CHAPTER – 1

INTRODUCTION

1.1 KERALA ELECTRICAL AND ALLIED ENGINEERING

COMPANY LIMITED (KEL)

The Kerala Electrical and allied engineering company Limited, popularly known

as KEL was established in 1964 in the state of Kerala, India and fully owned by the

state government. As a company engaged in multiple activities, they have broadened

their manufacturing base strategically to reach wider domestic and overseas market.

With man power base of 1000 which include more than 150 qualified and well trained

engineers, they are one of the biggest public sector companies in the state. The company

has four manufacturing units located in various districts of the state.

1.2 LITERATURE REVIEW

In this conceptual project, we are designing a vertical dam gate with greater life

period than the ordinary dam gates. In this project, a study has been made on the

existing vertical dam gates.

In the existing system, the skin plate and associated parts of the dam gate are

made with mild steel only. Then the surface is thoroughly cleaned. After that, zinc rich

epoxy primer (85%zinc) is coated over it. And then a coating of coal tar epoxy primer is

applied. The life of the dam gate is about 60 years. These gates are affected by corrosion

due to continuous contact with water and require greater maintenance.

We then thought of improving life of the dam gate. We suggested that by

replacing mild steel skin plate with stainless steel skin plate, we can improve the life of

the dam gate from 60 years to 80 years, since stainless steel has more life period than

mild steel. Mr.K.H.Shaji (deputy manager-planning, production and subcontract)

suggested that in order to reduce cost it is better to weld a thin stainless steel plate to a

thick mild steel plate. Mrs.Snehalatha T.V (manager- planning and subcontract)

approved our suggestion by stating that the concept is applicable in “wet and

inaccessible” condition.

1

1.3 DAM

Almost every water resources project has a reservoir or diversion work for the

control of floods or to store water for irrigation or power generation, domestic or

industrial water supply. A spillway with control mechanism is almost invariably

provided for release of waters during excess flood inflows. Releases of water may also be

carried out by control devices provided in conduits in the body of the dam and tunnels.

In order to achieve flow control, a gate or a shutter is provided in which a leaf or a

closure member is placed across the waterway from an external position to control the

flow of water. Control of flow in closed pipes such as penstocks conveying water for

hydropower is also done by valves, which are different from gates in the sense that they

come together with the driving equipment, whereas gates require a separate drive or

hoisting equipment.

Right selection of gates and their hoisting arrangement is very important to

ensure safety of the structure and effective control. A designer has to plan a gate and its

hoisting arrangement together. Separate planning of gates or hoists, sometimes results

in unsatisfactory installation. Though the choice for the gates and hoists depends on

several factors, primarily safety, ease in operation as well as maintenance and economy

are the governing requirements in the same order. It is essential for the water resources

engineer to be aware of the different factors, which would largely affect the choice of

gates and hoists and would help in selection of the same.

The past thirty-first to forty years has been a period of unprecedented water in

our country. Besides a large number of small irrigation and hydro-electric scheme,

more than 3000 dams have been constructed. All structures or projects harnessing

water needs gates for controlling the flow as such large number of gates of different

types had to be designed and manufactured. The design of gates consequently

undergone considerable development, since the use of wooden (gates) ‘needles’ or

‘curries’ used in ancient time and has enable us to fabricate gate for high heads and

situations.

2

Whatever may be the type of dam, it is absolutely necessary to provide a safe

passage for the flood water, so as to avoid the danger of the dam being overtopped. The

part of dam which discharges the flood flow to the downstream side is called as spillway.

The spillway is an important part of dam complex and is located either as a part of main

dam or separately at suitable place near to the dam.

1.4 GATE

The crest control for a spillway may be achieved either through automatic

devices or through manually operated devices known as gate. In view of various

considerations such as operational maintenance, manufacturing etc. gate can be

classified into three types. The Bureau of Indian Standards code IS 13623: 1993 Criteria

for choice of gates and hoists provides the basic classification of gates.

Flap gate

Radial gate

Vertical dam gate

1.4.1 Flap Gates

The flap gate are located of the basin side of the caisson, which would lessen the

downward component of the water load carried which may cause sliding and

overturning under differential heads. To overcome this, flap gates have to be kept

particular angle to vertical to downward components of water forces on the gates.

