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Economics of R.C.C. Water tank Resting over Firm Ground vis-

a-vis Pre-stressed Concrete Water Tank Resting over Firm

Ground

Posted in Concrete Engineering, Prestress Engineering, Project Reports, Research Papers | Email This Pos t |

By

MS. SNEHAL R. METKAR

(P.G. STUDENT)

DEPARTMENT OF CIVIL ENGINEERING

(STRUCTURAL ENGINEERING IIND YEAR)

P.R.M.T OF TECH. & RESEARCH, BADNERA-AMRAVATI

SANT. GADGE BABA (AMARAVATI) UNIVERSITY (MAHARASHTRA)COUNTRY INDIA 444701

GUIDED BY

Prof A. R. Mundhada

(PROFESSOR)

DEPARTMENT OF CIVIL ENGINEERING,

P.R M.I.T.R., BADNERA, AMRAVATI.

MAHARASHTRA, INDIA-4444701,

Abstract

Water tanks are used to store water and are designed as crack f ree st ructures, to eliminate any leakage. In

this paper design of two types o f circular water tank resting on ground is presented. Both reinf orced

concrete (RC) and prest ressed concrete (PSC) alternatives are considered in the design and are compared

considering the to tal cost of the tank. These water tank are subjected to the same type of capacity and

dimensions . As an objective f unction with the properties o f tank that are tank capacity, width &length etc.

A computer program has been developedf or solving numerical examples using the Indian std. Indian

Standard Code 456-2000, IS-3370-I,II,III,IV & IS 1343-1980. The paper gives idea f or saf e design with

minimum cos t o f the t ank and give the designer the relationship curve between design variable thus design

of tank can be more economical ,reliable and simple. The paper helps in understanding the design

philosophy fo r the saf e and economical design of water tank.

Keywords

Rigid based water tank, RCC water t ank, Prest ressed Concrete, des ign, details, minimum to tal cos t, tank

capacity

I. INTRODUCTION

Storage reservoirs and over head tanks are used to s to re water, liquid petro leum, petro leum products and

similar liquids. The force analysis of the reservo irs or tanks is about the same irrespective of the chemical

nature of the product. In general there are three kinds o f water tanks- tanks rest ing on ground Underground

tanks and elevated tanks. Here we are studying only the tanks res ting on ground like clear water reservoirs,

set tling tanks, aeration tanks etc. are support ed on ground directly. The wall of these tanks are subjectedto pressure and the base is subjected to weight o f Water.
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In this paper, both types o f reinforced concrete and prestesses concrete water tanks resting on ground

mono lithic with the base Are design and their results compared. These tanks are subjected to Same

capacity and dimensions. Also a computer program has been developed f or so lving numerical examples

using IS Code 456-200IS-1343-1984,IS 3370-Part I,II,III,IV 1965 & IS Code 1343- 1980. From the analysis it is

conclude that f or t ank having larger capacity (greater than 10 lakh liter) prestesses concrete water tank is

economical.

Objective

To make the study about the analysis and design of water tank. To make the guidelines f or t he design of liquid retaining st ructure According to IS code.

To know about design philosophy for safe design of water tank.

To develop program fo r water tank to avoid tedious calculations.

To know econo mical design of water

This report is to provide guidance in the design and construction o f circular priestesses concrete using

tendons

Previous Research

From the review of earlier investigat ions it is f ound that cons iderable work has been done on the method

of analysis and design of water tanks.

Tanetal. [1]:- (1993) presented the minimum cos t design of reinforced concrete cylindrical water tanks

based on the British Code f or water tanks, using a direct search metho d and the (SUMT). The cost

f unction included the material costs o f concrete and steel only. The tank wall thickness was idealized with

piecewise linear slopes with t he maximum thickness at the base.

Thakkar and Sridhar Rao [2] (1974), discussed cost opt imization of non cylindrical compos ite type

prestressed concrete pipes based on the Indian code.

