Thumb Rules used in Construction For Civil Engineers | Read Here
Thumb rule to calculate the Steel quantity required for Slab, Beams, Footings & Columns:
For Residential buildings :- 4.5Kgs-4.75Kgs /SFT
For Commercial buildings :- 5.0Kgs-5.50Kgs/SFT
As per B N Datta, the Steel quantity used in different members of the building can be calculated easily using the following recommendations.
|Structural Member||Percentage of Steel|
|Slab||1% of total volume of concrete|
|Beam||2% of of total volume of concrete|
|Column||2.5% of total volume of concrete|
|Footings||0.8% of total volume of concrete|
How to calculate the steel quantity of slab having the Length, width, and depth of the slab is 5m x 2m x 0.15m
Step 1: Calculate the Volume of Concrete
Total Volume of Concrete for above given Slab is 5 x 2x 0.15 = 1.5 m3
Step 2: Calculate the steel quantity using formula
As per the above table, the steel quantity of slab is 1% of the total volume of concrete utilized.
Thumb rule to calculate Steel quantity of above slab = Volume of Concrete x Density of Steel x % of Steel of Member
Steel quantity required for above slab = 1.5 x 7850 x 0.01 = 117.7 Kgs
Thumb rule for Cement, Sand, Coarse Aggregate Quantity in Different grades of Concrete :
|Concrete Mix||Cement Quantity||Coarse Aggregate Quantity||Fine Aggregate Quantity|
|M5 (1:5:10)||2.82 Bags||0.98m3||0.49m3|
Note: 1 bag of cement = 50Kgs
Thumb rule to calculate the Concrete Volume with respect to area:
The Concrete Volume of 0.038m3 of concrete is used for each Square Feet of Plan area
From below fig: Plan Area = 20 x 20 = 400SFT
The plan area is 400SFT then the total volume of concrete required = 400 x 0.038m3 = 15.2 m3
Thumb rule for Cement quantity in Brickwork, Cement Masonry & Plastering work in construction:
Brickwork Thumb rule:
|Brickwork for 1m3||Cement Qty|
|230 mm Brickwork||0.876bags/m3||43.80kgs|
|115 mm Brickwork||0.218bags/m3||10.90kgs|
Cement Masonry Quantity Thumb Rule:
|Cement Masonry Type & Mix||Cement Qty in Bags||Cement Qty in Kgs|
|200mm in Cement Masonry work of ratio 1:6||0.124Bags/m2||6.2Kgs/m2|
|150mm in Cement Masonry work of ratio 1:6||0.093Bags/m2||4.65Kgs/m2|
|200mm in Cement Masonry work of ratio 1:4||0.206Bags/m2||10.3Kgs/m2|
|150mm in Cement Masonry work of ratio 1:4||0.144Bags/m2||7.2Kgs/m2|
|100mm in Cement Masonry work of ratio 1:4||0.103Bags/m2||5.15Kgs/m2|
Plastering Quantity Thumb Rule:
|Type of Plastering||Cement Qty in Bags||Cement Qty in Kgs|
|Internal Wall Plastering||0.09Bags/m2||4.5Kgs/m2|
|External Wall plastering||0.175Bags/m2||8.75Kgs/m2|
Thumb rule to calculate the Shuttering area:
Shuttering costs 15-18% of the total construction of the building. Shuttering is framed to bring the concrete in Shape. Thumb rule to calculate the shuttering required is 6 times the quantity of concrete or 2.4 times of Plinth area.
Suppose, the concrete quantity is 1.5 m3 then the shuttering area required is 1.5 x 6 = 9m2
Components of Shuttering:-
Shuttering Ply, Battens, Nails are components of Shuttering.
Shuttering Ply Quantity calculation:
The shuttering Ply has a length, width & depth of 2.44 x 1.22 x 0.012
The No. of Shuttering Ply sheets = 0.22 times of Shuttering
Suppose, the area of shuttering required = 2m2
Then the Shuttering Ply required = 0.22 x 2 = 0.44 m2
Battens Quantity Calculation:
Shuttering batten usually have a length & width of 75mm x 40mm.
Batten Quantity = 19.82 x No. of Ply Sheets
if the construction requires 25 Ply sheets, the total quantity of Battens are 19.82 x 25 = 495 Battens
Nails & Binding Wire Quantity in Shuttering:
75gms of Nails are used for 1m2 of Shuttering
75gms of Binding wire is consumed for every 1m2 of Shuttering.
Thumb rule for Shuttering oil Quantity:
Shuttering oil is used to de-frame or de-assemble from the concrete easily.
Total required Shuttering oil is = 0.065 x Total Area of Shuttering
For every 15m2 of shuttering 1 litre of shuttering oil is consumed.
10m2 is total area of shuttering, then Shuttering oil required = 0.065 x 10 = 0.65 lts