1.4.2 Radial Gates

The radial gates are structurally more efficient than flap gates. The radial gates

could be appropriate cost for shallow waters, in deeper part of the estuary. The hinge

pins will be located below the normal tidal making the maintenance more difficult. It

can be operated under differential heads. They are easily accessible for minor

maintenance and painting but for major maintenance, a floating crane or a barrage is

needed. The operating costs are less. They can be again reduced by counter weights.

3

1.4.3 Vertical Dam Gates

Vertical dam gates can be operated to suite overall barrage requirements

including flood control. The gates can be maintenance above high water and if

necessary, they can be removed and replaced through the top of the caisson by floating

crane. A vertical dam gate mounted in venture passage would give a relatively large

discharge capacity. The discharge coefficient is about 1.5 for vertical dam gate and is

shown in Figure 1.1.

The wheels are mounted on the end girders. The bottom of gate should be so

shaped that satisfactory performance and freedom from harmful vibrations are

attained under all conditions of operation apart from minimizing down pull. A sectional

view with a typical arrangement of various components of gate is shown in Figure 1.2.

Figure 1.1 Arrangement of Vertical Dam Gate with Hoist

According to IS 4622:1992 fixed wheel gates can be classified on the basic of water heat

above sill level as follows.

High head gate: Gate which operates under a head of 30m and above, but less

than 30m.

Medium head gate: Gate which operates under a head of 15m and above, but less

than 30m.

Low head gate: Gate which operates under a head less than 15m.

4

Figure 1.2 Vertical Dam Gate with Fixed Wheel-Sectional View

Some of the important features are:

It can operate at differential heads.

It can be easily inspected.

They can be easily accessible for minor maintenance and painting.

They are not easily accessible for major maintenance; a floating crane is needed.

Operating cost is less. They can be further reduced by counter weights.

Vertical dam gates are not affected by wave damage, since they are protected by

wave breakers and closure panel.

Some of the important terminologies associated with gates are given below, which would

help one to understand the operation of gates more closely.

Skin plate

Vertical stiffeners and horizontal girders

Wheels and wheel tracks

Seals and accessories

Guide and guide shoes

Track base

5

Seals seat, seal base and sill beam

Anchorages

1.4.3.1 Skin Plate

A membrane which transfers the water load on a gate to the other components.

1.4.3.2 Horizontal and Vertical Stiffeners

Horizontal girders are the main structural members of a gate, spanning horizontally to

transfer the water pressure from the skin plate and vertical stiffeners (if any) to the end

girders or end arms of the gate. Vertical girders (also called vertical stiffeners) are the

structural members spanning vertically across horizontal girders to support the skin

plate.

1.4.3.3 Wheels and Wheel Tracks

Wheels provided on the sides of a gate to restrict its lateral and/or transverse

movements. A structural member on which the wheels of a gate move.

1.4.3.4 Seals and Accessories

A seal is a device for preventing the leakage of water around the periphery of a gate. A

bottom seal is one that is provided at the bottom of the gate leaf. Side seals are those

that are fixed to the vertical ends of gate leaf. A top seal is one that is provided at the

top of a gate leaf or gate frame.

1.4.3.5 Guide and Guide Shoes

That portion of a gate frame which restricts the movement of a gate in the direction

normal to the water thrust. A device mounted on a gate to restrict its movement in a

direction normal to the water thrust.

1.4.3.6 Track Base

A structural member on which the wheels of a gate move.

6

1.4.3.7 Seal Seat, Base and Sill Beam

This is the top of an embedded structural member on which a gate rests when in closed

position.

1.4.3.8 Anchorages

An embedded structural member, transferring load from gate to its surrounding

structure.

1.5 Material Used in Fabrication of Gates

Steel gates

Wooden gates

Reinforced concrete gates

Aluminium gates

Fabric (plastic) gates/Rubber gate

Cast iron gates.

1.6 HOISTS FOR VERTICAL DAM GATE

The mechanical arrangements used for operating the gates are called Hoists. The

Bureau of Indian Standards code IS 6938 – 1989 “Design of rope drum and chain hoists

for hydraulic gates – code of practice” lays down the guiding principles for design of

rope drum and chain hoists. The general principle of a rope drum and chain hoist for

vertical dam gates is shown in Figure 1.3.