Al-Badri [3] (2005) presented cost optimizat ion o f reinf orced co ncrete circular grain silo based on the ACI

Code (2002). He proved that the minimum cost o f the silo increases with increasing of the angle of internal

f riction between sto red materials, the coef f icient o f f riction between sto red materials and concrete, and

the number of columns support ing hopper . Al-Badri (2006) presented the minimum cost des ign of

reinforced concrete corbels based on AC I Code (2002). The cost f unction included the material cos ts of

concrete, f ormwork and steel reinforcement. He proved that the minimum to tal cost o f the corbel increases

with the increase of the shear span, and decreases with the increase o f the f riction f actor f or monolithic

construction.

Hassan Jasim Mohammed [4] studied the economical design of concrete water Tanks by optimizat ion

method. He applied the opt imization technique to the s tructural design of concrete rectangular and circular

water tank, considering the to tal cost o f the tank as an objective f unction with the properties o f the tank

viz. tank capacity, width and length o f the tank, unit weight o f water and tank f loo r slab thickness as designvariables. From the study he concluded that an increased tank capacity leads to increased minimum total

cost of the rectangular tank but decreased minimum to tal cost f or t he circular tank. The tank floor s lab

thickness constitutes the minimum to tal cost f or two t ypes o f tanks. The minimum cost is more sensitive to

changes in tank capacity and f loo r slab thickness of rectangular tank but in circular type is more sens itive

to change in all variables. Increased tank capacity leads to increase in minimum total cost. Increase in water

depth in circular tank leads to increase in minimum total cost .


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Abdul-Aziz & A. Rashed [5] rat ionalized the design procedure f or reinf orced and prestressed concrete

tanks so that an applicable Canadian design standard could be developed. The study investigates the

concept o f partial prestressing in liquid containing structures. The paper also includes experimental and

analytical phases o f to tal of eight full scale specimens, representing segments f rom typical tank walls,

subjected to load and leakage tests . In analytical study a computer model that can predict the respo nse o f

tank wall segments is described and calibrated against the test results . The proposed design procedure

addresses the leakage limit st ate directly. It is applicable f or f ully prestressed, f ully reinfo rced and partially

prestressed concrete water tanks. The conclusions that are drawn are as f ollows:-

A design method based on limiting the steel stress, does not produce consistent crack or compression

zone depths under the application of prestressing nor under a combination o f axial load and moment.

A design method based on providing a residual compressive stress in concrete dose not ut ilizes non-

prestressed reinforcement ef f ectively.

Relaxing the residual compressive st ress requirement permits a more ef f icient design. The stresses in

non- prest resssed steel are higher, but remain below yield under service load. Theref ore, less reinf orcement

is required.

Load eccentricity s ignif icantly aff ects t he behavior of the prestressed concrete sections. The behaviorwith a small load eccentricity, less than about half the thickness, the section may be treated as a f lexure

member.

The ratio o f non prestressed steel to prest ressed steel in partially prestressed concrete section has a

signif icant ef f ect on the member serviceability and strength. Choosing the ratio such that both non-

prestress and prestressed steel reach their st rength simultaneously utilizes both types of steel at the

ultimate limit st ate ef f ectively.

Increasing the wall thickness is very ef f ective in increasing the capacity of the section and improving its

serviceability by increasing the compression zone depth and reducing the deformations.

Chetan Kumar Gautam [6] Highlights the po int named Compariso n of Circular Reinf orced Concrete and

Prestressed Concrete Underground Shelter. In his paper, design of two types o f large circular underground

shelters is presented. The shelters are made of precast concrete sections. Both RC and PSC alternat ives

are considered in the design and compared. The shelters are subjected to same type of external loadings

and support conditions. The s tudy conclude that the f easibility of using the vertical casting process o f

making the modules of shelters as it is suitable for manufacturing of large diameter pipes. He also

suggested that the incorporation of f ibers, specially steel f ibers improves a host o f properties of concrete,

including its crack resistance, f lexural strength, ductility, etc. Thus, the poss ibility of incorporat ing f ibers in

concrete shelter may be explored.

