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LIMIT STATE METHODOF DESIGN OF

REINFORCED CONCRETE

STRUCTURES

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SCOPE(LIMIT STATE METHOD)

1.VARIOUS LIMIT STATES, DESIGN VALUES, SAFETYFACTORS.

2.LIMIT STATE OF COLLAPSE ITS APPLICATIONSTO DIFFERENT STRUCTURAL MEMBERS.

3.LIMIT STATE OF SERVICEABILITY.

4.PROVISIONS OF IS 45.

5.DESIGN AIDS SP 1

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MAIN MENU

G!"!#$%

&'#"* S+#! M!+-'

U%+/$+! L'$ M!+-'

L/+ S+$+! M!+-'

M!+-' '0 D!*"

Exit

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GENERAL

C% !"*"!!#"* +#+#! $#! $ '/"$+'"'0 +#+#$% !%!/!"+ !$/, '%/", %$,0''+"* !+.

D! +' !+!#"$% %'$ '" +-! +#+#!,0'#! $#! *!"!#$+! " +-!! !%!/!"+ 6--$! !""* $" -!$#. A$% 0'#! $#! $%'*!"!#$+! " '/! !%!/!"+.

D!*" "'%! 7#'"* $ /!/!# '0 $+$%! 8! $" /$+!#$% +' 6+-+$" +-!!0'#!.

Main Menu

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METHODS OF DESIGN

T-!'#!+$%

Main Menu

($) &'#"* S+#! M!+-'

() U%+/$+! L'$ M!+-'

() L/+ S+$+! M!+-'

E7!#/!"+$%

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&OR9ING STRESS METHOD

T- /!+-' $/! +-$+ '+- '"#!+! $"+!!%$+ +'*!+-!# $" $#! !%$+$+$%% +$*!.

I+ $'7+ 7!#/%! +#!! 6-- $#!

!#! : $77%:"* $ 0$+'# '0 $0!+: +' +-!%+/$+! +#!"*+- '0 +-! /$+!#$%. T-! 0$+'#'0 $0!+: 0'# '"#!+! 3 $" 0'# +!!% + 1.;.

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STRESS=STRAIN DIAGRAMS FOR CONCRETEAND STEEL

O

A

BC

Concrete Mild Steel (Fe 250) HYS Bar! (Fe "#5)

OC L"!$# CA E%$+ R$"*! AB P%$+ R$"*!

&S M!+-' '"0"! +!%0 +' +-! %"!$# $" !%$+ #$"*! "'+- '"#!+! $" +!!%.

I"$#$! " !*" $/7+'" '#!##'# " $%%$+'".

I"$#$! " $!"* +-! 7#'7!#+!'0 +-! /$+!#$%.

D!*#!! '0 7!#'", ?$%+: '0

/$+!#$%,!!+'" '0 6'# !+.

P'%! !+!#'#$+'" '0 +-! +#+#!6+- +/!. <

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P#'$%+: $%%$+'" $#! '"! +$"* "+'$'"+ $%% +-! #$"'/ 0$+'# 6-- $" %!$ +'+-! %/+ +$+! +' $##! $+ +-! >

M$*"+! '0 %'$ $"* +-! /'+"0$'#$%! !00!+.

S+#!"*+- '0 /$+!#$%, +-!# ?$%+: $"$#$+'".

D!+!#'#$+'" 6+- 7$$*! '0 +/!. C'! -$ "+#'! -$#$+!#+ $%!!7!""* '" +-! 7!#'" '0 $+$ #!%$+"* +'"+!"+: '0 %'$"* $" +-! +#!"*+- '0 +-!/$+!#$%. I+ +-! $!7+$%! %/+ 0'# +-!

$0!+: $" !#!$%+: '0 $ +#+#! !0'#!0$%#!.

T-! +#+#! -'% ! $%! +' 6+-+$" $%%+-! %'$ %$%! +' $+ '" + +-#'*-'+ + %0!$+0:"* +-! %/+ '0 '%%$7! $ 6!%% $!#!$%+: (!0%!+'" $" #$"*).

