Design of R.C.C. Stair
There are two types of R.C.C. stairs:
● Stair spanning horizontally
● Stairs spanning longitudinally
Stair spanning horizontally:
A stair which is supported by walls or
beams on both sides OR beam on one side and wall on other side is
called stair spanning horizontally.
Q1: A flight of stairs to be provided in an office building is to be
supported by a stringer beam on one side and a brick wall on the
other side. The width of the stairs is 1/50 meter. The risers are 15 cm
and treads are 27 cm. Design the stair allowing a live load of 300
kg/m2. fc’ = 15 MPa, fy = 280 MPa
Given Data:
Effective span = l = 1.5 m
Riser = R = 15 cm
Tread = T = 27 cm
Live Load = w1 = 300 kg/m2
fc’ = 15 MPa
fy = 300 kg/m2
Solution:
Let thickness of waist = 75 mm = 7.5 cm (minimum value)
Breadth of steps = b = √T2 + R2 = √272 + 152 = 30.89 cm
Overall depth = D = T*R/b = + thickness of waist
= (27 * 15/30.89) + 7.5 = 20.61 cm
LOAD PER METER RUN
Dead load of triangular step = ½ * 0.27 * 0.15 * 2300 = 46.58 kg/m
Dead load of waist per unit length = 0.3089 * 0.075 * 2400 = 55.6
kg/m
Total dead load = 46.58 + 55.60 = 102.18 kg/m
Live load per meter run = 0.27 * 300 = 81 kg/m
There are two types of R.C.C. stairs:
● Stair spanning horizontally
● Stairs spanning longitudinally
Stair spanning horizontally:
A stair which is supported by walls or
beams on both sides OR beam on one side and wall on other side is
called stair spanning horizontally.
Q1: A flight of stairs to be provided in an office building is to be
supported by a stringer beam on one side and a brick wall on the
other side. The width of the stairs is 1/50 meter. The risers are 15 cm
and treads are 27 cm. Design the stair allowing a live load of 300
kg/m2. fc’ = 15 MPa, fy = 280 MPa
Given Data:
Effective span = l = 1.5 m
Riser = R = 15 cm
Tread = T = 27 cm
Live Load = w1 = 300 kg/m2
fc’ = 15 MPa
fy = 300 kg/m2
Solution:
Let thickness of waist = 75 mm = 7.5 cm (minimum value)
Breadth of steps = b = √T2 + R2 = √272 + 152 = 30.89 cm
Overall depth = D = T*R/b = + thickness of waist
= (27 * 15/30.89) + 7.5 = 20.61 cm
LOAD PER METER RUN
Dead load of triangular step = ½ * 0.27 * 0.15 * 2300 = 46.58 kg/m
Dead load of waist per unit length = 0.3089 * 0.075 * 2400 = 55.6
kg/m
Total dead load = 46.58 + 55.60 = 102.18 kg/m
Live load per meter run = 0.27 * 300 = 81 kg/m