II DESIGN PHILOSOPHY

For R.C.C. water tank

For Prestresed Concrete water tank

For R.C.C Structure

Permissible stresses in concrete

For resistance to cracking:-

Design of liquid retaining structure is dif f erent f rom R.C.C. st ructures. As it requires that concrete should

not crack and hence tensile st resses in concrete sho uld be within permissible limit.(i.e. TYPE-I structure).A

reinforced concrete member of liquid retaining st ructure is design on the usual principle ignoring tensile

resistance of concrete in bending. accordingly it should be ensure that tensile stresses o n the liquid

retaining face of the equivalent concrete section dose not exceed the permissible tensile strength o f

concrete as given in table1.

Grade ofconcrete

Permissible stress Shear=(Q/bjd)(N/mm^2)


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Direct Tension(?ct)(N/mm^2)

Tension due to Bending(?cbt)(N/mm^2)

M15 1.1 1.5 1.5

M20 1.2 1.7 1.7

M25 1.3 1.8 1.9

M30 1.5 2.0 2.2

M35 1.6 2.2 2.5

M40 1.7 2.4 2.7

Table 1(Permissible Compressive Stresses In Calculations Relating To Resistance To Cracking)

For strength calculation

In st rength calculations the permissible Concrete s tresses shall be in accordance with Table1. Where the

calculated shear s tress in concrete a lone exceeds the permissible value, reinfo rcement acting in

conjunction with diagonal compression in the concrete shall be provided to take the whole of the shear.

Permissible Stresses In Steel

For resistance to cracking.

When steel and concrete are assumed to act to gether for checking the tensile st ress in concrete f or

avoidance of crack, the tens ile st ress in steel as in table 2will be limited by the requirement that the

permissible tensile stress in the concrete is not exceeded so the tensile stress in steel shall be equal to the

product of modular ratio o f steel and concrete, and the corresponding allowable tensile stress in concrete.

For strength calculations

In st rength calculations the permiss ible st ress shall be as given in table 2.

TYPE OF STRESS IN STEEL REINFORCE MENT PERMISSIBLE STRESSES IN N/mm2

Plain ro und mildsteel bars

High yield strength deformedbars(HYSD)

1)Tensile stresses in the members under directtension(?s)

115 150

2) Tensile st ress in members in bending(?st)

On liquid retaining f ace of members 115 150

On face of away f rom liquid f or members lessthan 225mm

115 150

On face away f rom liquid f or members 225mm ormore in thickness

125 190

3) Tensile st resses in shear reinforcement(?sv)

For members less than225mm in thicknessFor members 225mm or more in thickness

115 150

125 175

Table 2 (Permissible Stresses In Steel Reinfo rcement For Strength Calculation)


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Design Requirement

Generally M30 grade o f concrete should be used Design Mix (1:1*1/2:3)Steel reinf orcement sho uld not less

than0.3% of the gross section shall be provided in each direction Floo rs:-f loor may be constructed o f

concrete with nominal % of reinforcement smaller than provided in table 1.they are cast in panels with s ides

not more than 45m and with contract ion o r expansion joints in between..In such cases a screed or concrete

layer(M10) not less than 75mm thick shall placed f irst on the gro und and covered with a sliding layer of

bitumen paper to destroy the bond between the screed and the f loor.

Minimum Cover:- 35mm(both the faces).Minimum Reinf orcement:-Overall .24% of to tal cross section should be provided.

Walls:-1) provision of joints

( a ) Where it is desired to allow the walls to expand or contract separately f rom the f loor , o r to prevent

moments at the base of the wall owing to f ixity to the f loor sliding joints may be employed.

