Calculation of Concrete Quantity for Staircase
We will discuss about the calculation of concrete quantity for staircase and also find out the volume of waist slab along with the number of risers and the number of tread in staircase. We will also try to look into what are incline length, horizontal length, flight height and landing in staircase.
What are the different parts of a Staircase?
The different parts of a staircase include riser, tread, landing, horizontal length, step, flight and inclined length.
Staircase: A staircase is essential in a building if one has to go from a lower floor to a higher floor. The staircase consists of components such as the riser, tread, flight, landing, etc.
Tread: The tread is the horizontal portion of a staircase. It is the area where one places their foot to climb the next step.
Riser: Vertical part of a stair.
Step: Step is the series of vertical risers and horizontal tread.
Flight: A series of steps excluding the platform makes a flight. A building staircase generally consists of two flights and a landing.
Waist slab: Inclined length of staircase.
Calculation of Concrete Quantity of a Staircase
First we have to calculate the volume of all steps
Height of building: 10 ft
If each flight have equal height
Height of landing: 10/2’=5’
Height of one flight: 5’
Riser: 6’’=6’’/12= 0.5 ft
Tread: 10’’=10’’/12= 0.833’
No of riser= height of flight/ 1 riser height
Number of riser: 5’/0.5=10
Number of tread= (riser-1)=10-1=9
Since number of tread is equal to the number of steps
No of steps= 9
One step length= 4 ft
Volume of all steps in a flight= ½*riser*tread*length of step* no of steps
Volume of step in one flight is therefore 7.497cft
Calculate Volume of Waist Slab in Staircase
To find the volume of waist slab in staircase we must find the horizontal length of the waist slab and also the inclined length of it.
Horizontal length= tread* no of steps
Horizontal length= 0.833*9=7.497’
Therefore, inclined length of waist slab= √(5*2+7.497*2)
= 9.012 feet
Volume of waist slab= incline length of each slab* length of step* thickness of waist slab
Thickness of slab= 6’’= 6’’/12= 0.5’
Volume= 9.012’* 4’* 0.5’= 18.024 ft
Volume of waist slab= 18.024ft
Calculate Volume of One Flight in Staircase
Volume of one flight is equal to sum of volume of all steps in one flight and volume of waist slab
Volume of one flight= volume of step+ volume of waist slab
= 7.497+ 18.024
Therefore, Volume of two flights= 25.521*2 = 51.042 cft
Calculation of Volume of Landing
Length= 8.5 ft
Thickness= 6’= 0.5’
Breadth= 4 feet
Volume of landing- L*B*T
Volume of landing= 8.5’*4’*0.5’= 17cft
Calculation of Total Volume of Staircase
Total volume= volume of two flights + volume of one landing
Total volume= 51.042+ 17= 68. 042 cft
Therefore, total concrete volume of staircase is 68.042 cft.
Calculation of Wet Volume and Dry Volume of Concrete
Wet volume= 68.042 cft
Dry volume is increased by 54% in concrete reinforcement. Therefore, a cofactor of 1.54 is added in wet volume to calculate dry volume
Dry volume= 68.042*1.54=104.78 cft
The mix ratio of concrete reinforcement is 1:1.5:3 in which one part is cement, 1.5 part is sand and 3 part is aggregate
Total ratio= 1+1.5+3= 5.5
Cement Required for Construction of Stairways
In mix ratio cement is 1 part of 5.5
Volume of cement= 1/5.5* dry volume
Volume of cement= 1/5.5* 104.78 cft
Volume of cement= 19.05 cft
Volume of 1 bag cement = 1.226cft
No of bags of cement= 19.05/ 1.226
No of bags of cement= 15. 538 bags
Calculation of Sand Quantity for Staircase
Mix ratio quantity of sand is 1.5 and total ratio is 5.5
Volume of sand= 1.5/5.5* 104.78
Volume of sand= 28.57 cft
Calculation of Aggregate Quantity of Staircase
Mix ratio quantity of aggregate was 3 and total ratio is 5.5
Volume of aggregate= 3/5.5*104.78
Volume of aggregate= 57.15 cft
Quantity of Steel Required for Staircase Construction
0.5% to 0.1 percent of steel reinforcement used in slabs from which we have taken about 0.75 % of steel reinforcement of dry volume of concrete
Density of steel= 7850 kg/m3
Weight of steel= volume* density
Steel quantity= (0.75*140.78*7850)/ (100*35.315)
Weight of steel= 174.68 kg