Figure 1.3 Rope Drum Hoist Arrangements for Vertical Dam Gate

7

1.7 DIFFERENT EFFECTS ON VERTICAL DAM GATE

1.7.1 Earthquake Effect

Where the project lies in a seismic zone earthquake forces shall be considered in

accordance with IS11893:1984, and the gate designed accordingly

The allowable stress as given in table-5 shall be increased by 33.5 percent in case

of earthquake conditions subject to an upper limit of 85 percent of the yield point. In

case of nuts and bolts increase in stress shall not be more than 25 percent of allowable

stress. The permissible value of stresses in welded connections shall be the same as

permitted for parent material.

1.7.2 Wave Effect

For every wide big reservoir, the effect of wave height of wave height due to

storms, act. In causing increase loading on the gate, shell also be considered.

Increased stress in various parts of the gate, as described in the earthquake

forces shall be allowed for the wave effect.

The earthquake forces and the wave effect shell not be considered to act together

while computing the increased stress in the gate.

1.7.3 Ice Loading

Ice impact and pressure: Provided local conditions do not impose other values, ice

impact and ice pressure shall be taken in to account in such a way that the water

pressure triangle shall be replaced as given below:

In water with ice thickness greater than 300mm, by an even surface pressure of

30000 N/m² up to 3 depth, and

In water with ice thickness up to 300mm, by an even surface of 2000 N/m² up to 2

depth.

1.7.4 MWL Condition

In case the gate is to be checked for MWL condition, the allowable stress shall be

increase by 33.5 percent of the values specified in annex subject to the upper limit of

yield point.

8

1.8 OPERATION AND MAINTENANCE OF VERTICAL DAM

GATES

The proper operation and maintenance of vertical gates and hoists is important

for satisfactory operation of the project. The proper operation of the gate is important

for the safety of the works of the projects. For safe and systematic operation and

maintenance of the gates and operation equipment, it is very important that a

comprehensive operation and maintenance manual is prepared for the vertical dam

gate installation on the project.

The operation manual for the gate installation should contain operating

instruction, necessary precaution and sequence of operation for working any equipment

and accessories on the work. It should also include instruction for adjustment, which is

required to be carried out during operation of any equipment.

Operating personnel should be properly trained and experienced. It is desirable

that graphs and charts are maintained for various characteristics or individual

equipment. Experience on operation and difficulties, if any encountered should be

recorded in the log book of each equipment so as to be available for studying the

behavior of various structures and equipments.

1.8.1 Inspection and Maintenance

Detailed instruction for inspection and normal maintenance and repairs for gate

installations should be given in the operation and maintenance manual. However for

carrying out special repairs for any equipment, reference to manufacturers drawing

and manuals is necessary for deciding the mode of special repairs and maintenance. In

order that the inspection and maintenance experiences are complied in the form of

history of any installation so as to be useful for future designs or better investigations of

any failure improper to unusual operation of any equipment, all such observations can

be recorded in the equipment history registers maintained for this purpose.

9

The operation and maintenance personnel shall be familiar with general design

and a construction features of the works and equipments so that they can carry out

proper maintenance. Safety instructions and specific precautions for any particular

operation should be given in inspection, operation and maintenance manual. Such

precautions and instructions shall be followed prior to, during and after the completion

of the inspection and maintenance operation.

Periodic inspection and maintenance schedules for various equipments shall be

included in the manual. Operation and maintenance also includes charts in respect of

particulars including manufacture of all brought-out items, lubrication schedule and

painting schedule. The operation and maintenance manual should also contain details of

rubber seals or items which require periodic replacement and requirement of

lubricants, spares and tools which should be kept in stock at any time.

10

CHAPTER – 2

DESIGN OF VERTICAL DAM GATE

2.1 DESIGN DATA

Clear width of opening L =400 cm

Clear height of opening Hc =500 cm

Full supply level FSL =588.24 cm

Maximum water level MWL =589.2 cm

Sill level SL =578 m

Roller distance from edge RE =27.5 cm

Side seal distance from edge SE =5 cm

Sill to C.I of top seal Ht =Hc+5=500+5 =505 cm

Spacing of stiffener a =32 cm

Total hydrostatic head (WH) = FSL-SL

=588.24-578

=10.24 m

2.2 DESIGN STANDARDS

(i) I.S 4622 – Fixed wheel gates structural design-Recommendations.

(ii) I.S 800 – Code of practice for general construction in steel.