T-! $/ +' $-!! $!7+$%! 7#'$%+!- +-$+ +-! +#+#! 6%% "'+ !'/! "0+ 0'#+-! ! 0'# 6-- + "+!"! .!. + 6%% "'+

#!$- + %/+ +$+!. <

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T-! !*" $! '" -$#$+!#+ $%!'0 /$+!#$% +#!"*+-$" +-! $77%! %'$

6-- +$! "+' $'"+ +-! $#$+'" " +-!+#!"*+- '0 +-! /$+!#$% $" +-! %'$ 6--$#! $77%! '" +-! +#+#!.

T-! -$#$+!#+ $%! $#! $! '"+$++$% $+$6-- $#! '+$"! 0#'/

0#!?!": +#+'" #!$%%! G$$"D+#+'" C#!.

B$%$"! S!+'"

C$! 2> U"!# #!"0'#! S!+'"

C$! 3> O!# R!"0'#! S!+'"

C$! 4> D'%: R!"0'#! S!+'"

5

0-002?0-@+;E!

0-002

0-"5+c,

>xu;30-">xu"xu;30-5xu

0-"2xu

C 3 0->7+c, xu &

3 0-@+ A!t

Cro!! Section Strain ia$ra% Stre!! ia$ra%

STRAIN AND STRESS DIAGRAMS

3 d D 0-"2xu

BALANCED SECTION

D!7+- '0 N!+#$% A 0'# B$%$"! S!+'" ( ,/$)

!#! 0#'/ >

y

u

f

Es

d

x

87.00055.0

0035.0max,

+

=

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L/+"* $%! '0 7!#!"+$*! '0 +!!% 0'#00!#!"+ *#$! '0 '"#!+! $" +!!%>

y

cku

tf

f

d

xp

max,

lim, 4.41=

+c,/tli%+or +3

250 "#5 500

#5 #-#>7 0-#@ 0-5#20 #-55 0-5@ 0-72

25 2-#" #-# 0-52

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L/+"* $%! '0 M'/!"+ '0 R!+$"! '0B$%$"! S!+'">

2max,max,

lim, 42.0136.0 bdfd

xd

xM ckuu

u

=

F'# F! 25J M,%/ J.14; 02

F'# F! 415 M,%/ J.13; 02

F'# F! 5JJ M,%/ J.133 02

( )max,umax,ucklim,u x42.0dbxf36.0M =

Sol*ero&le%

Menu S

UNDER (SINGLY) REINFORCED SECTION

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UNDER (SINGLY) REINFORCED SECTION

S!+'" "!# #!"0'#! 0 +!!% ('# $#!$'0 +!!%) 7#'! %! +-$" +-$+ #!?#! 0'#+-! $%$"! !+'" .!.

7+K 7+,%/ '# A+K A+,%/

d

&

A!t

xu%ax

0-00>5

0-002?0-@+;E!

0-"5+c,

0-"2xu

C 3 0->7+c, xu &

3 0-@+ A!t

Cro!!Section Strain ia$ra% Strain ia$ra% Stre!! ia$ra% Balanced Sec Gnder ein+ Sec

$%%$+"* 0#'/ +-! ?$#$+ !?$+'" !%'6>( )uucku x42.0dbxf36.0M = $"

=

2ck

u

y

ckst

bdf

M6.411bd

f

f

2

1A

Menu S

Sol*ero&le%

OVER REINFORCED SECTION

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OVER REINFORCED SECTION

S!+'" '!# #!"0'#! 0 +!!% ('# $#!$'0 +!!%) 7#'! /'#! +-$" +-$+ #!?#! 0'#

+-! $%$"! !+'" .!.7+ 7+,%/ '# A+ A+,%/

TO AVOID COMPRESSION FAILURE OF CONCRETE,&E NEVER PROVIDE AN OVER REINFORCED SECTION.

IMPORTANT>IN THE ABOVE CIRCUMSTANCES, THELOAD ON THE STRUCTURE HAS TO BE RESTRICTEDSUCH THAT IT DOES NOT GENERATE A MOMENTMORE THAN THE MOMENT OF RESISTANCE OF THEBALANCED SECTION. Menu SSol*e

ro&le%

DOUBLY REINFORCED SECTION

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I0 +-! !*" /'/!"+ $+"* '" +-! !+'" /'#! +-$" +-! /'/!"+ '0 #!+$"! '0 +-!

