My Final year Project

PLANNING, ANALYSIS, DESIGN AND ESTIMATION OF NATURAL COOLING TOWER

A PROJECT REPORT Submitted by S.RAMANAN (08CER080) G.SWATHY (08CER103) J.ARUNACHALAM (08CEL118)

In partial fulfillment for the award of the degree Of BACHELOR OF ENGINEERING IN CIVIL ENGINEERING

SCHOOL OF BUILDING AND MECHANICAL SCIENCES KONGU ENGINEERING COLLEGE, PERUNDURAI-638 052 (An Autonomous institution affiliated to Anna University of Technology, Coimbatore)

ANNA UNIVERSITY: COIMBATORE-641 047 OCTOBER-2011

ANNA UNIVERSITY: COIMBATORE-641 047 1

BONAFIDE CERTIFICATE Certified that this project report on “PLANNING, ANALYSIS, DESIGN

AND ESTIMATION OF NATURAL COOLING TOWER” is a bonafide work of S.RAMANAN (08CER080) G.SWATHY (08CER103) J.ARUNACHALAM (08CEL118)

Who carried out the project work under my supervision

SIGNATURE

SIGNATURE

Prof.S.KRISHNAMOORTHY, M.E.,

Mrs.S,SUCHITHRA. M.E.,

Head of the Department

Assistant Professor

School of Building and Mechanical Sciences Department of Civil Engineering

School of Building and Mechanical Sciences Department of Civil Engineering

Kongu Engineering College

Kongu Engineering College

Perundurai, Erode-638 052

Perundurai, Erode-638 052

Submitted for the University Examination held on ______________

Internal Examiner

External Examiner

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ACKNOWLEDGEMENT

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ACKNOWLEDGEMENT First and foremost we thank the almighty, the greatest architect of the universe for giving us such a speculate years. We wish to express our heartfelt thanks to our beloved Correspondent Thiru.R.K.VISHWANATHAN, B.A., and other philanthropic trust members for having provided us with the entire necessary infrastructure to undertake this project. We are greatly indebted to express our deep sense of gratitude to our principal, Prof.S.KUPPUSWAMI, B.E., Msc (Engg). Dr.Ing (France) for his valuable advice and encouragement during the project. We are grateful to thank our beloved Dean of School of Building and Mechanical Sciences Dr.K.KRISHNAMOORTHY, M.E., Ph.D., FIE, FIV for his infallible inspiration and guidance. We take immense pleasure to express our heartfelt thanks to our beloved Head of the Department Prof.S.KRISHNAMOORTHI, M.E., for his encouragement and kind co-operation. This work would not have been materialized without the great guidance given to us by our guide Mrs.S.SUCHITHRA, M.E., Ph.D who had been a constant source of ideas and inspiration with encouragement. We heartily thank our Project Co-ordinator for their valuable guidance. Last but not least, we thank our PARENTS and BELOVED FRIENDS for their moral support.

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ABSTRACT

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ABSTRACT Our project involves the Planning, Analysis and Design of an Natural Cooling Tower. The entire design includes slab design, beam design, column design, and footing design. Calculations are made manually and using software packages. The various structural elements are designed using IS 456:2000. The concrete mix used for slabs, beams and footings are of M25 and the steel used for all members are high yield strength deformed bars of grade Fe415. Each and every part is designed by considering the safety point of view and economically. This project deals with a simple and effective Natural Cooling Tower design which is designed similar to Pyramid structure with slight modification to increase its efficiency instead of normal Sand-Clock like structure which involves tough calculations and tedious rafter column designs. This is a new concept in Cooling Tower design which strike in our mind when we were gone to Industrial Visit at Mettur Themal Power Station. 2

The total area of Cooling tower is 662 m with three compartments which are used for cooling the hot water supplied to it. The first bottom compartment consists of filler material above which steel grill is placed to hold the distribution pipe with sprinklers which carries the hot water and sprinkles it. The Second compartment which is above the first compartment will have a big slab with opening at the centre which converges and reduces the area of vapour reaching the top. Obviously, the vapour starts to condense more and reaches the collecting chamber at the bottom. And the third, topmost compartment consists of empty space which has a large opening at the centre than at the Second compartment which allows the remaining vapour that comes out after condensing at second compartment to reach the top widely.

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The objectives of this project are Main objective:  To create a new design in cooling tower construction instead of conventional structures which are tedious to built  To prepare an economical and effective design using Pyramid like structure  To make use of atmospheric air for natural cooling instead of electric fan  To prepare simple design instead of complicated design (to avoid designing of Rafter Column as like in normal cooling tower)

Supplementary Objective:  To draw a plan of Natural Cooling Tower showing the reinforcement details of slabs, columns, beams and footings are done AutoCAD 2009.  To analyze the structure elements using STADD. Pro V8i.