(iii) I.S 456 – Code of practice for plain and reinforced concrete.

2.2.1 Material Standards

(i) I.S 2062 – Hot rolled low, medium and high tensile structural steel

(ii) I.S 1570 (part 2)–Schedule of wrought steels(carbon steels-unalloyed)

(iii) I.S 1570(part 5)–Schedule of wrought steels(stainless and heat resisting

steels)

(iv) I.S 1030–Carbon steel castings for general engineering purposes-

specification

2.3 MATERIAL SPECIFICATIONS

Skin plate, Stiffeners, Girders etc. - IS 2062

11

Wheels - IS 1030, Gr 280-520

Wheels pin -Stainless steel 12Cr12, IS 1570

Wheels track -Stainless steel 20Cr13, IS 1570

2.3.1 The permissible conditions shall be applicable to wet and inaccessible

condition

Yield Stress σyp =250×10.2 =2.55×103 kg/cm2

Direct/Bending stress σb =0.4× σyp =0.4×2.55×103=1.02×103 kg/cm2

Shear stress τ =0.3×2.55×103 =765 kg/cm2

Combined stress σ c =0.5 σyp

σc = 0.5 2.55 x 103= 1.27 103 kg/cm2

Bending stress on concrete σ con = 50kg/cm2

2.4 DESIGN FOR SKIN PLATE

Total hydrostatic head WH = FSL-SL

= 588.24-578.0 =10.24 m

c/c tracks L1 = L+2RE

= 400 +2 27.5= 455 cm

c/c side seals L2 = L+2SE

= 400+2 5 = 410 cm

Height of the bottom unit H1 = 220 cm

Height of the top unit H2 = Ht-H1

= 505-220 = 285 cm

Total load on gate Pt = L2 Ht/(100 100) (WH-Ht/(2 100))

= 410 505/10000(10.24-505/(2 100))

=159.74 t

Total load on bottom unit p1 = L2 H1/10000(WH-(H1/200))

= 410 220/10000(10.24-(220/200))

= 82.44 Ton

Thickness of skin plate S1 = 1cm

With corrosion allowance =1.5mm

Effective thickness S = S1-0.15 = 0.85 cm

Spacing of girders l1 = 0.15 m

l2 = 0.9 m

l3 = 0.9 m

12

l4 = H1/100-(l1+l2+l3)

= 220/100-(0.15+0.9+0.9)

= 0.25 m

Pressures (in m of water)

P1 = WH = 10.24m

P2 = P1-l1 =10.24-0.15 =10.09 m

P3 = P2-0.5l2 =10.09-0.5 0.9 = 9.64 m

P4 = P3-0.59l2 = 9.64-0.5 0.9= 9.19 m

P5 = P4-0.5l3 = 9.19-0.5 0.9= 8.74 m

P6 = P5-0.5l3 =8.74-0.5 0.9 = 8.29 m

P7 = P6-l4 = 8.29-0.25 = 8.04 m

Figure 2.1 Diagram for Skin Plate, Stiffener Along With Panels

2.4.1 Panel A-B

a1= a = 32 cm

b1= l2 100 = 0.90 100 =90 cm

For b/a = 2, for σ 3x1, k1=50 (from table 2, I.S 4622)

σ 3x1 = k1/100 P3 (a1 2/s 2) 1/10

= 50/100 9.64 32 2/0.85 2 1/10

= 683.14 kg/cm 2

σ 3y1 = 0.3 σ 3x1

= 0.3 683.14 =204.94kg/cm 2

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Figure 2.2 Diagram for Panel A-B

2.4.2 Panel B-C

a2= a; b2 = l3 100 = 90 cm

b 2/a 2 = 2.81

For b/a = 2, k 2 = 50

σ 3x2 = (k2/100) P5 (a2 2/s 2) (1/10)

= 50/100 8.74 (32 2/0.85 2) (1/10)

= 619.36 kg/cm 2

σ 3y2 = 0.3 σ 3x2

= 0.3 619.36 = 185.81kg/cm 2

Figure 2.3 Diagram for Panel B-C

2.5 DESIGN FOR STIFFENER

2.5.1 Panel A-B

Ra = P4 (l2/2) 100 +0.5(P2-P4)/10 (l2/100) 2/3

= 9.19 (0.9/20) 100+0.5(10.09-9.19)/10 0.9 100 0.667

14

= 44.06 kg/cm

Rb = 0.5 l2 100 (P2-P4)/10+(P4/10) l2 100 – Ra

= 0.5 0.9 100 ((10.09-9.19)/10)+(9.19/10) 0.9 100 – 44.06

= 42.7 kg/cm

For maximum bending moment, equating shear to zero:

0.5 (P2-P4)/(10 l2 100) X 2+(P4/10) X = Rb

0.5 (10.09-9.19)/(10 0.9 100) X2+9.19/10 X = 42.7

0.0005X2 +0.919X – 42.7 = 0

X = -0.919 +√ (0.9192+4 0.0005x42.7)/2 0.0005 = 43.35cm

Maximum bending moment at X

M1 = Rb X–P4/10 X X/2

M1 = 976.05 kg.cm

Bending moment in each stiffener

bms1 = M1 a

= 976.05 32 = 3.12 104 kg.cm

Figure 2.4 Bending Moment Diagram for Stiffener Panel A-B

2.6 EFFECTIVE WIDTH OF SKIN PLATE (We)

L2= 0.91m, a = 32 cm

L2 100/(0.5 a) = 0.91 100/0.5 32 = 5.63

From IS 4622;

We = 2 (a/2) Vi = 2 (32/2) 0.7 = 22.4 cm

15

2.7 DESIGN OF BENDING STRESS FOR STIFFENER

Section Area Y AyY1,Y2,

Y

YAy-2 Isdf Total

22.4 0.85

6.7 0.8

25 2

19.04

5.36

6

0.425

4.2

7.95

8.092

22.512

47.7

Y1=2.58

Y2=5.77

2.155

1.57

5.37

88.422

13.212

173.0124

0.83

20.058

0.32

295.35

30.4 78.304

Y1 = ∑AY/∑A

= 78.304/30.4 = 2.58 cm

I self = bd3/12

Y2 = (0.85+6.7+0.8)-2.58 = 5.77 cm

Zs11 = 295.35/2.58 = 114.477 cm3

Zs12 = 295.35/5.77 = 51.1872 cm3

Bending stress, bs1 = Mbs1/Z s11

= 3.12 104/114.47 = 272.5438 kg/cm2

bs2 = Mbs2/Zs12

= 3.12 10/51.1872 = 609.527 kg/cm2

Figure 2.5 Conventional Diagram for Stiffener

2.7.1 Panel B-C

Rb1 = P6 l3/20 100+0.5(P4-P6)/10 l2 100 2/3

= 8.29 0.9/20 100+0.5 (9.19 – 8.29)/10 0.9 100 2/3

= 40.01 kg/cm

R c = 0.5 l3 100 (P4 – P6)/10 + P6/10 l3 100 –Rb1

= 0.5 0.9 100 (9.19–8.29)/10+8.29/10 0.9 100– 40.01

= 38.65 kg/cm

R c = 0.5 (P4-P6)/(10 l3 100) X12+(P6/10) X1

16

38.65 = 0.45/900 X12 + 0.829X1

0 = 0.0005X12+0.829X1–38.65

X1 = -0.829+√ (0.8292 + 4 0.0005 38.65)/2 0.0005 = 45.38 cm

M2 = Rc X1–P6/10 X12/2–0.5(P4-P6)/10 l3 100 X1

3 0.5 1/3

= 38.65 45.38-8.29/10 45.382/2–0.5(9.19-8.29)/(10 0.9 100)