$%$"! !+'", +-! !+'" #!?#! +' !!*"! $ $ '%: #!"0'#!!+'".

M M,%/ M,%/ M1

T!"%! +!!% (A+1) 7#'! 0'# +-!$%$"! /'/!"+ M1.

A+'"$% +!"%! (A+2) $" '/7#!!+!!%(A) $#! 7#'! +' #!+ +-! /'/!"+ M2.!

/'/!"+ " !! '0 M,%/

DOUBLY REINFORCED SECTION

!c

http://var/www/apps/conversion/tmp/scratch_1/C:%5CCBTLimSt%5CRectBm.exehttp://var/www/apps/conversion/tmp/scratch_1/C:%5CCBTLimSt%5CRectBm.exe

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d

&

A!t

xu

0-00>5

0-002?0-@+;E!

0-002

0-"5+c,

>xu;30-">xu"xu;30-5xu

0-"2xu

C 3 0->7+c, xu &

3 0-@+ A!t

Cro!!Section Strain ia$ra% Stre!! ia$ra%

3 d D 0-"2xu

A!c

STRESS=STRAIN DIAGRAMS

!c

d

A#!$ '0 '/7#!'"+!!%>

2st1stst AAA +=

sc

2stysc

f

Af87.0A =

OR

Menu S

Sol*ero&le%

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FLANGED BEAMS> T AND L BEAMS

I"+!#/!$+! !$/ ( T B!$/)

E*! B!$/ ( L B!$/)

<

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b"

&"

b'

d

Ast

c=0.0035

u

s

0.00

0.45"ck

T=0.*+"ckAst

C 0.43u

0.5+u

NA

Cross Sec Strain Diag Stress Diag

CASE 1> K D0 .!. N!+#$% A " +-! F%$"*!.

CASE 2> D0 K 3 .!. J.43 '# D03 '# D0 K J.2CASE 3> D0 3 .!. J.43 '# K D03 '# D0 J.2

I" $%% $'! $! K ,/$ .!. !+'" "!# #!"0'#!

CASE 4> ,/$ .!. '%: #!"0'#! !+'"

D0 3 .!. J.43 '# K D03 '# D0 J.2

.!0%$"*! " +-! 7$#$'% 7'#+'" '0 +-! +#!%'.

T' $%%$+! M,%/ 0'# $ !+'", +++! 6+-,/$ " +-! 0'#/%$ *!" !%'6.

$%%$+! : +#$% $" !##'# : '%"* +-!?$#$+ !?$+'" $" +++"* +-! $%! '0 :0 $

*!" !%'6. A%+!#"$+!%:, $" ! $%%$+! : +++"* M

6+- M $" !7#!"* :0 " +!#/ '0 $" '%"*+-! ?$#$+ !?$+'".

( ) ( ) ( )ff"fckuu"cku y5.0dybbf45.0x42.0dxbf36.0M +=

flan$%t&%'ft&ickn%ssM'difi%dyf =

ffu ##65.0x15.0 +=

D'%: #!"0'#! !+'"

I0 D!*" M'/!"+(M) M,%/, +-!!+'" +' ! !*"! $ $ D'%:R!"0'#! !+'".

T!"%! +!!% (A+1) 7#'! 0'# +-!

$%$"! /'/!"+ (M1 M,%/).

A+'"$% +!"%! (A+2) $" '/7#!!+!!% (A) $#! 7#'! +' #!+ +-!/'/!"+ M2 .! /'/!"+ " !! '0M,%/

M2 M M1 A+ A+1 A+2

<

( )

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Menu SSol*e

ro&le%

( )

y

f"fcku"ck1st

f87.0

ybbf45.0xbf36.0A

+=

A#!$ '0 +!!% 0'#B$%$"! S!+'"

A+'"$% A#!$ '0+!"%! +!!%

T'+$% +!"%! +!!%

A#!$ '0 C'/7#!'"+!!%

( )ddf87.0

MA

y

2u2st

=

2st1stst AAA +=

( )ddfscMA 2usc

= 6-!#! 0 $%%$+!$ " R!+$"*%$# B!$/

Exit

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