Unit conversions and Calculations in Civil engineering

While dealing with various problems in civil engineering we often come across a lot of units. Standard values given by IS codes play a significant role in civil engineering practice. We need to remember some basic things out of these. In this post, some of these basic things are going to be discussed.

CONCRETE GRADES:

M5 = 1:4:8
M10= 1:3:6
M15= 1:2:4
M20=  1:1.5:3
M25= 1:1:2

CLEAR COVER TO MAIN REINFORCEMENT:


1.FOOTINGS: 50 mm
2.RAFT  FOUNDATION.TOP: 50 mm
3.RAFT FOUNDATION.BOTTOM/SIDES: 75 mm
4.STRAP BEAM: 50 mm
5.GRADE SLAB: 20 mm
6.COLUMN: 40 mm
7.SHEAR WALL: 25  mm
8.BEAMS: 25 mm
9.SLABS: 15 mm
10.FLAT SLAB: 20 mm
11.STAIRCASE: 15 mm
12.RET. WALL: 20/ 25 mm on earth
13.WATER RETAINING STRUCTURES:  20/30 mm

WEIGHT OF ROD PER METER LENGTH:


DIA WEIGHT PER METER
6mm = 0.222Kg
8mm = 0.395 Kg
10mm = 0.616 Kg
12mm = 0.888  Kg
16mm = 1.578 Kg
20mm = 2.466 Kg
25mm = 3.853 Kg
32mm = 6.313  Kg
40mm = 9.865 Kg

1bag cement-50kg
1feet-0.3048m
1m-3.28ft
1sq.m-10.76sq.f t
1cu.m-35.28cu.ft
1acre-43560sq.ft
1hectare-2.47acre


DESIGN MIX:


M10 ( 1 : 3.92 : 5.62)

Cement : 210 Kg/ M 3
20  mm Jelly : 708 Kg/ M 3
12.5 mm Jelly : 472 Kg/ M 3
River sand : 823 Kg/ M  3
Total water : 185 Kg/ M 3
Fresh concrete density: 2398 Kg/M 3

M20 ( 1 : 2.48 :  3.55)

Cement : 320 Kg/ M 3
20 mm Jelly : 683 Kg/ M 3
12.5 mm Jelly :  455 Kg/ M 3
River sand : 794 Kg/ M 3
Total water : 176 Kg/ M  3
Admixture : 0.7%
Fresh concrete density: 2430 Kg/ M 3

M25 ( 1 : 2.28 :  3.27)

Cement : 340 Kg/ M 3
20 mm Jelly : 667 Kg/ M 3
12.5 mm Jelly :  445 Kg/ M 3
River sand : 775 Kg/ M 3
Total water : 185 Kg/ M  3
Admixture : 0.6%
Fresh concrete density: 2414 Kg/ M 3
Note: sand 775  + 2% moisture, Water185 -20.5 =
164 Liters,
Admixture = 0.5% is  100ml

M30 ( 1 : 2 : 2.87)


Cement : 380 Kg/ M 3
20 mm Jelly : 654 Kg/ M  3
12.5 mm Jelly : 436 Kg/ M 3
River sand : 760 Kg/ M 3
Total water :  187 Kg/ M 3
Admixture : 0.7%
Fresh concrete density: 2420 Kg/ M 3
Note:  Sand = 760 Kg with 2% moisture
(170.80+15.20)

STANDARD CONVERSION FACTORS


INCH = 25.4 MILLIMETRE
FOOT =  0.3048 METRE
YARD = 0.9144 METRE
MILE = 1.6093 KILOMETER
ACRE = 0.4047  HECTARE
POUND = 0.4536 KILOGRAM
DEGREE FARENHEIT X 5/9 – 32 =  DEGREE
CELSIUS
MILLIMETRE= 0.0394 INCH
METRE = 3.2808FOOT
METRE =  1.0936YARD

MATERIAL CALCULATION:

CEMENT IN BAGS

01. PCC 1:5:10 1440/5*0.45 129.60Kg 2.59
02. PCC 1:4:8(M 7.5)  1440/4*0.45 162.00Kg 3.24
03. PCC 1:2:4(M 15) 1440/2*0.45 324.00Kg  6.48
04. PCC 1:3:6(M 10) 1440/3*0.45 216.00Kg 4.32
05. RCC 1:2:4(M 15)  144/2*0.45 324.00Kg 6.48
06. RCC 1:1.5:3(M 20) 1440/1.5*0.45  32.00Kg 8.64
07. RCC 1:1:2(M 25) 370.00Kg  7.40
08. RCC M 30 410.00Kg 8.20
09. RCC M35 445.00Kg 8.90
10. RCC M40  480.00Kg 9.60
11. Damp Proof Course CM 1:3,20mm tk 1440/3*0.022 10.56Kg  0.21
12. 2"tk precast slab M15 324*0.05 16.20Kg 0.32
13. 3"tk precast slab  M15 324*0.075 24.30Kg 0.49
14. GC Masonry CM 1:7 1440/7*0.34  70.00Kg1.40
15. Brick Work CM 1:6 1440/6*0.25 60.00Kg 1.20
16. Brick  Work CM 1:4, 115tk 1440/4*0.25*0.115 10.35Kg 0.21
17. Grano Flooring CC  1:1.5:3 1440/1.5*0.45*0.05 21.60Kg 0.43
18. Plastering CM 1:3, 12mm tk  1440/3*0.014 6.72Kg 0.13
19. Wall Plastering CM 1:4, 12mm tk  1440/4*0.014 5.00Kg 0.10
20. Laying Pressed Tiles Over a CM 1:4, 20mm tk  1440/4*0.022 7.92Kg 0.16

01. Any Concrete Work
(PCC, RCC) 0.45*35.315= 20.00
02. Damp  Proof Course
CM `1:3, 20mm tk 1.00
03. 2"tk Precast slab M15 1.00
04.  3"tk Precast slab M15 1.50
05. SS Masonry in CM 1:7 15.00
06. Brick Work  in CM 1:6 15.00
07. Brick Work in CM 1:4,115mm tk 2.00
08. Grano Flooring  in CC 1:1.5:3 1.00
09. Plastering in CM 1:3, 12mm tk 1.00
10. Wall  Plastering CM 1:4, 12mm tk 1.00
11. Laying Pressed Tiles over a CM 1:4, 20mm  tk 1.00
12. Ceramic Tiles, Marble, Granite, Cuddapah slab CM 1:4, 20mm  tk 1.00

UNIT WEIGHT:

01. Concrete 25 kN/m3
02. Brick 19 kN/m3
03.  Steel 7850 Kg/m3
04. Water 1000 Lt/m3
05. Cement 1440 Kg/m3
06. 1Gallon  4.81 Litres
07. Link 8" = 200mm
08. 1 Hectare 2.471 acr(10000m2)
09. 1  Acr 4046.82m2 = 100 cent

DEVELOPMENT LENGTH:


01. Compression 38d
02. Tension 47 &  60d
03. 1 Cent 435.60 Sft
04. 1 Meter 3.2808 ft
05. 1 M2 10.76  ft2
06. 1 Feet 0.3048m
07. 1 KN 100Kg
08. 1kN 1000N
09. 1 Ton 1000Kg  = 10,000 N = 10 kN
10. 1 kG 9.81N

BRICK:


Weight = 3.17 - 3.80 Kg
Water absorption 12 to  15%
Compressive strength = 36Kn/cm2
230mm Wall/m3 = 460 Bricks + 20Cft  Sand +
66Kg Cement

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