Watertank 2

8/9/2019 Watertank 2

1/41

1

Design and drawing of RC

StructuresCV61Dr. G.S.Suresh

Civil Engineering Department

The National Institute of Engineering

Mysore-5 ! !!"

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


2/41

(

WATER TANKS


3/41

&

earning out Come REVIEW

TYPES OF TANKS

DESIGN OF CIRCULAR WATER TANKRESTING ON GROUND WITHFLEXIBLE BASE

DESIGN OF CIRCULAR WATER TANK

RESTING ON GROUND WITH RIGIDBASE


4/41

'

INTRODUCTION

Storage tanks are built for storing water, liquidpetroleum, petroleum products and similar liquids

Designed as crack free structures to eliminate anleakage !ermeabilit of concrete is directl proportionalto water cement ratio"

Cement content ranging from ##$ %g&m # to '#$%g&m# is recommended in order to keep s(rinkagelow"


5/41


6/41

)

R)STIN* ON *ROUND


7/41

UND)R*ROUND


8/41"

)+) -T)D


9/41%

CIRCU+-R


10/411!

R)CT-N*U+-R


11/4111

S!.)RIC-+


12/411(

INT/


13/41

1&

CONIC-+ 0OTTO1


14/41

1'

Circular Tanks Resting On

*round


15/41

15

T(e tank (as tendenc to increase indiameter due to ( drostatic pressureT(is increase in diameter all along t(e(eig(t of t(e tank depends on t(enature of 2oint at t(e 2unction of slab

and wall


16/41


17/41

1

3(en t(e 2oints at base are fle4ible,( drostatic pressure inducesma4imum increase in diameter at baseand no increase in diameter at top3(en t(e 2oint at base is rigid, t(e base

does not mo5e


18/41

1"

Design of Circular Tanks resting on

ground wit( fle4ible base


19/41


20/41

(!

3(en t(e t(ickness 6 77' mm, t(e steel placed atcentre"3(en t(e t(ickness 8 77'mm, at eac( face - st &7 of

steel as (oop reinforcement is pro5idedT(e stress in concrete is computed as

If , ,at / 0here ,at !.( f,2 / then no ,ra,2 appearsin ,on,rete

ststcc

A)1m(t1000

2/HD

A)1m(A

T

+

=

+=


21/41

(1

3(ile designing, t(e t(ickness of concrete wallcan be estimated as t9#$.:'$ mm, w(ere . is inmeters Distribution steel in t(e form of 5ertical bars arepro5ided suc( t(at minimum steel arearequirement is satisfied -s base slab is resting on ground and no

bending stresses are induced (ence minimumsteel distributed at bottom and t(e top arepro5ided


22/41

((

3(ile designing, t(e t(ickness of concrete wallcan be estimated as t9#$.:'$ mm, w(ere . is in

meters Distribution steel in t(e form of 5ertical bars arepro5ided suc( t(at minimum steel arearequirement is satisfied -s base slab is resting on ground and nobending stresses are induced (ence minimumsteel distributed at bottom and t(e top arepro5ided


23/41

(&

!roblem on Circular Tanks resting

on ground wit( fle4ible base


24/41

('

Design a circular water tank wit( fle4ibleconnection at base for a capacit of ;,$$,$$$liters" T(e tank rests on a firm le5el ground"T(e (eig(t of tank including a free board of7$$ mm s(ould not e4ceed #"'m" T(e tank isopen at top" Use 1 7$ concrete and


25/41

(5

Step => Dimension of tank Dept( of water .9#"' ?$"7 9 #"# m

olume 9 ;,$$,$$$&=$$$ 9 ;$$ m #-rea of tank - 9 ;$$"# 9 =7="7 m 7

Diameter of tank =# m

T(e t(ickness is assumed ast 9 #$.:'$9=;@ =A$ mm


26/41

()

Step 7> Design of ertical wall1a4 (oop tension at bottom -rea of steel 1inimum steel to

be pro5ided-st min9$"7;Bof area of concrete

9 $"7;4 =$$$4=A$&=$$ 9 # ; mm 7 T(e steel required is more t(an t(e minimum required+et t(e diameter of t(e bar to be used be =A mm, area of

eac( bar 97$= mm7Spacing of =A mm diameter bar9=;#$4 =$$$&7$=9 =;$"A mm

c&c!ro5ide =A E =;$ c&c as (oop tension steel


27/41

(

Step #> C(eck for tensile stress-rea of steel pro5ided -st

pro5ided97$=4=$$$&=;$ 9 =;#A"=A mm71odular ratio m9Stress in concrete

!ermissible stress cat9$"7F fck9 ="7N&mm7

-ctual stress is equal to permissiblestress, (ence safe"


28/41

("

Step ;> Curtailment of (oop steel>Guantit of steel required at =m, 7m, and

at top are tabulated" In t(is table t(ema4imum spacing is taken an # 4 =A$ 9; $ mm


29/41

(%

Step '> ertical reinforcement>


30/41

&!

Step A> Tank floor>-s t(e slab rests on firm ground,

minimum steel E $"# B is pro5ided"T(ickness of slab is assumed as ='$mm"

mm diameter bars at 7$$ c&c is pro5idedin bot( directions at bottom and top oft(e slab"


31/41

&1


32/41

&(


33/41

&&

Design of Circular Tanks resting on

ground wit( Rigid base


34/41

&'

Due to fi4it at base of wall, t(e upperpart of t(e wall will (a5e (oop tensionand lower part bend like cantile5er"


35/41

&5

T(e e4act anal sis of t(e tank to determinet(e portion of wall in w(ic( (oop tension is

predominant and t(e ot(er portion in w(ic(cantile5er action is predominant, is difficult =" Simplified met(ods of anal sis are7" ReissnerHs met(od#" CarpenterHs simplified met(od;" -ppro4imate met(od'" IS code met(od


36/41

&)

IS code met(odTables @,=$ and == of IS ##F$ part I gi5escoefficients for computing (oop tension,

moment and s(ear for 5arious 5alues of. 7 &Dt.oop tension, moment and s(ear iscomputed as

T9 coefficient w .D&7J19 coefficient w . # J

9 coefficient w . 7 J


37/41

&

Thi,2ness of 0all re3uire4 is ,ompute4 fromM ,onsi4eration

w(ere,

G9 K cbc 2k 29=? kJb 9 =$$$mm

QbMd =

stcbc

cbc

m

mk

+

=


38/41

&"

IS code met(odO5er all t(ickness is t(en computed ast 9 d:co5er"

-rea of reinforcement in t(e form of 5erticalbars on water face is computed as

-rea of (oop steel in t(e form of rings iscomputed as

jdM

Ast

st

=

st1st

TA

=


39/41

&%

IS code met(odDistribution steel and 5ertical steel for outerface of wall is computed from minimum

steel consideration Tensile stress computed from t(e followingequation s(ould be less t(an t(epermissible stress for safe design

st

c A)1m(t1000T

+=

t(e permissible stress is $"7F fck


40/41

'!

IS code met(od

0ase slab t(ickness generall 5ariesfrom ='$mm to 7'$ mm and minimumsteel is distributed to top and bottomof slab"


41/41

Dr. G.S.Suresh

Civil Engineering Department

The National Institute of Engineering

Mysore-5 ! !!"

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

Watertank 2

Documents

Transcript of Watertank 2