not effectively tied with links.

Table 3.7 — Form and area of shear reinforcement in beams

Table 3.16 — Form and area of shear reinforcement in solid slabs

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 Table 3.8 — Values of vc design concrete shear stress

Table 3.5 — Design ultimate bending moments and shear forces

Table 3.5 may be used to calculate the design ul mate bending moments and shear forces, subject to the following provisions:
a) characteristic imposed load Qk may not exceed characteristic dead load Gk;
b) loads should be substantially uniformly distributed over three or more spans;
c) varia ons in span length should not exceed15% of longest.

Table 3.12 — Ultimate bending moment and shear forces in one-way spanning slabs
(approximately equal span) varia ons in span length should not exceed15% of longest

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Table 3.14 — Bending moment coefficients for rectangular panels supported
on four sides with provision for torsion at corners

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Table 3.15- Shear force coefficient for uniformly loaded rectangular panels
supported on four sides with provision for torsion at corners

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