45.383 0.5 1/3

= 892.55 kg cm

2.8 BENDING MOMENT OF STIFFENER

bms2 = M2 a = 892.73 3.2 = 2.86 104 kg cm

2.8.1 Bending stress

fs21 = bms2/Zs1

= 2.86 10/114.477 = 249.83 kg/cm2

fs22 = bms2 /Zs2

= 2.86 10/51.187 = 558.73 kg/cm2 <σ b

Figure 2.6 Bending Moment Diagram for Stiffener Panel B-C

2.9 DESIGN FOR HORIZONTAL GIRDER

WA = P1 l1 10 + 0.5 l1 (P1-P2)10 + Ra

= 10.09 0.15 10 + 0.5 0.15 0.15 10 + 44.06

= 59.3 kg/cm

WB = ( Rb+ Rb1) = 44.7+40.01

= 84.71 kg/cm

WC = P7 l4 10+0.5(P6-P7)l4 10+Rc

= 8.04 0.25 10+0.5(8.29 – 8.04) 0.25 10+Rc

= 59.06 kg/cm

RA = WA 0.5 l2 = 59.3 0.5 410 = 1.22 10 4 kg

17

RB = WB 0.5 l2 = 84.71 0.5 410 = 1.7 10 4 kg

RC = WC 0.5 l2 = 59.06 0.5 410 = 1.21 10 4 kg

Figure 2.7 Diagram for Horizontal Girder

2.9.1 Bending moment for Horizontal Girder

bmgb = RB(L1/2 – L2/4) = 1.7 10 4(455/2 – 410/4)

= 2.12 10 6 kgcm

2.10 EFFECTIVE WIDTH OF SKIN PLATE

L = 4550 mm B = 450 L/B =10.11

Vi = 0.95 (From IS 4622 graph)

a = 2 0.95 450

= 85.5 cm

Sectional properties:

a = 85.5 cm, T1= 0.85 cm, b1 = 38 cm, a2 = 25 cm, T2= 2 cm, t = 0.8 cm

Section Area Y Ay Y1,Y2,Y Y Ay-2 Isdf Total

85 0.8

38 0.8

25 2

72.625

30.40

50

0.425

19.85

39.85

30.886

603.44

1992.5

Y1 =17.16

Y2 =23.69

Y3 =16.31

17.1

3.84

23.54

20365.54

448.26

22706.58

4.376 104

3.66 1034.7 104

153.075 2626.826

Y1 = ∑Ay/∑A

= 2626.826/153.075 = 17.16 cm

Y2 = (T1 + b1 + T2)–Y1

= 0.85+38+ 2–17.16 = 23.69 cm

Y3 = Y1-T1

= 17.16 – 0.85 = 16.31 cm

Iself = 4.4 104

Zgb1 = Igb/ygb1

= 4.7 10 4/17.16 = 2.7 103 cm

18

Zgb2 = Igb/ygb2

= 4.7 /23.69 = 2 103 cm

Zgb3 = Igb/ygb3

= 47 /16.31 = 2.9 103 cm

2.11 BENDING STRESS IN GIRDER

fgb1 = bmgb/Zgb1

= 2.12 106/2.7 103 = 785.19 kg/cm2

fgb2 = bmgb/Zgb2

= 2.12 106/2 103 < 1.02 103kg/cm2

= 1 103 kg/cm2

fgb3 = bmgb/Zgb3

= 2.12 106/2.9 103 = 731.03 kg/cm2

2.11.1Shear stress in the web

Depth of the web at the end d1= b1 = 38 cm

Thickness of the web at the end t1e = t1 = 0.8 cm

Sgb1 = RB/d1e t1e = 1.7 104/38 0.8 = 557.75 kg/cm2 < 765

Modulus of elasticityE = 2047000 kg/cm2

δ = 5 WB L14/384 E Igb = 0.45 < L1/800 = 0.57

L1/δ = 1.01 10 3

Figure 2.8 Conventional Diagram for Horizontal Girder

2.11.2Girder A

bmga = RA (L1/2 – L2/4) = 1.52 106 kg cm

Effective width of skin plate

ө = л/6, b2 = 10 cm, t2 = 1 cm, a3 =v1g (l1+0.5 l2) 100,

a3=57, T3=s, b3=(b1-b2)/cos (θ), b3=32.33, t3=t2,

x1=b3 cos(θ), x1=28, a4=18, T4=2.0

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yGA1 = [a3 T3 T3/2+b2 t2 (T3+b2/2)+b3 t3 (T3+b2+b3/2 cos(θ))

