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Name-Subhankar Chandra Kirtania
Class –B.C.E.[IV] ; Section-A1 ; Roll No-000610401009
1
Design Of Staircase
All Dimensions are in meter
Floor to Floor height of the building is 3.0 meter. And clear dimension for the stair-hall is
4.70mX3.50m. Now if we take Riser(R)=150 mm no of riser needed =
=20.We go for dog-legged
stair case with width of each flight taken as 1650mm. Now no of riser needed per flight
= 2.
/ 3 .Now taking tread width =300mm total space needed for tread
=(9X300)mm=2700mm.Now we Take mid-landing width 1650mm .
So effective length(le) =4950mm. Assuming overall depth(D)=
Providing overall depth of the waist slab,D = 130 mm.(Here waist slab of the stair is embedded
125mm inside 250mm brick wall)
Load calculation
On Landing portion-
Dead Load
i. s/w of waist slab = .13X25 = 3.25 KN/m2
ii. s/w of floor finish celling plaster etc.(assumed) = 1 KN/m2
_________________________________________________________________________
Total DL =4.25KN/m2
Name-Subhankar Chandra Kirtania
Class –B.C.E.[IV] ; Section-A1 ; Roll No-000610401009
2
Now for 1.65 m wide waist slab Dead Load intensity on landing portion=(1.65X4.25)
KN/m=7.0125KN/m
Live Load
As per IS:456-200,cl-33.2,pg-63 live load intensity on the landing portion may be taken as
*( ) + ⁄ = 7.5 KN/m
Total loading intensity on landing portion ( )=(7.0125+7.5)KN/m=14.5125KN/m
On Inclined portion-
Dead Load
i. For s/w of waist-slab, floor-finish, ceiling-plaster
.
/ (
√
) (
√
)
ii. s/w of step = 12R=12X0.15
_________________________________________________________________
Total DL
Now for 1.65 m wide waist slab Dead Load intensity on Inclined portion
( 1.65)KN/m=10.8108KN/m
Total loading intensity on inclined portion ( )=( )
Let us consider maxm intensity of loading acting over the whole span –
Ma=Mb=.
/
W2=18.3108 KN/m W1=14.5125 KN/m
Name-Subhankar Chandra Kirtania
Class –B.C.E.[IV] ; Section-A1 ; Roll No-000610401009
3
Ultimate mt. =Mu=
.
/
For M25 concrete & Fe-500 steel
= 0.46(from IS-456:2000,pg-70 for fy=500) and =25;
So Q=3.340152
√
( ) } As per IS:456-200,cl-33.2,pg-63 effective breadth could be
taken as (b+75)mm.
Assuming 10 bars & 20mm clear cover D=(98.66+5+20)=123.66mm 125mm Dassumed (Hence
OK)
Exact calculation
For case-
=29.632KN-m
For case-
, ( )-=6.3193KN-m
(a=1.825m,b=3.125m,s=2.7m,l=4.95m,w=3.7983KN)
, ( )-=4.218KN-m
Total--- MA=35.952 KN-m
MB=33.850 KN-m
MA>MB
Hence Ultimate moment(Mu)=1.5X35.952 KN-m=53.928 KN-m
W1=14.5125KN/m
CASE Ι
W=( W2 – W1)=3.7983 KN/m
CASE ΙΙ
(a) (b)
(s)
(l)
Name-Subhankar Chandra Kirtania
Class –B.C.E.[IV] ; Section-A1 ; Roll No-000610401009
4
4
5
Dreqd=(96.74+20+5)=121.75mm Dprovided=130 mm
dprovided=(130-25)mm=105mm dreqd
________________________________________________________________________________________________________________
RA = 42.82 KN RB = 40.13 KN
Span moment will be maxm where shear force will be zero-
The distance from ‘A’ 2 .
/3
Maxm Span moment,
0( ) 2 .
/3 2
( )
31
= 18.5389 KN-m
MA=35.952
KN-m
MB=33.850 KN-m
case-ΙΙΙ RAΙΙΙ .
𝐴 𝐵𝑙
/ 𝐾𝑁 RBΙΙΙ .
𝐴 𝐵𝑙
/ 𝐾𝑁
case-ΙΙ RAΙΙ .
𝑤 𝑠 𝑏
𝑙/ 𝐾𝑁 RB
ΙΙ .𝑤 𝑠 𝑎
𝑙/ 𝐾𝑁
case-Ι RAΙ .
W l
/ 𝐾𝑁 RB
Ι .W l
/ 𝐾𝑁
W2=18.3108 KN/m
W1=14.5125KN/m
Name-Subhankar Chandra Kirtania
Class –B.C.E.[IV] ; Section-A1 ; Roll No-000610401009
5
REINFORCEMENT DETAILS
(with the help of SP:16 1980:-table-3,page-49,for y=500 & page-230)
effective depth
For supports , dx=(D-20-4)mm=106 mm(for 8 distributer bars at bottom)
For span bottom, dy=(D-20)mm= 110 mm(for 12 main bars at bottom)
Here
=.
/
=257.4 mm2
Spacing reqd for 8 distributers =(
)
Spacing provd = 300 mm C/C
Condn
Moment
(KN-m)
Ultimate Moment
(KN-m)
4
( ) 5
Pt
=(%steel )
( )
(
)
Spacing(mm)
At support top ‘A’
35.952 53.93 2.7825 0.7544
1319.45 10@150mmC/C+
8@150mmC/C
(552.92+863.94)
=1416.86
At support top ‘B’
33.850 50.78 2.6246 0.7029
1238.12 10
@100mmC/C 1295.91
At mid span
bottom
18.5389 27.81 1.3324 0.328424
596.1 10
@200mmC/C 647.95