Raft Design

CHEC Bearing Capacity =

Tn9: 2

1.8

Qn = LEFT-OS TO-OS

LX-1

DX-1

0

D$-2

! ." #

31 8

0

1"#

!4

#!

1#1

%0

!%

2%2

41 2

0

2""

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

88 4

1 2#

8%#

! ." #

L$-3 D$-3 L$-4

1 # .3 3

D$-4

0

L$-# D$-#

0

L$-! D$-!

0

L$-" D$"

0

L$-8 D$-8

0

L$-% D$-%

0

L$-10 0

TOT&L-L

TOTAL-DY

LX-3

" .0 ! "

L$-2

BOT-OS

DX-2

! ." #

L$-1 D$-1

LX-2

4 .0 3 2

29.147 LE'(T) OF *&FT +,T) OFFSETS/ 

=

# % .2 #

)&LF LE'(T) OF *&FT +,T) OFFSETS/ 2

=

2%.!2#

LE'(T) OF *&FT +,T)OT OFFSETS/ L

=

# % .2 #

)&F LE'(T) OF *&FT +,T)OT OFFSETS/ L2

=

2%.!2#

,DT) OF *&FT +,T) OFFSETS/ y

=

2%.14"

)&LF ,DT) OF *&FT +,T) OFFSETS/ y2

=

14.#"3#

,DT) OF *&FT +,T)OT OFFSETS/ ,

=

2%.14"

)&LF ,DT) OF *&FT +,T)OT OFFSETS/ ,2

=

14.#"3#

 = 56312

=

1 2 2 2 ! 1 .2 1

$ = 65312

=

# 0 # 2 1 ! .! 8

S OF &LL SE*CES LO&DS/ 

=

#0# 1

&*E& OF *&FT/ 5 X 6

=

1 " 2 ! .% # % 8

X7

=

31.1!"%3"

EX = X7 - +L2

=

1 .# 4 2 % 3 "

$ =   EX

""%3.3"#

$ =   EX

""%3.3"#

$7

=

1 4 .4 " " 1 8

E$ = $7 - +,2

=

-0.0%!31%!

 =   E$

- 4 8 ! .# 1 0 #

&

=

-2.%24"%31

+ $ . 2   $

=

0.4#!%8%#

+ X . y2   X

=

-0.0#"%%1%

;1 =-+& - ++ $ . 2   $ - ++ X . y2   X

=

-3.323"%0"

;2 = -+& < ++ $ . 2   $ - ++ X . y2   X

=

-2.40%811"

;3 = - +& < ++ $ . 2   $ < ++ X . y2   X

=

-2.#2#"%##

;4 =-+& - ++ $ . 2   $

E?ec@Ae E?ec@Ae 5earing 9tre99 r t6e 9i

100

S5 gra>e >9

 

20/000

Cncrete 9trengt6  ra:

1!.#

*einrceent 9tee 9trengt6

420

Why Raf should be used  ;e

=

100 '2

ai >ea> a> n cn

=

3#0 '

ai iAe a> n cn

=

2#0 '

Tta ai 9erAice aia a>

=

!00 '

&rea  9inge 9;. @ng

=

!.!0 2

,i>t6  >ept6  t6e @ng

=

2 .# " 

r

3





3



T6i9 area i9 cn9i>ere> t 5e Aery 5ig t 5e ecaAate> ecaAate> 9 ra: i9 re ecnica an> ecient r t6i9 n>a@n

Raf Thi!"ess n ra: ra: n> n>a@ a@n n t6ic t6icne ne99 99 can 5e >ete >eteri rine> ne> 5y c6ec c6ecing ing t6e >iagn >iagna a ten9i ten9in n 96ear 96ear t6at t6at Gi Gi 5e i i t6e ai @ate cn a> Gi 5e 9e> in t6e caca@n.  = +5+>+H+0.34+  +5+>+H+0.34+ c7  = actre> cn a> H = re>c@n actr 5 = t6e perieter  t6e 96eare> area > = e?ec@Ae >ept6  ra: c7 = cpre99iAe 9trengt6  cncrete n t6i9 ra:

>2 =

820 '

=

0.82 '

0.4

= 5 =

0.82 '

0.4

n >iaen9in

1.!