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CONTENTS

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CONTENTS CHAPTER NO

TITLE

PAGE NO

ABSTRACT 1.

INTRODUCTION

2.

LITERATURE REVIEW

3.

PLAN

4.

MANUAL DESIGN

4.1 SLAB DESIGN 4.2 BEAM DESIGN 4.3 COLUMN DESIGN 5.

SOFTWARE DESIGN 5.1 COOLING TOWER

6.

REINFORCEMENT DETAILS 6.1 SLAB DETAILS 6.2 BEAM DETAILS 6.3 COLUMN DETAILS

7.

ESTIMATION OF COOLING TOWER

8.

CONCLUSION

9.

REFERENCE

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LIST OF FIGURES

S.NO

TITLE

1.

3D VIEW OF COOLING TOWER

2.

REINFORCEMENT DETAIL OF BEAMS,COLUMNS

3.

REINFORCEMENT DETAIL OF SLAB,FOOTING

PAGE NO

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LIST OF SYMBOLS B

–

D

– Overall depth of beam or slab or diameter of column, dimensions under considerations

Breadth of beam or shorter dimension of a rectangular column

W – d

Total Dead load

W – s

Total live load

D

–

Effective depth of beam or slab or footing

f

–

Characteristic compressive strength of concrete

–

Characteristic strength of steel

–

Effective span of beam or slab or effective length of column

–

Shorter dimension of the slab

–

Longer dimension of the slab

M

–

Bending Moment

A

–

Area of tension reinforcement

–

Moment of resistance of a section without compression

f l

l l

ck

y

eff

x y

st

M

u

reinforcement X

X

x

y

–

Shorter span co-efficient

–

Longer span co-efficient

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–

Moments in strip per unit width of shorter span

–

Moments in strip per unit width of longer span

–

Permissible stress in concrete in bending compression

–

Spacing of the stirrup legs or bent-up bar with in a distance

P u

–

Axial compressive force

M

–

Bending moment at a cross section

P c

–

Percentage of compression reinforcement

P t

–

Percentage of tension reinforcement

M M

 S

x y

cbc v

u

Pw –

Axial compression on wall assumed to act at centre of wall

Av –

Area of vertical steel

λ

Non dimensional parameters

–

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INTRODUCTION

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INTRODUCTION

In this present era, the technology in advanced construction has developed to a very large extent. Some parts of constructions are still in improving stage which includes Cooling Tower construction. Some researches are going on to increase the efficiency of Cooling Tower by modifying its structure and design. Ordinary Sand-Clock shaped Cooling Towers are very tedious to design and calculate. In this chapter, we are going to deal with planning, analysis and design of Natural Cooling Tower in brief. The design is done by two methods. The first one is manual analysis and the other one is STADD Pro analysis. In manual design, all the Slabs, Beams and Columns are taken. The design philosophy and procedures are taken as per the Indian standards. This whole structure design is done by limit state design.

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LITERATURE REVIEW 15

LITERATURE REVIEW COOLING TOWER Cooling Towers are evaporative coolers used for cooling water or other working medium to near the ambient wet-bulb air temperature. Cooling towers use evaporation of water to reject heat from processes such as cooling the circulating water used in oil refineries and power plants, building cooling, or chemical reactions, for example.

TYPES OF COOLING TOWERS I.

MECHANICAL DRAFT COOLING TOWERS

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Mechanical Draft Cooling tower has following characteristics,  Large fans to force air through circulated water  Water falls over fill surfaces: maximum heat transfer  Cooling rates depend on many parameters  Large range of capacities  Can be grouped, e.g. 8-cell tower DISADVANTAGES OF MECHANCIAL DRAFT COOLING TOWER  Towers are very flexible  High vibration values during startup.  Complex gearbox (1800/120 RPM)  Starting cell 2 can shut down cell 1  Reversing fans in cold climates  Water build up in blades  Speeds are slow and based on diameter  Distance to control room  Corrosion from bad pH 17

II.

