Watertank 3

8/18/2019 Watertank 3

1/40

1

Design and drawing of RC

StructuresCV61

Dr. G.S.Suresh

Civil Engineering Department

The National Institute of Engineering

Mysore-5! !!"

Mo#$ %&'(1""')Email$ gss*nie+yahoo.,om


2/40

(

WATER TANKS


3/40

&

earning out Come

• REVIEW

• DESIGN OF CIRCULAR WATER TANK

RESTING ON GROUND WITH RIGID

BASE


4/40


5/40

5

Tan/ 0ith flei#le #ase

Tan/ 0ith rigi2 #ase


6/40

)

Design of Circular Tanks resting on

ground with Rigid base


7/40

Due to fixity at base of wall, the upper

part of the wall will have hoop tension

and lower part bend like cantilever

!or shallow tanks with large diameter, hoop

stresses are very small and the wall act morelike cantilever

!or deep tanks of small diameter the

cantilever action due to fixity at the base issmall and the hoop action is predominant


8/40

"

The exact analysis of the tank todetermine the portion of wall in whichhoop tension is predominant and theother portion in which cantilever

action is predominant, is difficult "implified methods of analysis are

# Reissner$s method

% Carpenter$s simplified method& 'pproximate method

( )" code method


9/40

%

)" code method

Ta#les %31! an2 11 of IS &&! part I4gives ,oeffi,ients for ,omputing hooptension3 moment an2 shear for various

values of (6Dt oop tension3 moment an2 shear is

,ompute2 as

T7 ,oeffi,ient 8 γ 0D6(9M7 ,oeffi,ient 8γ 0&9

47 ,oeffi,ient 8γ 0(9


10/40

1!

Thi,/ness of 0all re:uire2 is ,ompute2

from ;M ,onsi2eration

0here3

/

>71-8/6&9

# 7 1!!!mm

Qb

Md =

stcbc

cbc

m

mk

σ+σ

σ=


11/40

11

)" code method

?ver all thi,/ness is then ,ompute2 as

t 7 2@,over.

Area of reinfor,ement in the form of

verti,al #ars on 0ater fa,e is ,ompute2

as

Area of hoop steel in the form of rings is

,ompute2 as

jd

MA

st

stσ

=

st

1st

TA

σ=


12/40

1(

)" code method

Distribution steel and vertical steel for

outer face of wall is computed from

minimum steel consideration

Tensile stress computed from the

following e*uation should be less than

the permissible stress for safe design

st

cA)1m(t1000

T

−+

=σ

the permissible stress is +% √fck


13/40

1&

)" code method

-ase slab thickness generally varies

from #.+mm to %.+ mm and minimum

steel is distributed to top and bottom

of slab


14/40

1'

Design /roblem 0o# on Circular Tanks

resting on ground with Rigid base


15/40

15

' cylindrical tank of capacity ,++,+++ liters isresting on good unyielding ground The depthof tank is limited to .m ' free board of &++

mm may be provided The wall and the baseslab are cast integrally Design the tank using1%+ concrete and !e(#. grade steel

Draw the following

/lan at baseCross section through centre of tank


16/40

1)

"tep #2 Dimension of tank

34 .5+& 4 ( and volume 6 4 ++ m&

'4++7( 4 #(89( m%

D4 √:( x #(89(7 ; 4 #& ≈#( m


17/40

1

"tep %2 'nalysis for hoop tension andbending moment


18/40

1"

"tep %2 'nalysis for hoop tension and bendingmoment :Contd;

Tmax4+.. x #+ x ( x 4#89#. k0

Referring to table #+ of )"&&+ :part )6;,the maximum coefficient for

bending moment 4 5++#(> :producestension on water side;

1max4 ++#(> x #+ x (&4#.#. k05m


19/40

1%

"tep &2 Design of section2

!or 1%+ concrete cbc4, !or !e(#. steel

st4#.+ 1/a and m4#&&& for 1%+concrete and !e(#. steel

The design constants are2

j4#5:k7&;4+8

?4 @ cbcjk 4 ##9Affective depth is calculated as

mm94.1121000x19.1

10x15.15

Qb

Md

6

===

39.0m

mk

stcbc

cbc=

σ+σ

σ=


20/40

(!

