Volume Calculation of Concrete Staircase
The maximum riser of the staircase should be 7 inches and a minimum of 4 inches. The minimum tread should be 10 inches and a maximum of 12 inches or 1 feet. The breadth of the stair should be 5 feet. The landing of the stair should be a minimum of 10 feet 6 inches. The spacing among two flights should be a minimum of 6 inches. The steps in the stair range from 1 to 9. The waist thickness of the slab should be a minimum of 6 inches.
The calculation is done on the basis of the following dimensions:-
Height of floor = 10 feet
Height of one flight = 10/2 = 5 feet
Height of Risers = 6 inches = 0.5 feet
Number of risers = Height of flight/Riser = 5/0.5 = 10 nos.
So, total steps along with landing = 10 nos.
Length of tread = 10 inches = 0.8 feet
Number of treads = (Number of risers – 1) = 10 – 1 = 9 nos.
Thickness of waist slab = 6 inches = 0.5 feet
Length of step = 5 feet
With the use of the following formula, the volume of concrete will be determined for steps:-
Volume of one step = 1/2 x riser x tread x length of step
After putting all the values, we get the following:-
1/2 x 0.5 x 0.83 x 5 = 1.03 cubic feet
As there are 9 number of steps in a flight, so the volume of steps for first flight = 9 x 1.03 = 9.27 cubic feet
Now, it is required to determine the concrete volume for the waist slab. Before that, you have to find out the inclined length of the waist slab by applying the following formula:-
√(horizontal length)2 + (height)2
But, the horizontal length & height is unknown here.
The horizontal length will be computed as follow:-
The horizontal length of waist slab = Tread x Number of Steps
After putting the values, we get the following:-
0.8333 X 9 = 7.4 feet
Now, it is required to determine the height of the top of the landing from floor as follow:-
Number of riser x Height of riser = 10 x 0.5 = 5 feet
So, inclined length of waist slab = √(horizontal length)2 + (height)2
= √(7.4)2 + (5)2 = √79.96 = 8.93 feet