Design of slabs by strip method. Link for video and related awesome materials you tube : civil engineering 4 free

1. b= 4.5m
a= 6m
How to determine Design moment for
a slab using StripMethod

2. Determine the design moment for rectangular slab shown below using strip method
a= 6m b = 4.5m t = 150mm
Use C-25 concrete & S-300 steel , Take variable load ,
Floor finish, 30mm cement screed and 20 mm thick marble
b= 4.5m
a= 6m
2
Q=3kN/m

3. Step 1 Divide the slab in to rectangular strips
a= 6m
b= 4.5m
b/4
b/4
b- b/2
/ 2
w
/ 2
w
/ 2
w
/ 2
w
w w
w
b/4

4. Step 2 Determine the design load , Wd
+
Design load 1.3Gk 1.6Qk

Gk
Where = Permanent load
Qk =Variable load
Self weight of slab = . *h
R C


h
= Unit weight
= thickness
3
25 / * 0.15
kN m m

2
3.75 /
kN m

Self weight of Cement screed= *h
c

3
23 / * 0.03
kN m m

2
0.69 /
kN m

Self weight of Marble= *h
M

3
27 / * 0.02
kN m m

2
0.54 /
kN m


5. Total permanent load = Gk Slab + Gk Cement screed + Gk Marble
2
(3.75 0.69 0.54) /
kN m
  
2
4.98 /
kN m

+
Design load(Wd) 1.3Gk 1.6Qk

2 2
+
1.3*4.98 / 1.6*3 /
kN m kN m

2
11.27 /
kN m

2
Design load(Wd) 11.27 / * 1 =11.27 /
kN m m kN m


6. a= 6m
b= 4.5m
b/4
b/4
b- b/2
/ 2
w
/ 2
w
/ 2
w
/ 2
w
w w
w 1
1
Step 3 Determine the design moment in each strip
Strip 1-1
11.27 /
w kN m
 11.27 /
w kN m

2
*
4 8 32
= *
x
b b wb
w
m 
2
32
11.27*4.5
7.13 . /
x kN m m
m 

b/4

7. a= 6m
b= 4.5m
b/4
b/4
b- b/2
/ 2
w
/ 2
w
/ 2
w
/ 2
w
w w
w
2 2
Step 3 Determine the design moment in each strip
Strip 2-2
/ 2 5.64 /
w kN m

2
2 *
2 4 8 64
= *
x
b b wb
w
m 
2
2 64
11.27*4.5
3.56 . /
x
kN m m
m 

b/4
/ 2 5.64 /
w kN m


8. a= 6m
b= 4.5m
b/4
b/4
b- b/2
/ 2
w
/ 2
w
/ 2
w
/ 2
w
w w
w
3
3
Step 3 Determine the design moment in each strip
Strip 3-3
11.27 /
w kN m

3
2
8
=
y
wb
m
2
3 8
11.27*4.5
28.53 . /
y
kN m m
m 

4.5 m

9. a= 6m
b= 4.5m
b/4
b/4
b- b/2
/ 2
w / 2
w
/ 2
w / 2
w
w w
w
4
4
Step 3 Determine the design moment in each strip
Strip 4-4
/ 2 5.64 /
w kN m

2
4 *
2 4 8 64
= *
y
b b wb
w
m 
2
4 64
11.27*4.5
3.56 . /
y
kN m m
m 

b/4
/ 2 5.64 /
w kN m
