Flat Slab Design 4.35m x 4.35m

Design of Flat Slab

A) LOADINGS Concrete Density Sla t!ickness #anel Dro% %anel

= = = =

24.00 kN/m3 0.2" m $ 4.3" $ &."0

4 .3 " & ." 0

Dea' Loa' (t o sla (t o 'ro%  ,otal  ,otal

= = =

&&3.*4 kN +.&0 kN &2&.+4 kN

 ,otal  ,otal

= =

2".00 kN/m2 4*3.3 kN

=

"".*+ kN

Li-e Loa'

 ,otal  ,otal nactore' loa'

 ,!ereore ltimate loa' on t!e 1oor  = an' ei-alent 'istrite' loa' n =

2+.+* kN %er %anel

4.00 kN/m2

B) ANALYSIS

5ecti-e s%an L = 3 .3 " m Dro% %anel6s 'imension 7 &/3 %anel 'imension. ,!ereore colmn stri% = (i't! o 'ro% %anel = &."0 m a) Centre of interior span

#ositi-e moment

=

22&.20 kNm

8i't! o mi''le stri%

= 7

2.+" m &/2 %anel 'imension

 ,!ereore %ro%ortion o moment taken taken y mi''le stri% = 0."  ,!s t!e mi''le stri% %ositi-e moment = &30.4 kNm  ,!e colmn stri% %ositi-e moment = 0.*0 kNm '

=

220.00

 c

=

 y

=

i) Middle strip 9

=

<0.2" ? 9/0.)@0." ; As

ii) Column strip 9

= =

=

0.4: 0.4" 20.00

=

&":0.&4 mm2 <&4,&2  200mm)

=

0.04

<0.2" ? 9/0.)@0." ; As

0.03

= =

= =



=

0.4" 0.4" 20.00

&0+4.43 mm2 <&0,&2  &+*." mm)

b) Interior Support 

Ne>ati-e moment

= =

?0.0""L ?&*&.3" kNm

an' t!is is also 'i-i'e' to #ro%ortion taken y mi''le stri%

= = =

#ro%ortion taken y colmn stri% or t!e mi''le stri% 9 = <0.2" ? 9/0.)@0." ; As

0.04 = =

=

20.00

= :*&.42 mm2 <:,&2  "*0 mm)

or t!e colmn stri% ' = 9 = <0.2" ? 9/0.)@0." ; As

c) Punching Shear  1) At the column head:

0.4: 0.4"

= =

3:".00 0.03 = =

0.4* 0.4" 34:.*"

+30.0 mm2 <+,&2  200mm)

0.33 ?":.&: ?&&".&

'iameter o colmn !ea' %erimeter  = =

= *00.00 mm  $ 'iameter o colmn !ea' 2&.&& mm

S!ear orce B

=  ? /4<'iameter o colmn !ea')@2n = &0.02 kN  ,o allo( or t!e e5ects o moment transer B is increase' y &" t!s = &.&"B/' &.30 N/mm2 =  2) irst critical %erimeter is &."' t!s t!e len>t! o %erimeter  Fltimate s!ear orce t!s s!ear stress -

0.+ c

=

= = = = = =

"4*."0 mm 4
= As

=

&00As/'

=

-c

=

4.3+

&"+2.00 mm

0.2 0.*<&00As/')@&/3<400 0.43 N/mm

= -  -c t!ereore t!e section is a'eate in %nc!in> 3) At t!e 'ro%%e' %anel critical section is

= = =

an' %erimeter  Calclate' s!ear B

= =

2

2

Dro%%e' %a 2.&: +:40.00

 ? 2 $ n *00.2* kN

t!s t!e s!ear stress -

0.42 N/mm

= 

2

-c

t!s t!e section is a'eate. Span-Eective Depth Ratio

At t!e centre o s%an K/'2 Asre

=

0.4

=

&":0.&4 mm2

As%ro-

=

&"+2.00 mm2 2 2+3."3 N/mm

 s

=  ,!ereore mo'iHcation actor As sc! S%an L = e5ecti-e 'e%t! =

= 4.3" m 220.00 mm

&.42

limitin> s%an/e5ecti-e 'e%t! actal s%an/e5ecti-e 'e%t!

= =

3*.02 &.*

m $

0.&" m

<& no 2"0$2"0 C #ile)

30.00 N/mm2 4:0.00 N/mm2

&."0 m

kNm kNm

N/mm2 <rom t!e colmn ace) r E 2<&."')) ter E 2
/')@&/4/Jm

nel (i't! E 2 $ &." $ ' m sare mm

<,ale 3.&0 MS +&&0)