Most Important Points For Civil Site Engineers

Clear Cover to Main Reinforcement:

Footings: 50 mm

Raft foundation Top: 50 mm

Raft foundation Bottom / sides: 75 mm

Strap Beam: 50 mm

Grade Slab: 20 mm

Column: 40 mm (d>12 mm) 25 mm (d= 12 mm)

Shear Wall: 25 mm

Beams: 25 mm

Slabs: 15 mm or not less than diameter of the bar.

Flat Slab: 20 mm

Staircase: 15 mm

Retaining Wall on Earth: 20 / 25 mm

Water retaining structures: 20 / 30 mm

Sunshade: 25 mm


Weight of Rod per Meter Length. Diameter Weight per Meter (D^2/162)

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


Concrete Grade:

M5 = 1:5:10
M7.5=1:4:8
M10= 1:3:6
M15= 1:2:4
M20= 1:1.5:3
M25= 1:1:2
M30 and above grade based on design mix

What is D2/162.27 in steel ?

weight of steel bar per meter = Volume of steel x Density of steel

Weight of steel bar per meter = πD2/4 x 1000 mm (for 1m lenght) x 7850 kg/ 1000 mm x 1000 mm x 1000 mm

Weight of steel bar per meter = 3.14D2/4 x 7850/1000 x 1000 = 0.785D2 x 0.00785

Weight of steel bar per meter = 0.0061622 x D2 = D2/1/0.0061622 = D2/162.27

1 Cubic Meter Concretes 500 Bricks?

The Standard size of the 1st class brick is 190mm x 90mm x 90mm

and motor joint should be 10mm thick
So brick with motor=200 x 100 x 100.
Volume of 1st class brick = 0.19 x 0.09 X 0.09 = 0.001539 cu.m
Volume of 1st class brick with motor =0.2 x 0.1 x 0.1=0.002 cu.m
No. on bricks per 1cu.m= 1/volume of1st class brick with mortor ⇒ 1/0.002 ⇒ 500 No. of bricks

Calculate Quantities of Materials for Concrete -Cement, Sand, Aggregates for Grade M20:Ratio is 1:1.5:3

As we know that  during concreting when we place wet concrete , it gets harden after certain standard time( 30 mins IST & 10hrs FST)
volume of dry Concrete = 1.54 to 1.57 times Volume of wet concrete.
ratio Sum = 1+1.5+3=5.5
for using mix=1.57 m3 then cement required=1/ 5.5*1.57
=0.285m3*1440=411 kg. (8+bag)
sand requried=1.5/5.5*1.57=0.471m3
aggregate required=3/5.5*1.57=0.853m3

Unit Weight of Materials Used at Construction Site:

1- Water= 1000 Kg/ m3
2- Bricks (broken)= 1420 Kg/ m3
3- Bricks(common)= 1600 Kg/ m3
4- Cement(ordinary)= 1440 Kg/ m3
5- Cement (rapid hardening)= 1250 Kg/ m3
6-Cement Mortar= 2000 Kg/ m3
7- Cement Concrete (Plain)= 2400 Kg/ m3
8- Cement Concrete (Reinforced)= 2500 Kg/ m3
9- Glass= 2500 Kg/ m3
10- Lime Concrete= 1900 Kg/ m3
11- Cement Plaster= 2000 Kg/ m3
12- Lime Plaster= 1700 Kg/ m3
13 Stones (Ballast)= 1720 Kg/ m3
14- Stones (Aggregates)= 1750 Kg/ m3
15- Stones (Basalt)= 2850 Kg/ m3
16- Stones (Granite)= 2450 Kg/ m3
17- Stones (Marble)= 2650 Kg/ m3

