Length and size of bars
Price of larger diameter bars
is also lower than of smaller ones. The basic price is that of 16 mm bars, all
larger bars being priced at this rate while smaller bars cost proportionately more
for each 3 mm diameter below 16 mm. But this should be remembered that for
cutting and bending, bars of 25 mm diameter and larger, oxy-acetylene flame or
power operated machine may be used. Bars upto 8 m length can be easily
transported and handled. Bars upto 10 mm diameter can be obtained in long
lengths in coils.
Some common M.S. or Tor Steel
Round bars – Areas, Weights and Perimeters.
Diameter
in mm.
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5
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6
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8
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10
|
12
|
16
|
20
|
22
|
25
|
28
|
32
|
36
|
40
|
45
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Sectional
area in sq. mm.
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20
|
28.3
|
50.3
|
78.6
|
113
|
201
|
314
|
380
|
491
|
616
|
804
|
1018
|
1257
|
1590
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Weight
per meter run in kg.
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0.16
|
0.22
|
0.39
|
0.62
|
0.89
|
1.58
|
2.47
|
2.98
|
3.85
|
4.83
|
6.31
|
7.99
|
9.86
|
12.49
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Perimeter
in mm.
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15.7
|
18.8
|
25.1
|
31.4
|
37.7
|
50.3
|
62.8
|
69.1
|
78.5
|
88.0
|
100.5
|
113.1
|
125.7
|
157.1
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- Note that – Weight of M.S. of Tor Steel Rounds may be found thus –
Standard
weight per meter in kg. = 0.00618 x d2 ; where d = dia.in mm.
- Weight of M.S. Plates. Standard weight per sq. meter = 7.85 x t ; where t is the thickness of plate in mm.
- Weight of 1 cu.m. of M.S. or Tor bar = 7850 kg.
- Weight of one bag of cement = 50 kg.
- Volume of one bar of cement = 0.0347 cu.m.
- Thus the density of steel may be taken as 78.5 quintal per cu.m. or 7.85 grams per cu.cm.
- To produce 1 cu.m. of wet volume of concrete 1.54 cu.m. of dry volume should be considered.
Cost Ratio (C.R.) for steel and
concrete
The ratio between the cost of
two parts or components involved in a work is known as Cost Ratio, shortly
termed as C.R. Rate of steel per.cu.m. is taken as 62.5 times the cost of
concrete as prevailing in India. So, cost ratio or C.R. for steel and concrete
is Cost of steel per M3 / Cost of concrete per M3 = 62.5
Weight of 1 cu.m. steel (Tor or
plain) = 7850kg. Cost@8.40 per kg = Rs.65940
Cost of 1 cu.m. of concrete M15
(1:2:4) for R.C.C. work = Rs. 1050
Therefore, Cost Ratio for steel
and concrete = Rs.65940/Rs.1050 = 62.8
