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Stair Case

The document provides design details for a dog-legged stair case and an open newel stair case. For the dog-legged stair case, it specifies the geometry, loads, calculates the required slab thickness and reinforcement. The main reinforcement is specified as 12mm bars at 150mm c/c. For the open newel stair case, it again specifies the geometry, calculates loads, slab thickness, required reinforcement for three spans AB, BC, CD. The main reinforcement is specified as 16mm bars at 100mm c/c.

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Anand3101
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211 views5 pages

Stair Case

The document provides design details for a dog-legged stair case and an open newel stair case. For the dog-legged stair case, it specifies the geometry, loads, calculates the required slab thickness and reinforcement. The main reinforcement is specified as 12mm bars at 150mm c/c. For the open newel stair case, it again specifies the geometry, calculates loads, slab thickness, required reinforcement for three spans AB, BC, CD. The main reinforcement is specified as 16mm bars at 100mm c/c.

Uploaded by

Anand3101
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as XLS, PDF, TXT or read online on Scribd
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Design of Dog-legged stair case

Given Data
Height between floor= 3.6 m
Riser=R 150 mm
Tread=T 250 mm
Width of flight 2.75 m
Length of landing 1.23 m
Length of staircase 2.75 m
Live load= 5 kN/m2
Finishes load= 1 kN/m2
For calculation take b of slab = 1000 mm
Fck= 20 N/mm2
Fy = 415 N/mm2
Effective span=c/c between supports 4.787 m
4787 mm
Clear cover= 20 mm
Diameter of bar= 12 mm

1) Depth of slab
Thickness of waist slab= L/20 170.96429 mm
Therefore thickness is 175 mm
0.175 m
Assuming 20 mm clear cover and 12 mm diameter of bar
Effective depth= d 149 mm

The slab thckness in the landing regions may be taken as 200 mm as the
bending moments are relatively low here. 175 mm

2) Loads
Self weight of waist slab 4.724 kN/m2
Self weight of steps 1.875 kN/m2
Finishes 1 kN/m2
live load 5 kN/m2
Total 12.599 kN/m2

Factored load 18.899 kN/m2

Loads on landing
Self weight of slab 4.375 kN/m2
Finishes 1 kN/m2
live load 5 kN/m2
Total 10.375 kN/m2

Factored load 15.563 kN/m2

3) Design moment
R 35.557 kN/m
Maximum moment at midspan
38.269 kNm/m

4) Main reinforcement
R 1.724 N/mm2
Ast required 801.098 mm2/m

Assume diameter of bar φ 12 mm

Spacing of bars 141.178 mm


provide = 150 mm
Provide12mm diameter of bar @ 150c/c

5) Distributors
Ast required 210 mm2/m

Assume diameter of bar φ 8 mm

Spacing of bars 239.359 mm


provide = 250 mm
Provide8mm diameter of bar @ 250c/c
Design of open newel stair case
Given Data
Riser=R 150 mm
Tread=T 300 mm
Width of flight 1.5 m
Length of tread = 1.5 m
Live load= 4 kN/m2
Finishes load= 150 N/m
For calculation take b of slab = 1000 mm
Fck = 20 N/mm2
Fy = 415 N/mm2
Ru max = 2.76
Effective span AB = 4.5 m
Effective span BC = 4.735 m
Effective span CD = 4.5 m
Clear cover= 20 mm
Diameter of bar= 16 mm
Concrete density = 25

FOR SPAN AB
1) Depth of slab
Thickness of waist slab=L/(20*M.F) = 142.41 mm
Therefore provide thickness = 200 mm
Assuming 20 mm clear cover and 12 mm diameter of bar
Effective depth= d 172 mm

2) Loads
a. Load on 1st flight
Self weight of waist slab 8385 N/m
Self weight of each steps 2812.5 N/m
Finishes 150 N/m
live load 6000 N/m
Total = 17348 N/m
Factored load = 26022 N/m

b. Total Load on landing = 14535 N/m


Factored load = 21803 N/m

3) Design moment
Maximum load = 26022 N/m
Maximum moment at midspan
Mu max = 65867 N-mm

4) Main reinforcement
Ast required 1250 mm2
Assume diameter of bar = φ = 16 mm
Spacing of bars 160.908 mm
provide spacing = 100
Provide 16 mm diameter bar @ 100 mm c/c

5) Distributors
Ast required 300 mm2
Assume diameter of bar = φ = 8 mm
Spacing of bars 167.552 mm
provide spacing = 150
Provide 8 mm diameter bar @ 150 mm c/c

6) Check for depth


d= 155 mm < 200
Therefore safe

FOR SPAN BC
1) Depth of slab
Thickness of waist slab=L/(20*M.F) = 149.84 mm
Therefore provide thickness = 200 mm
Assuming 20 mm clear cover and 12 mm diameter of bar
Effective depth= d 172 mm

2) Loads
a. Load on 1st flight
Self weight of waist slab 8385 N/m
Self weight of each steps 2812.5 N/m
Finishes 150 N/m
live load 6000 N/m
Total = 17348 N/m
Factored load = 26022 N/m

b. Total Load on landing = 14535 N/m


Factored load = 21803 N/m

3) Design moment
Maximum load = 26022 N/m
Maximum moment at midspan
Mu max = 72926 N-mm

4) Main reinforcement
Ast required 1417 mm2
Assume diameter of bar = φ = 16 mm
Spacing of bars 141.871 mm
provide spacing = 100
Provide 16 mm diameter bar @ 100 mm c/c

5) Distributors
Ast required 300 mm2
Assume diameter of bar = φ = 8 mm
Spacing of bars 167.552 mm
provide spacing = 150
Provide mm mm diameter bar @ 150 mm c/c

6) Check for depth


d= 163 mm < 200
Therefore safe

FOR SPAN CD
1) Depth of slab
Thickness of waist slab=L/(20*M.F) = 142.41 mm
Therefore provide thickness = 200 mm
Assuming 20 mm clear cover and 12 mm diameter of bar
Effective depth= d 172 mm
2) Loads
a. Load on 1st flight
Self weight of waist slab 8385 N/m
Self weight of each steps 2812.5 N/m
Finishes 150 N/m
live load 6000 N/m
Total = 17348 N/m
Factored load = 26022 N/m

b. Total Load on landing = 14535 N/m


Factored load = 21803 N/m

3) Design moment
Maximum load = 26022 N/m
Maximum moment at midspan
Mu max = 65867 N-mm

4) Main reinforcement
Ast required 1250 mm2
Assume diameter of bar = φ = 16 mm
Spacing of bars 160.908 mm
provide spacing = 100
Provide 16 mm diameter bar @ 100 mm c/c

5) Distributors
Ast required 300 mm2
Assume diameter of bar = φ = 8 mm
Spacing of bars 167.552 mm
provide spacing = 150
Provide mm mm diameter bar @ 150 mm c/c

6) Check for depth


d= #REF! mm < 200
Therefore #REF!

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