NATURAL DRAFT COOLING TOWER

A natural draft cooling tower is a means to remove waste heat from a system and release it into the atmosphere.Typically used at oil refineries, chemical plants and power plants to remove heat absorbed from circulating cool water systems.A common shape is the hyperboloid (See Fig. 1) Cooling towers have been around for over 100 years. However, in their early for were only about 20 meters high. Today, some can reach over 200 meters.“As recently as 20 years ago, cooling towers were more the exception than the rule in the industry because of their severely high operating cost and the large amount of capital required for construction. But with today's need for water conservation and minimal environmental impact. industry is turning more and more to recycling water.”(GC3) . It has following advantages,  Hot air moves through tower  Fresh cool air is drawn into the tower from bottom  No fan required  Concrete tower 2.50 Hence it is considered as oneway slab DEPTH REQUIRED FOR STIFFNESS: Span/(depth x modification factor) = 20 Assume pt =1.2% 10600/(depth x 0.95) =20 Depth = 560mm D’ =600mm Effective span = 10.6+0.6 =11.2 m LOADS: Load calculation= 1 x 0.6 x 25 = 75KN/m Self weight of slab = 1 x 4 = 4KN/m Total= 19KN/m Ultimate load = 28.5 KN/m BENDING MOMENT: Mu = Wul2/8 = [28.5 x(11.2) 2]/8 = 446.88 KN/m Vu = Wul/2 = (28.5x 11.2)/2

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=159.6N/mm2 LIMITING MOMENT: Mu lim = 0.138 fck bd2 = 0.138 x 25 x 1000 x (560)2 = 1081KN-m Mulim >Mu Hence it is Under reinforced section MAIN STEEL REINFORCEMENT AND SPACING: Mu=0.87 fy Ast d[1-(Ast fy/bd fck)] Astreq=6662.40mm2 Spacing =110mm Provide 32dia @110mm c/c (Ast)pro = (1000 x ast)/spacing = 7307.63 mm2 (pt) req= 100 x Ast req bd 1.1>1.2 Hence it is safe DISTRIBUTION REINFORCEMENT: Ast min = 0.12 x bd = (0.12/100) bd = 720mm2 Spacing =270mm Provide 16mm dia @ 270mmc/c CHECK FOR DEFLECTION:

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fs =0.58 x fy x Ast req/ Ast pro = (0.58 x 415 x 6717)/7307.6 =221N/mm2 pst (assumed )=1.2% M.F=0.95 Depth d= span/(20 x M.F) = 10600/(20 x 1.2) =555mm< d (assumed) Hence it is safe CHECK FOR SHEAR: Vuc =(Tc x bd ) x k fck = 25 KN/mm2 p st = 100 x Ast pro/ bd = 0.53% Tc = 0.61 N/mm2 Vuc = 0.61 x 1000 x 560 x 0.95 = 324.52 KN Vuc>Vu Hence it is safe

BEAM DESIGN DATA: fck = 25 N/mm2 fy = 415 N/mm2 27

Working load =15 KN/m Ultimate load = 19 KN/m Width of support = 0.6m CROSS SECTIONAL DIMENSION: Span/depth = 20 10.2/20 = depth Depth= 510 mm D= 550mm Effective span

= clear span+ effective depth = 10+0.55 = 10.55mm

Center to center support = (10 + 0.6) = 10.6m length = 10.55m

(which ever is lesser)

LOAD CALCULATION: Self weight of beam dead load = 0.6 x 0.6 x 25 = 9 KN /m Live load = 5KN/m Total load = 14 KN/m Ultimate load = 21KN/m

ULTIMATE MOMENT AND SHEAR FORCE: Mu = (Wu x L²) = ( 21x 10.55²)

= 292.16KN-m

Vu = (Wu x L) = (21x10.55)

=110.78KN

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LIMITING MOMENT OF RESISTANCE: Mu limit = 0.138 x fck x b x d² = 0.138 x 25 x 600 x 550² =745.2KN/m Mu < Mu (limit) since the sec is under reinforcement Hence the section as singly reinforcement. DESIGN OF TENSION REINFORCEMENT: Mu=0.87 x 415 x Ast x 550 x (1-((Ast x fy)/ (b x d x fck))) 745.2x 10^6=0.87 x 415 x Ast x 550 x (1-((Ast x 415)/(600x 550 x 25)) Ast=1403.12mm² (Ast) pro= (1000 x ast)/(spacing) , Assume 12mm dia bars, Provide 12mm dia bars @240mm c/c Also provide 2no.s of hanger bar of 12mm dia bars CHECK FOR SHEAR REINFORCEMENT: Tv =Vu/bd = 110.78x10^3/600*550 = 0.184 N/mm^2 Pt =(100*Ast)/bd =100*1404/600*550 =0.25% Refer table 19 IS 456:2000 ,Pg no;73 Tc =0.36 N/mm^2 Tv