( b) The spacing of vertical movement joints should be as discussed. while the majority of these joints may

be of the partial or complete contraction type , suf f icient joints of the expansion type should be provided

to sat isf y the requirements given in article.

2)Pressure on wall(a) In liquid retaining structures with f ixed or f loat ing covers t he gas pressure developed above liquid

surf ace shall be added to the liquid pressure .

(b)When the wall of liquid retaining structure is built in ground, or has earth embanked against it ,the ef f ect

of earth pressure shall be taken in to account .

III Design stepes:

Calculate diameter and height o f water tank

Assumed suitable thickness

Calculate designed constants

Calculate hoop tensio n, maximum bending moment by using IS 1370 part IV.

Calculate hoo p steel(provide in the form of rings per meter height)

Check the assume thickness with given permissible values o f tensile st resses o f concrete in direct

tension f or the given grade of concrete.

Check of thickness f or bending

Provide vertical steel

Design base slab

Draw details


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detail

IV PRESTRESSING DEFINITION

Introduction o f compressive st resses to a st ructural member with high-s trength steel that counteract the

tensile stresses resulting f rom applied loads

Prestressed Concrete

Pre-Tensioned (cast o f f -s ite in beds- precast members)

Pos t-Tensioned (cast on-site in place)

All types of st ructure can be built with reinf orced and pre-stressed concrete: columns, piers , walls, slabs,beams, arches, f rames, even suspended st ructures and o f course shells and f olded plates.

Tanks

Foundat ion panels

Poles

Modular block retaining wall system

Wall panels

Concrete units

Slabs

Roofing and flooring

Lintel and sunshade

Beams

Columns girders

Tanks:-

In the construction of concrete st ructures f or the sto rage of liquids, the imperviousness o f concrete is an

important basic requirement. Hence, the design of such const ruction is based on avoidance of cracking in

the concrete. The s tructures are prestressed to avoid tension in the concrete. In addition, prestressed

concrete tanks require low maintenance. The resistance to seismic f orces is also sat isf actory. Prestressed

concrete tanks are used in water treatment and distribution systems, waste water collection and treatment

system and sto rm water management. Other applications are liquef ied natural gas (LNG) containment

st ructures, large industrial process tanks and bulk sto rage tanks. Strand Wrapped circular pre-s tressedconcrete tanks are long lif e liquid sto rage structure with virtually no maintenance. Concrete cons truction

makes f or a substantial, sturdy tank structure that easily contain the internal liquid pressure while

comfort ably resist ing external f orces such as earthquake, wind.


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Pre-st ressed concrete is the most ef f icient material fo r water tanks and coupled with the circular shape,

eliminates all stress conditions. By placing the steel o f the pre-s tressed st rands in tension and the

concrete in compression, both materials are in an ideal states and the loads are unifo rmly distributed

around the tank circumf erence.

Properties

1) Low maintenance can be enjoyed througho ut the lif e as these are built with concrete, durable material

that never corrodes and does not require coatings when in contact with water or the environment.

2) Pre-s tress ing counteracts the dif f erential temperature and dryness loads that a t ank core wall

experience. The tank walls are wet on the inside and dry on outs ide and the temperature varies between the

two sides. If not properly accounted f or, these moisture and temperature dif f erential will cause a tank wall

to bend and crack. Counteract these f orce in both the vertical and horizo ntal direction and diminish

subsequently the cracking and leaking

3) Tanks are very ductile, enabling to withs tand seismic forces and varying water backf ill.

4) Tanks utilize material ef f iciently st eel in tension, concrete in compress ion

5) Pre-cast tanks can store or treat anything f rom potable water to hazardous waste to so lid sto rage bins.

6)Storage capacities can range f rom 0.4 to 120 mega liters

7) Diameters of the tank can vary up to 90 m

V Design philoso phy

A. Loads: Circumferential pres tressing also typically causes vert ical bending moment f rom other lo ading

condition.