>2



> >2

=

+C%%+>+0."#+0.34+c7

SAe anay an> In> > a:er In>ing > a>> "# r cAer an> 2# r 5ar area CAer =

"#



0.82

=

+C%%>2 a=

= 4

5=

1.!

c=

-0."%2

+C%%>2 1.03! 0."%2

2.302

-#.#02

0.200

-0.!00

>=

300

S t6icne99  ra: =

300

Tae p9i@Ae Aae t  t6e9e tG r J>J



11.81 in

Raf #e$%h he!  One Gay S6ear  =

ai 96ear - +d +w 9i

T >eterine t6e G9i/ t6e aAerage 9i pre99re 96> 5e >eterine> in t6e ai a>9 9trip9 &99e a. Aae  96ear i9 =

21"3 '

r t6e 9trip/ t6e @ate 5earing 9tre99  t6e 9i ;t

=

+Tta actre> a> in 9trip area  t6e 9triparea  9trip 2%%!

44%!

44%4

2%%!

8.3#21 G9i

=

G9i

=

#184.08

>

=

22#

 =

1"%4 '2 ' 

ai 96ear - +d +w 9i 21"3 +d +w 9i

 = >=

100!.! '  +1000

=

+0."#+c7+1!+B >=

!8#.0 

Not OK in one way Punching

TG Gay S6ear

0.#

>2

a

a Cn aia a> - +>=

-41.8 

OK in two way Punching

 & ' s%(i$ desi)"* Posi+,e -o.e"%s /Bo0o. (ei"1o(e.e"%2 >=

22# 

< +a

3".4 '.

<

0.8"

 ! 374.3

r

p9i

H5>2 g t t6e ta5e ρ =  ρ = K +9e> =

0.0088

re t6an

0.0088

e99 t6an

0.0088

&9 =

K5>

&9 =

1%80

Kin =

Ka = 0 .01%

103083#.08%

0.8#c5 a

=

c

=

=

+r !0/000 p9i an> 3/#00

2

C6ec c &9Fy

+r !0/000 p9i an> 3/#00

OK

use 3455 6 73  1o( $osi+,e .o.e"%s i" & di(e+o"' Bo0o. (ei"1o(e.e"% 

a=

0.003#

1402# "3.#0  aB1

8!.4" 

8

735455

.. 9  

= >

=

>

=

Pt

=

8!.4"  6-cAer 22#  M+>-ccN0.003 0.0048

t6en 9e H =



0.00#

+Ten9in Cntr

3".4

'.

0

c

=

H+&9+FyM+> - +a2N

=

0.00 '.



0

 1o( $osi+,e .o.e"%s i" & di(e+o"' Bo0o. (ei"1o

6

73

8

735 

Ne)a+,e -o.e"% /To$ (ei"1o(e.e"%2 >=

22# 

< +a

3".4 '.

<

0.8"

=

H5>2 g t t6e ta5e ρ =

0.00!4

re t6an

 ρ =

0.003#

e99 t6an

K +9e> =

0.00!4

&9 =

K5>

&9 =

1440

 ! 12".0

r Kin =

0.003#

Ka = 0 .01%

p9i

+r !0/000 p9i an> 3/#00 +r !0/000 p9i an> 3/#00

OK

2

use :455 6 73  1o( "e)i+,e .o.e"%s i" & di(e+o"' To$ (ei"1o(e.e"% 

8

355455

.. 9  

C6ec c a=

&9Fy

!18#01.0#3"

0.8#c5 a

=

c

=

1402# 44.10  aB1

= >

=

>

=

Pt

=

#1.88  6-cAer 22#  M+>-ccN0.003 0.0100

t6en 9e H = c



0.00#

+Ten9in Cntr

3".4

'.

0.% =

H+&9+FyM+> - +a2N

=

112.%" '.



OK

 1o( "e)i+,e .o.e"%s i" & di(e+o"' To$ (ei"1o(e

; ' s%(i$ desi)"*

Posi+,e -o.e"%s /Bo0o. (ei"1o(e.e"%2

6

73

8

355 

Posi+,e -o.e"%s /Bo0o. (ei"1o(e.e"%2 >=

200 

< +a

3".4 '.