"tep &2 Design of section2 :Contd;Bet over all thickness be %++ mm with effective cover&& mmdprovided4#> mm

"pacing of #> mm diameter bar 4

:1ax spacing &d4.+#mm;/rovide #>%. c7c as vertical reinforcement onwater face

26

st

st mm16.695167x87.0x150

10x15.15

jd

MA ==

σ

=

c/mmc23.28916.6951000x201 =


21/40

(1

"tep &2 Design of section2 :Contd;

3oop steel2

"pacing of #% mm diameter bar 4

/rovide #%8+ c7c as hoop reinforcement on water face

'ctual area of steel provided

23

st

1st mm1261150

10x275.189TA ==

σ=

c/mmc.891261

1000x113=

2

st mm5.141280

1000x113A ==


22/40

((

"tep (2 Check for tensile stress2

/ermissible stress 4 +%√fck4#% 07mm% E c "afe

23

st

c mm/ N87.05.1412x)133.13(200x1000

10x275.189

A)1m(t1000

T=

−+

=

−+

=σ


23/40

(&

"tep .2 Distribution "teel2

1inimum area of steel is +%(F of concrete area

'st4:+%(7#++; x#+++ x %++ 4 (8+ mm%

"pacing of 8 mm diameter bar 4

/rovide 8 #++ c7c as vertical and horiGontal

distribution on the outer face

c/mmc.7.104480

1000x24.50=


24/40

('

"tep .2 -ase slab2

The thickness of base slab shall be #.+ mm The baseslab rests on firm ground, hence only minimumreinforcement is provided

'st4:+%(7#++; x#+++ x #.+ 4 &>+ mm%

Reinforcement for each face 4 #8+ mm%


/rovide 8 %.+ c7c as vertical and horiGontaldistribution on the outer face

c/mmc.279180

1000x24.50=


25/40

(5


26/40

()

Design /roblem 0o% on Circular Tanks

resting on ground with Rigid base


27/40

(

Design a circular water tank to hold

.,.+,+++ liters of water 'ssume rigid

joints between the wall and base slab

'dopt 1%+ concrete and !e (#. steel

"ketch details of reinforcements


28/40

("

"tep #2 Dimension of tank

6olume of tank 64..+ m&

'ssume 34 (.

'4..+7(. 4 #%%%% m%

D4 √:( x #%%%%7 ; 4 #%( ≈#%. m


29/40

(%

"tep %2 'nalysis for hoop tension andbending moment


30/40

&!

"tep %2 'nalysis for hoop tension and bendingmoment :Contd;Tmax4+.. x #+ x (. x >%. 4#>#% k0

Referring to table #+ of )"&&+ :part )6;, themaximum coefficient for bending moment4 5++#(> :produces tension on water side;

1max4 ++#(> x #+ x (.&4#&& k05m


31/40

&1

"tep &2 Design of section2Bor M(! ,on,rete σ,#,73 Bor Be'15 steel σst715! Ma

an2 m71&.&& for M(! ,on,rete an2 Be'15 steel

The 2esign ,onstants are$

>71-8/6&97!."

/ 7 1.1%Effe,tive 2epth is ,al,ulate2 as

39.0m

mk

stcbc

cbc=

σ+σ

σ=

mm7.1051000x19.1

10x3.13

Qb

Md

6

===


32/40

&(


Bet over all thickness be %++ mm with effectivecover && mmd

provided4#> mm

"pacing of #> mm diameter bar 4

:1ax spacing &d4.+#mm;

/rovide #>&++ c7c as vertical reinforcementon water face

26

st

st mm27.610167x87.0x150

10x3.13

jd

MA ==

σ=

c/mmc36.32927.610

1000x201=


33/40

&&


3oop steel2

"pacing of #% mm diameter bar 4

/rovide #%#++ c7c as hoop reinforcement on waterface

'ctual area of steel provided

23

st

1st mm13.1078150

10x72.161TA ==

σ=

c/mmc10413.1078

1000x113=

2

st mm1130100

1000x113A ==


34/40

&'

"tep (2 Check for tensile stress2

/ermissible stress 4 +%√fck4#% 07mm% E c "afe

23

st

c mm/ N76.01130x)133.13(200x1000

10x72.161

A)1m(t1000

T=

−+=

−+=σ


35/40

&5

"tep .2 Distribution "teel2

1inimum area of steel is +%(F of concrete area

'st4:+%(7#++; x#+++ x %++ 4 (8+ mm%


/rovide 8 #++ c7c as vertical and horiGontal

distribution on the outer face

c/mmc.7.104480

1000x24.50=


36/40

&)

"tep .2 -ase slab2

The thickness of base slab shall be #.+ mm The baseslab rests on firm ground, hence only minimumreinforcement is provided

'st4:+%(7#++; x#+++ x #.+ 4 &>+ mm%

Reinforcement for each face 4 #8+ mm%


/rovide 8 %.+ c7c as vertical and horiGontaldistribution on the outer face

c/mmc.279180

1000x24.50=


37/40

&


38/40

&"

' TH/)C'B DR'W)0I


39/40

&%


40/40

'!

Dr. G.S.Suresh

Civil Engineering Department

The National Institute of Engineering

Mysore-5! !!"

Mo#$ %&'(1""') Email$ gss*nie+yahoo.,om

Date post:	07-Jul-2018
Category:	Documents
Upload:	anonymous-mpjkdxf
View:	221 times
Download:	0 times

Watertank 3

Documents