B. Freeboard: f reeboard should be pro vided in the tank wals to minimize earthquake- induced hydrodynamic

eff ects on a f lat roof .

C. Wall: The design of the wall should be based on elastic cylindrical shell analysis, considering the ef f ects

of prestress ing, internal loads and other external loads.cast in place concrete walls is usually priestessescircumf erentially with high-st rength strand tendons placed in ducts in the wall .the wall may be priestesses

with bonded and unbounded tendons. Vertical prestessed reinfo rcement near the center o f the wall

thickness, or vert ical non prestessed reinforcement near each f ace, may be used. Non priestesses

reinforcement may be provided vertically in conjunction with vert ical prest ressing.

Precast concrete walls usually consist o f precast panels curved to the tank radius with joints between

panels f illed with high-st rength concrete. the panels are post -tens ioned circumferentially by high strength

st rand tendons . the tendons maybe embedded within the precast panels or placed on the external surface

of the wall and protected by short creat .the wall panels may be prestessesd vertically with pretensioned

st rands or post -t ensioned tendons.non prestesses reinf orcement may be provided vertically with or

without vertical prestressing.


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Construction Methodology

The construction o f the tanks is in the f ollowing sequence. First, the concrete core is cast and cured. The

surf ace is prepared by sand o r hydro blast ing. Next, the circumf erential prestressing is applied by strand

wrapping machine. Shotcrete is applied to provide a coat o f concrete over the prestressing strands. A f ew

photo graphs are provided for illustration.

IS: 3370 (Code o f Practice f or Concrete Structures f or the Storage o f Liquids) provides guidelines f or the

analysis and design of liquid sto rage tanks. The four sections o f the code are titled as f ollows.

Part 1: General Requirement

Part 2: Reinforced Concrete Structures

Part 3: Prest ressed Concrete Structures

Part 4: Design TablesThe fo llowing types of boundary conditions are considered in the analysis of the cylindrical wall.

a) For base: fixed or hinged

b) For to p: f ree or hinged or f ramed.

1)For base

Fixed: When the wall is built continuous with its f oot ing, then the base can be considered to be f ixed as the

f irst approximation.


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Hinged: If the sub grade is susceptible to set tlement, then a hinged base is a conservative assumption.

Since the actual rot ational rest raint f rom the f oot ing is so mewhere in between f ixed and hinged, a hinged

base can be assumed. The base can be made sliding with appropriate polyvinyl chloride (PVC) water-stops

f or liquid tightness.

2) For top

Free: The top of the wall is considered f ree when there is no rest raint in expansion.

Hinged: When the top is connected to the roo f slab by dowels f or shear transf er, the boundary condition is

considered to be hinged.

The hydrostatic pressure o n the wall increases linearly f rom the to p to the bot tom of the liquid o f maximum

poss ible depth. If the vapour pressure in the f ree board is negligible, then the pressure at the to p is zero .

Else, it is added to the pressure o f the liquid throughout the depth. The f orces generated in the tank due to

circumf erential prestress are oppos ite in nature to that due to hydrost atic pressure. If the tank is built

underground, then the earth pressure needs to be considered.

The hoop tension in the wall, generated due to a triangular hydrostatic pressure is given as T = CTw H Ri

The bending moment in the vert ical direction is given as

M = CMwH3

The shear at the base is given by the expression V = CVw H

Where,

CT = coeff icient f or hoop tension

CM = coef f icient f or bending momentCV = coeff icient f or shear

w = unit weight o f liquid

H = height of the liquid

Ri = inner radius of the wall.

The values of the coef f icients are tabulated in IS:3370 1967, Part 4, f or various values o f H2/Dt, at

dif f erent depths o f the liquid. D and t represent the inner diameter and the thickness of the wall,

respectively. The typical variations of CT and CM with depth, f or two sets of boundary conditions are

illust rated. The roo f can be made of a dome supported at the edges o n the cylindrical wall. Else, the ro of

can be a f lat slab suppo rted o n columns along with the edges. IS:3370 1967, Part 4, provides coef f icientsf or the analysis of the floo r and roof slabs.