< H5>2 g t ; ta5e ρ =  ρ = K +9e> =

 ! 1#9.#0

1.10 r

= 0.00%

re t6an

0.003#

e99 t6an

K5>

&9 =

1800

Ka = 0 .01%

+r !0/000 p9i an> 3/#00 +r !0/000 p9i an> 3/#00

OK

0.00%

&9 =

Kin = 0.003#

$%i

2

use

=

>

=

Pt

=

!%.18  6-cAer 22#  M+>-ccN0.003 0.00!8

t6en 9e H = c



0.00#

Ten9in Cntr

3".4

'.

0.% =

H+&9+FyM+> - +a2N

=

14#.1" '.



OK

 1o( $osi+,e .o.e"%s i" ; di(e+o"' Bo0o. (ei"1o

6

73

8

::5 

Ne)a+,e -o.e"% /To$ (ei"1o(e.e"%2 >=

200 

< +a

3".4 '.

< H5>2

1.10

=

g t ; ta5e ρ =

0.00"!

re t6an

 ρ =

0.003#

e99 t6an

K +9e> =

0.00"!

o&

 ! 1#9.#

Kin = 0.003# Ka = 0 .01%

$%i

+r !0/000 p9i an> 3/#00 +r !0/000 p9i an> 3/#00

OK

&9 =

K5>

&9 =

1#20

2

use

- +a2N

=

14#.1" '.



OK

 1o( "e)i+,e .o.e"%s i" ; di(e+o"' To$ (ei"1o(e

'o(ent )a*ue +,N.(( / t&i$ oo( A% To$ A% Y t&i$ oo( A% To$ A%

3".4 3".4 3".4 3".4

6

73

'anua* De%ign H 2#  2#0 mm H 2#  #00 mm H 2# 330 mm H 2# 330 mm

8

::5 

K OF RAFT AREA AGAINST THE BEARING PRESSURE OF SOIL

DX-3

LX-4

DX-4

11.#

LX-#

DX-#

11.#

LX-!

DX-! LX-"

11.#

DX-"

11.2#

LX-8 0

204

22"

188

40#

0

0

0

0

24#

0

0

#10

0

24#

0

23#

2#2

20#

431

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

43%

%8%

3%3

132!

0

OR OR OR OR

'2 '3 a

2/3%3 p9i

a

!0/%1! p9i

9e> in t6e ra:

2

2.8%

a. 96ear 9trip 2.8% 

>2

%42.8!!3

 

cncrete

 

cncrete area +2

H  5ar 10

"8.#

12

113.1

1!

201.1

20

314.2

22

380.1

2#

4%0.%

32

804.2

.. 9 

 

cncrete

 

cncrete

.. 9 

10

"8.#

12

113.1

1!

201.1

20

314.2

22

380.1

2#

4%0.%

32

804.2

 

cncrete

 

cncrete 10

"8.#

12

113.1

1!

201.1

20

314.2

22

380.1

2#

4%0.%

32

804.2

10

"8.#

12

113.1

1!

201.1

20

314 2

.. 9 

 

cncrete

 

cncrete

20

314.2

22

380.1

2#

4%0.%

32

804.2

12

11.81

.. 9 

ent +5-in

*n



2*nFy

*6

33101"."

3"4.3

2%.%

0.3"

0.00!8

33101"."

3"4.3

2%.%

0.3"

0.00!8

33101"."

3"4.3

2%.%

0.3"

0.00!8

33101"."

3"4.3

2%.%

0.3"

0.00!8

DX-8

LX-%

DX-% LX-10

0

TOTAL-D/

*()T-OS TOT&L-L

0

0

#9.2#

0

0

1#1"

0

0

#1!

0

0

120!

0

0

1812

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0 0

0

0

#0#1

#0#1

De%ign o oo5ng% +a6 oo5ng% 

De%ign o oo5ng% +a6 oo5ng%  Laye& A +*o8a* / Di&ec5on - To$ e8a&% *e;ire> reinrceent = *e;ire> era *einrceent = Dia. =

0.#

0.#

inc.2:

0.#

inc.2:

inc

9ing Bar '.

4

&rea  ne 5ar =

'  Bar9 re;. Spacing  Bar9

= =

9ing B ar '.

4

'  Bar9 re;.

=

3

Spacing  Bar9

=

4

9ing Bar '.

4

'  Bar9 re;. Spacing  Bar9

= =

9ing B ar '.

4

'  Bar9 re;.

