Civil Engineering Basic Knowledge Thumb Rules for Civil Engineering
There is a number of thumb Rule For Civil Engineers that we used in construction work. So, the following are some most frequently used Thumb rules on the Construction site.
The Thumb rule method is an approximate & comparing method. In thumb rules and the units are not the same when we compare to get the results. So, ignore units while performing the thumb rule.
Thumb Rules for Construction:
following are thumb rule in civil engineering,
1) Thumb Rule for Concrete Volume:
The volume of concrete required = 0.038 m3/square feet area
Example:-If Plan Area = 40 x 20 = 800 Sq. m.
So, for the plan area of 800 Sq. m. the area the total volume of concrete required
= 800 x 0.038m3 = 30.4m3
2) Thumb Rule for Steel Quantity for Slab, Beams, Footings & Columns:
Following are some important thumb rule for steel calculation y for slab, beam, column and footings.
Steel required in residential buildings = 4.5 Kgs – 4.75 Kgs / Sq. Ft.
Steel required For Commercial buildings = 5.0 Kgs-5.50 Kgs/Sq. Ft.
The following recommendations Thumb Rules For Civil Engineering are given in B N Datta for the Steel quantity used in different members of the building
3) Percentage of Steel in Structural Members:
following are thumb rule for reinforcement in concrete members,
1) Slab – 1% of the total volume of concrete (Slab steel calculation thumb rule)
2) Beam – 2% of the total volume of concrete
3) Column – 2.5% of total volume of concrete
4) Footings – 0.8% of the total volume of concrete
Example:
How to calculate the steel quantity of slab having the Length, width, and depth of the slab is 5m x 4m x 0.15m
Step 1: Calculate the Volume of Concrete
The Total Volume of Concrete for given Slab = 5 x 4 x 0.15
= 3m3
thumb rule for steel in rcc
Step 2: Calculate the steel quantity using formula
As per the guidelines are given in the B N Dutta reference book the steel quantity of slab is 1% of the total volume of concrete utilized.
Thumb rule to estimate Steel quantity of above slab = Volume of Concrete x Density of Steel x % of Steel of Member
Steel weight required for above slab = 3 x 7850 x 0.01 = 235Kgs
4) Thumb Rules For Shuttering Work:
Shuttering costs is taken as 15-18% of the total construction of the building. Shuttering work is done to bring the concrete in Shape. Thumb rule to estimate the shuttering required is 6 times the quantity of concrete or 2.4 times of Plinth area.
For example, the concrete quantity is 0.5m3, then
Area of Shuttering is 0.5 x 6 = 3m2
Components of Shuttering:-
The Shuttering plate Ply, Battens, Nails are components of Shuttering.
Shuttering Ply Quantity estimation:
Suppose, 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 shuttering area = 3m
Then Ply required for shuttering = 0.22 x 3 = 0.66m2
5) Battens Quantity Calculation:
Shuttering batten usually has a length & width of 75mm x 40mm.
Batten Quantity = 19.82 x No. of Ply Sheets
If work requires 25 Ply sheets, the total quantity of Battens are 19.82 x 25 = 495 Battens
Nails & Binding Wire Quantity in Shuttering:
Approximately, 75 gams of Nails used in the shuttering of the 1m2 area.
75gms of Binding wire is used for every 1m2 of Shuttering.
Thumb rule for Shuttering oil estimation :
Shuttering oil is applied on the shuttering plate surface used to de-frame or de-assemble from the concrete easily.
Total required Shuttering oil = 0.065 x Total Area of Shuttering
(or)
For every 15m2 of shuttering 1 liter of shuttering oil is consumed.
Example :
If, total area of shuttering is 15 m2, then Shuttering oil Consumption = 0.065 x 15 = 0.975.
6) Thumb Rule for Cement, Sand, Coarse Aggregate Quantity Calculations:
Note: 1 bag of cement = 50Kgs
Thumb rule for Cement required in Brickwork, Cement Masonry & Plastering work in construction:
7) Thumb Rules For Civil Engineers for Brickwork:
following are Thumb Rules for civil engineering for brick work and cement quantity calculations.
| Brickwork for 1m3 | Cement Qty in m3 | Cement Qty in Bags |
| 230 mm Brickwork | 0.876m3 | 25.4 Bags |
| 115 mm Brickwork | 0.218m3 | 6.32 Bags |
8) Thumb Rules For Cement Masonry Quantity:
| 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 |
8) Thumb Rules Plastering Quantity :
| Type of Plastering | Cement Qty in Bags | Cement Qty in Kgs |
| Rough Plastering | 0.09 Bags/m2 | 4. 5Kgs/m2 |
| Internal Wall Plastering | 0.09 Bags/m2 | 4.5 Kgs/m2 |
| Duct Plastering | 0.09 Bags/m2 | 4.5 Kgs/m2 |
| External Wall plastering | 0.175 Bags/m2 | 8.75 Kgs/m2 |
| Stucco Plastering | 0.175 Bags/m2 | 8.75 Kgs/m2 |
| Lathen Plastering | 0.55 Bags/m2 | 27.5 Kgs/m2 |
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