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Design steps

Calculate diameter and height o f water tank

Assumed suitable thickness

Calculate designed constants

Calculate hoop tensio n, maximum bending moment by using IS 1370 part IV.

Check the assume thickness with given permissible values o f tensile st resses o f concrete in direct

tension f or the given grade of concrete.

Actual circumf erential prestress i.e. actual direct compressive stress (f c)

Provide circumf erential steel , Provide vertical steel

Check f or ultimate co llapse and cracking Non prestressing steel /untensioned steel

Design base slab

Draw detail

Comparison of R.C.C. water tank and Prestrssed water tank

The tanks to be consider having some common data such as the tanks are having same capacity, same

diameter, same height, same grade of concrete i. e. (M40) & (M50), the thickness o f tank f loo r sho uld be

taken either 150mm or equal to the wall thickness(if greater than 150mm) f or RCC water tank and minimum

thickness f or priestesses concrete water tank is 120mm.We consider tank capacity f or bo th the cases (i.e.RCC & Priestesses) reimaging from 1000 m3 to 9000 m3. f or both the grade o f concrete i.e. (M40 & M50).

The result so obtained as given in following table3

Schedule For RCC Water Tanks & Prestressed Concrete Water Tanks Estimate Details


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CAPACITY GRADE OFCONCRETE

COST OF P.C. WATERTANK

% OFCOST

COST OF R.C. C.WATERTANK

m3 Rs Rs

1000 M40 2056116 11.47 1844521

M50 2101677 9.43 1920546

2000 M40 2777828 -20.33 3486806

M50 2845004 -21.69 3633328

3000 M40 3811166 -24.87 5072773

M50 3897242 -26.22 5282492

4000 M40 5268049 -21.06 6673611

M50 5404513 -22.50 6973950

5000 M40 6696401 -18.14 8180441

M50 6852226 -20.01 8567341

6000 M40 7901981 -22.35 10177486

M50 8143194 -23.45 10637885

7000 M40 8988532 -19.34 11144740

M50 9255833 -21.42 11778868

8000 M40 1169380 -15.02 13761735

M50 1199296 -16.63 14385223

9000 M40 1277439 -16.45 15290975

M50 1309013 -18.05 15975177

NOTE: (Negative value of % saving indicates t hat prestressed concrete tank is econo mical than RCC water

tank and vice--versa)


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Figure 1: Variation Of Cost With Capacity Of Water Tank & Grade Of Concrete

Figure 2 Variation Of Cost For Both Type Of Water Tank With Same Grade Of Concrete(M40)

Figure 3 Variation Of Cost For Both Type Of Water Tank With Same Grade Of Concrete(M50)


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Figure 4 Variation o f % of saving for given capacity with given grade of concrete(M40)

Figure 5 Variation o f % of saving for given capacity with given grade of concrete(M50)

The aim of this paper is to compare the cost of R.C.C. water tanks resting over f irm ground with the cost

of Prest ressed concrete water tanks. In India at least , mos t o f the small & medium sized water tanks are

constructed in RCC. Senior engineers and those in the know maintain that prest ressed concrete water

tanks are not worth t rying f or smaller capacities. Besides cost , ot her reason may be that prestressed

concrete const ruction involves skilled labor & supervision. Furthermore, prest ress ing is a closely guarded

technology in this country & info rmation is not available that easily.

There is no clear-cut def inition of Medium Size. The thumb rule passed on in the f ield f rom one

generation o f engineers to the next, f ixes a value around 10 lac liters. Theref ore, this study encompasses

tanks f rom 10 lac liter capacity to 90 lac liter capacity. A couple of cases o f both varieties were designed

manually. Design & Est imation programs were developed in MS EXCEL f or both RCC & Prest ressedconcrete. The programs were f inalized af ter a number of trial runs & corrections.