= =

3 4

inc6 cc

Laye& A +*o8a* / Di&ec5on- oo( e8a&% *e;ire> reinrceent = *e;ire> era *einrceent = Dia. =

0.#

0.#0

inc.2:

0.#

inc2:

inc

&rea  ne 5ar = inc6 cc

Laye&  +*o8a* Y Di&ec5on- To$ e8a&% *e;ire> reinrceent = *e;ire> era *einrceent = Dia. =

0.#

0.!

inc.2:

0.!

inc.2:

inc

&rea  ne 5ar =

3 4

inc6 cc

Laye&  +*o8a* Y Di&ec5on- oo( e8a&% *e;ire> reinrceent =

0.44"! inc.2:

*e;ire> era *einrceent = Dia. =

0.#

0.4

inc2:

inc

Spacing  Bar9

&rea  ne 5ar =

3 #

inc6 cc

'ini(u( eino&ce(ent T6icne99  @ng Sa5 =

18

0.3888 inc.2:

in *einrceent = 0.0018. 5 .6 = 9ing 

#

inc



%

inc6 cc

< < < <

4 4

= = = =

&rea  ne 5ar =

:LT ; *o8a* /- Di&ec5on +To$ *o8a* /-Di&ec5on +ot. *o8a* Y- Di&ec5on +To$ *o8a* Y-Di&ec5on +ot.

A 'ODL

4 4

4 4 4 #

inch cc inch cc inch cc inch cc

0.2 inc.2

0.2 inc.2

0.2 inc.2

0.2 inc.2

0.31 inc.2

 ent   i9 nGn r cacate> r t6e ET&B9 / S&

 ent  i9 nGn r cacate> r t6e ET&B9 / S& >e etc t6en &rea  Stee +& 9  c7 =

3000

psi

 y =

60000

psi

Mu =

19

k-ft

  Bea Dien9in +inc6 >=

18.25

%



21

inch

A&ea o tee* i% gi)en 8y ; As = (0.85.f c ' .b.d/f y  )*(1-(1-(2.Mu /0.9.b.d 2 .0.85f c'  )1/2  ) =

0.24

inch2/ft

ini &rea  Stee = 0.0018.5.6 =  Bar '

4

0.34

inch2/ft

t 5e 9e> / t6en Spacing G> 5e

!.%

inc6 cc

Design Data Fy= Fc'= $p%n= &ie &!%( De%( &!%( M!*ent !efficient +*i( sp%n,= M!*ent !efficient +$upp!"t,=  ssu*e( $ef &!%(= !t% F%ct!"e( &!%(=

60000 2400 Density Of !nc"ete 15 Feets 350 &)/ft 350 &)/Ft 8 10 103.3435 &)/ft 1229.68125 &)/Ft

150 #cf  

Design Solution h! +%,= 0.50 h! +%,= n= )(2=

0.011 0.0086 448.6153 #si 102.894 in3

 F )=  hen (= Depth "eui"e( f!" (efecti!n+sp%

12 inch 9.26 n( h= 11.25 inch

7$ i(th )= :ei;ht h=

12 nch 12 nch

O< in Defecti!n

Steel Calculations  !tt!* !efficient M!*ents +&)-inch, M!*ents + !p

> !tt!*

10

8

10

0

332/014

41#/01"

332/014

D0U

28

28

28

28

450.836315985 360.6690928

?D@/0A

n

360.6690928

*

29.4116406

2*n/Fy

0.353591542

0.441996442 0.353591542

?D@/0A

h!

0.006664281

0.0086021239 0.006664281

?D@/0A

 s

0.5920

0.9806421206 0.5920

?D@/0A

Bar Dia

No. Of Bars

29.41164059 29.4116406 29.41165

No. Of Bars

No. Of Bars

3

6.9

8.9

6.9

4

3.9

5.0

3.9

5

2.5

3.2

2.5

6.0 .0 8.0 9.0 10.0

1. 1.3 1.0 0.8 0.6

2.2 1.6 1.2 1.0 0.8

1. 1.3 1.0 0.8 0.6

Capacity Check of selected section $eecte( (i*ensi!ns )= (= Steel

12 12 4  s= %= #hi Mn=

4 0.9 1.9 402464.0 O<

5 0.98 2.4 488894.6 O<

33.5

4 0.9 1.9 402464.0 &)-inch O<

40.

33.5