18- Timber (Oak, Sal)= 510 Kg/ m3
19- Timber (Mango)= 650 Kg/ m3
20- Timber (Teak)= 625 Kg/ m3
21- Coal 600= Kg/ m3
22- Plastics= 1250 Kg/ m3
23- Oils= 800 Kg/ m3
24- Ashes= 650 Kg/ m3
25- Clinker= 750 Kg/ m3
26- Rubber= 1300 Kg/ m3
27- Slag= 1500 Kg/ m3
28- Clay Soil= 1900 Kg/ m3
29- Sand (dry)= 1540 to 1600 Kg/ m3
30- Sand (wet)= 11760 to 2000 Kg/ m3
31- Steel= 7850 Kg/ m3
32- Chalk= 2100 Kg/ m3
33- Bitumen= 1040 Kg/ m3

De-Shuttering time of different RCC Members:

For columns, walls, vertical form works: 16-24 hrs

Soffit formwork to slabs: 3 days (props to be refixed after removal)

Soffit to beams props: 7 days (props to refixed after removal)

Beams spanning upto 4.5m: 7 days

Beams spanning over 4.5m: 14 days

Arches spanning up to 6m: 14 days

Arches spanning over 6m: 21 days

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
M 30 ( 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)

M 35 ( 1 : 1.79 : 2.57)
Cement : 410 Kg/ M 3
20 mm Jelly : 632 Kg/ M 3
12.5 mm Jelly : 421 Kg/ M 3
River sand : 735 Kg/ M 3
Total water : 200 Kg/ M 3
Admixture : 0.7%
Fresh concrete density: 2400 Kg/ M 3
Note: sand = 735 + 2%, Water = 200- 14.7 =
185.30,
Admixture = 0.7%
M40 ( 1 : 1.67 : 2.39)
Cement : 430 Kg/ M 3
20 mm Jelly : 618 Kg/ M 3
12.5 mm Jelly : 412 Kg/ M 3
River sand : 718 Kg/ M 3
Water Cement ratio : 0.43
Admixture : 0.7%
Note: Sand = 718 + Bulk age 1%

M45 ( 1 : 1.58 : 2.26)
Cement : 450 Kg/ M 3
20 mm Jelly : 626 Kg/ M 3
12.5 mm Jelly : 417 Kg/ M 3
River sand : 727 Kg/ M 3 + Bulk age 1%
Water Cement ratio : 0.43
Admixture : 0.7%

M50 ( 1 : 1.44 : 2.23)
Cement : 450 Kg/ M 3
20 mm Jelly : 590 Kg/ M 3
12.5 mm Jelly : 483 Kg/ M 3
River sand : 689 Kg/ M 3 + Bulk age 12%
Water Cement ratio : 0.36 (188 Kg)
Admixture : 1.20%3
Micro silica : 30 Kg
Super flow 6.7% of cement

Standard Conversion Factors:

Length

1 kilometer (km) = 1000 meters (m)

1 meter (m) = 100 centimeter (cm)

1 centimeter (cm) = 10-2m

1 millimeter (mm) = 10-3m

1 micron (μ) = 10-6m

1 millimicron (mμ) = 10-9m

1 angstrom (A) = 10-10m

1 inch (in.) = 2.54 cm

1 foot (ft) = 30.48 cm

1 mile (mi) = 1.609 km

1 mil = 10-3 in.

1 centimeter = 0.3937 in.

1 meter = 39.37 in.

1 kilometer = 0.6214 mile

Area

1 square meter (m2) = 10.76 ft2

1 square mile (mi2) = 640 acres

1 square foot (ft2) = 929 cm2

1 acre = 43,560 ft2

Volume

1 liter (l) = 1000cm3 = 1.057 quart (qt) = 61.02 in3 = 0.03532 ft3

1 cubic meter (m3) = 1000 l = 35.32 ft3

1 cubic foot (ft3) = 7.481 U.S.gal = 0.02832 m3 = 28.32 l

1 U.S. gallon (gal) = 231 in3 = 3.785 l

1 British gallon = 1.201 U.S.gallon = 277.4 in3

Mass

1 kilogram (kg) = 2.2046 pounds (lb) = 0.06852 slug;

1 lb = 453.6 gm = 0.03108 slug

1 slug = 32.174 lb = 14.59 kg

Curing Days Required:

Super Sulphate cement : 7 days
Ordinary Portland cement OPC : 10 days
Minerals and Admixture added cement : 14 days