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Results obtained are compiled in f igures numbered 1 to 5 & Table numbered 3. D/H ratio f or all the tanks is

maintained at 4 based on the recommendations of the Preload Engineering Company of the US, a world

leader in the f ield of prest ressed concrete water tanks. It should be noted that an increase in tank wall

thickness results in decreased f lexural steel in case o f RCC. However, in case of prest ressed concrete, an

increased thickness leads to a greater prestressing f orce & consequently more prest ressing steel. Thus,

increased thickness leads to increased cost in case o f prestressed concrete.

Table3 presents the to tal cost of each tank along with the % dif f erence. + means cost lier prestressing &

- means cheaper prestressing. As the tank capacity increases, the cost of tank increases. But the conceptof economics o f scale holds goo d i.e. the cost of a tank of 20 lac liter capacity is less t han double the

cost o f a tank o f 10 lac liter capacity. Similarly, the cos t o f a tank of 90 lac liter capacity is less t han 9 times

the cos t o f a tank of 10 lac liter capacity. It can be clearly established that the grade of concrete hardly

makes any dif f erence in the cost ing. Because o f its nature, the water tank design is never an impending or

boundary line design. The f actor o f saf ety is high & the actual stresses are much lower than the

permissible ones. An increased permissible stress f or a higher grade of concrete hardly makes any

diff erence to the f inal outcome.

Finally, a study of the same Table3 conf irms t hat the RCC tank is cheaper only for 10 lac liter capacity. For

higher capacities, prestress concrete tank is always cheaper by @ (20 +/- 5) %. This is because the

thickness of an RCC tank increases many-f olds f or higher capacities. Thickness in f act seems to be an

important criterion even for prestressed tanks. An increased thickness leads to an increased prestressing

f orce. More s teel is required to generate this higher prestressing f orce resulting in higher cost .

CONCLUSION

RCC tanks are cheaper only for smaller capacities up to 10-12 lac liters. For bigger tanks, Prestressing is

the superior choice resulting in a saving of @ 20%.


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REFERENCES:

1 Tanetal (1966) Minimum Cos t Design Of Reinforced Concrete Cylindrical Water Tanks Based On The

British Code For Water Tanks, Using A Direct Search Method And The (SUMT). European Journal Of

Scientif ic Research ISSN 1450 - 216XVol.49No.4(2011),pp.510-520.

2 Thakkar and Sridhar Rao (1974)Cost Optimization Of Cylindrical Composite Type Prestesses Concrete

Pipes Based On The Indian Code Journal of Structural Engineering 131: 6.

3 Al-Badri (2005) Cost Optimization Of Reinforced Concrete Circular Grain Silo Based On ACI Code

(2002)American Concrete Institute Structural Journal, May- June 2006.

4 Hassan Jasim Mohammed Econo mical Design Of Water Tanks European Journal Of Scientif ic Research

ISSN 1450 -216XVol.49No.4(2011),pp.510-520.

5 Abdul-Aziz & A. Rashed Rational Design Of Priestesses And Reinforced Concrete Tanks Dept Of Civil &

Environmental Engineering. University Of Alberta, Edmontan, Alberta Canada T6g-267.Euro journals

Publishing. Inc.2011

6 Chetan Kumar Gautam Compariso n Of Circular RC And PSC Underground Shelters The Indian Concrete

Journal April 2006.

7 Precon Designing Of Circular Prestressed Concrete Tanks To T he Industry Standards Of The AWWA And

ACI journal of pries tesses concrete institute vo l.12,apr. 1967

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We at engineeringcivil.com are thankful to MS. SNEHAL R. METKAR for submitting this useful information to

us. We hope this will be of great help to all those who are looking forward for Economics of R.C.C. Water tank

Resting over Firm Ground vis-a-vis Pre-stressed Concrete Water Tank Resting over Firm Ground.

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