what is the procedure for quantity calculation for
- Thread starter TAMILSELVAN
- Start date
Dnyan Deshmukh
Staff member
For cement, sand and aggregates - estimate it from Mix design sheet quantity and the concrete quantity required
example say you need to cast a slab
quantity of slab = 100 cum (you need to calculate it by referring architectural and structural drawings)
Grade of concrete is specified as M25
Get the approved concrete mix design for M25 from your company, if not available you can get it done from third party testing laboratories, if you dont know how to do it.
Mix design sheet states all ingredients quantity put into 1 cum of concrete
say it states;
Cement - 300 Kg
Water - 150 Kg
Sand - 950 Kg
20mm aggregates - 800 kg
10mm Aggregates - 400 Kg
Now by referring mix design sheet, you can calculate required quantity of material by multiplying it with total volume of concrete required.
I will just show you how you calculate cement
300 Kg/cum x 100 cum = 30000 Kg = 30 MT
Like this you can calculate all materials.
For steel calculation
First you need to have Architectural and Structural drawing with you, verify all components are of same size in both drawing, if not raise a clarification sort to Architect and Structural Consultant.
If drawings are OK then
Start making BBS (Bar bending schedule) for each element like footings, columns, slabs and beams.
Then at the end of each BBS sheet make total of steel weights dia wise.
This will give required steel Quantity for each item you are going to execute in x amount of days.
According to quantities you got, do purchase material.
Dont forget to add the wastage of material which can happen at site during handling (it varies depending on drawings and control conditions at your project)
example say you need to cast a slab
quantity of slab = 100 cum (you need to calculate it by referring architectural and structural drawings)
Grade of concrete is specified as M25
Get the approved concrete mix design for M25 from your company, if not available you can get it done from third party testing laboratories, if you dont know how to do it.
Mix design sheet states all ingredients quantity put into 1 cum of concrete
say it states;
Cement - 300 Kg
Water - 150 Kg
Sand - 950 Kg
20mm aggregates - 800 kg
10mm Aggregates - 400 Kg
Now by referring mix design sheet, you can calculate required quantity of material by multiplying it with total volume of concrete required.
I will just show you how you calculate cement
300 Kg/cum x 100 cum = 30000 Kg = 30 MT
Like this you can calculate all materials.
For steel calculation
First you need to have Architectural and Structural drawing with you, verify all components are of same size in both drawing, if not raise a clarification sort to Architect and Structural Consultant.
If drawings are OK then
Start making BBS (Bar bending schedule) for each element like footings, columns, slabs and beams.
Then at the end of each BBS sheet make total of steel weights dia wise.
This will give required steel Quantity for each item you are going to execute in x amount of days.
According to quantities you got, do purchase material.
Dont forget to add the wastage of material which can happen at site during handling (it varies depending on drawings and control conditions at your project)
"Now by referring mix design sheet, you can calculate required quantity of material by multiplying it with total volume of concrete required.
I will just show you how you calculate cement
300 Kg/cum x 100 cum = 30000 Kg = 30 MT
Like this you can calculate all materials."
More over, after calculating the bulk materials in tons, if the transporter/store needs the information by volume like cu-ft/cu-m, then finding the bulk density and convert to volume.
For Example,
1. Sand for 1 cum. 950 Kg. For 100 Cum 95000 Kg or 95 Tons.
Weight of sand in 30 lit bulk density cylinder is coming around 48 Kg means, 48/30= 1.6 kg per litre.
For 1 Cum, 1600 kg per cum.
For 1 Cum 35.315 Cft, that means 1 Cft = 45.3 Kg.
So 95000/45.3= 2097 Cft sand required.
2. Directly 1 Cft = 28.317 lit.
So, 1.6 x 28.317 = 45.30 Kg per cft.
3. If bulk density cylinder is not available, simply we can use Mason's farma which is 1.25 cft.(12' x 12' x 15")
If the weight comes, 56.6 kg in that farma, 56.6/1.25=45.30 kg / cft.
WE NEED TO CONSIDER MOISTURE CONTENT IN SAND WHILE REACHING AT SITE.
MAXIMUM 10 TO 15% OF MOISTURE IS COMING ALONG WITH TRANSPORT.
(SIMPLY BULKAGE)
SO WE NEED TO ADD THAT 10 TO 15% ALSO WHILE ARRANGING THE SAND FOR CONCRETE WORK.
I will just show you how you calculate cement
300 Kg/cum x 100 cum = 30000 Kg = 30 MT
Like this you can calculate all materials."
More over, after calculating the bulk materials in tons, if the transporter/store needs the information by volume like cu-ft/cu-m, then finding the bulk density and convert to volume.
For Example,
1. Sand for 1 cum. 950 Kg. For 100 Cum 95000 Kg or 95 Tons.
Weight of sand in 30 lit bulk density cylinder is coming around 48 Kg means, 48/30= 1.6 kg per litre.
For 1 Cum, 1600 kg per cum.
For 1 Cum 35.315 Cft, that means 1 Cft = 45.3 Kg.
So 95000/45.3= 2097 Cft sand required.
2. Directly 1 Cft = 28.317 lit.
So, 1.6 x 28.317 = 45.30 Kg per cft.
3. If bulk density cylinder is not available, simply we can use Mason's farma which is 1.25 cft.(12' x 12' x 15")
If the weight comes, 56.6 kg in that farma, 56.6/1.25=45.30 kg / cft.
WE NEED TO CONSIDER MOISTURE CONTENT IN SAND WHILE REACHING AT SITE.
MAXIMUM 10 TO 15% OF MOISTURE IS COMING ALONG WITH TRANSPORT.
(SIMPLY BULKAGE)
SO WE NEED TO ADD THAT 10 TO 15% ALSO WHILE ARRANGING THE SAND FOR CONCRETE WORK.
Thank you !!
From your experience and point of view can you please provide the percentage of wastage to be added on estimation for cement, sand, aggregate, steel, tiles etc of construction materials.