+a4 T4 (T3+b2+x1+T4/2)] /(a3 T3+b2 t2+b3 t3+a4 T4)

yGA1 = 18.28 cm

yGA2 = T3+b2+x1+T4-yGA1 yGA2 = 22.57 cm

yGA3 = yGA1-T3 yGA3 =17.43 cm

IGA1 =a3 T3 (yGA1-T3/2)2+b2 t2(yGA1-b2/2-T3)2+b3 t3(T2+b2+b3/ 2 cos(θ)-yGA1)2

IGA2 = a4 T4 (T3+b2+b3 cos(θ)+T4/2-yGA1)2+t3 b33/l2 cos(θ)2

IGA = IGA1+IGA2 IGA= 3.74 104 cm4 IGA1= 1.84 104 cm4

Zga1 = IGA/yGA1 Zga1= 2.04 103 IGA2= 1.89 104 cm3

Zga2 = IGA/yGA2 Zga2= 1.65 103 cm3

Zga3 = IGA/yGA3 Zga3= 2.14 103 cm3

fga1 =bmga/Zga1 fga1= 745.65 kg/cm2

fga2 = bmga/Zga2 fga2= 920.95 kg/cm2

fga3 = bmga/Zga3 fga3= 710.97 kg/cm2

Shear stress τ = RA/(d1 e t2) τ = 319.93 kg/cm2

Figure 2.9 Conventional Diagram for Horizontal Girder A

2.11.3Girder C

Bending moment in girder bmgc = RC (L1/2 –L2/2)

= 1.21 10 (4550/2 – 4100/2)

= 1.51 106 kg cm

Effective width of skin plate (a1) = L1/0.5 l3 100=10.11 Vi = 0.95

a1 = Vi (0.5 0.9 + 0.25)100 =66.5 cm

Y1 = 2062.06/122.92 = 16.77 cm

Y2 = (0.85+38+2)–16.77 = 24.08 cm

Y3 = 16.77– 0.85 = 15.92 cm

y[ = 16.77 – 0.425 = 16.345 cm

20

Section Area y Ay Y1,Y2,Y Y Ay-2 Isdf Total

66.5 0.85

38 0.8

18 2

56.523

0.4

36

0.425

19.85

39.85

24.02

603.44

1434.6

Y1=16.77

Y2=24.08

Y3=15.92

16.345

4.23

23.93

15099.83

543.94

20615.22

3.4 104

3.66 1043.82 104

122.92 2062.06

Ay-2 = 56.52 16.345 = 15099.83 cm2

Zgc1 = Igc/Ygc1 = 3.82 104/16.77 = 2.88 103 cm3

Zgc2 = Igc/Ygc2 = 3.82 104 / 24.08 = 1.59 103 cm3

Zgc3 = 2.9 103 cm3

Bending stresses in girders

fgc1 = bmgc/Zgc1 = 1.51 106/2.28 103 =662.28 kg/cm2

fgc2 = 953.3 kg/cm2

fgc3 = 630.58 kg/cm2

Figure 2.10 Conventional Diagram for Horizontal Girder C

Shear stress in web

Sgc = Rc/d1e t1 = 1.21 104/38 0.8 = 398.02 kg/cm2

Combined stress in the skin plate at X on the outer face of skin plate

σ 11 = -σ 3x1+fgb1 = -683.14+727.8 = 44.66 kg/cm2

σ 31 = -σ 3y1+fs11 = -204.99+272.2 = 67.26 kg/cm2

σ c1 = √ (σ 112 + σ 31

2 – σ 11 σ 31)

= √(44.44+67.26–(44.66-67.26) = 59.24 kg/cm2

On the inner face of skin plate

σ 12 = σ 3x1+fgb3 = 1.37 103 kg/cm2

σ 32 = σ 3y1+fs11 = 204.94+272.2 = 477.14 kg/cm2

= √( σ 122+ σ 32

2 –σ 12 σ 32 )

21

= √(1.37 103) 2+477.142– (1.37 103 477.14)

= 1.2 103 kg/cm2

Figure 2.11 Conventional Diagram for Combined Stresses in the Skin Plate

Total load on bottom unit

P = L2 /100 H1/100 (P1+P2)/2

= 410/100 220/100 (10.24+8.04)/2 = 82.44 t

Check

PC = 2 (RA+RB+RC)/1000

= 2 (1.22 104+1.7 104+1.21 104)/1000 = 82.6 t

Location of centre of pressure

hr = H1/3 2 P7+P1/(P7+P1)

= 220/3 2 8.04+10.24/(8.04+10.24) = 105.59 cm

Figure 2.12 Diagram for Load on Bottom Unit

Distance of the bottom wheel from the bottom of the gate

y1 = 33.5 cm

Distance between the wheels

y2 = 145 cm

Wheel load W1 = P/2 (y1+y2-hr)/145

22

= 82.44/2 33.5+145–105.59 = 20.73 t

W2 = P/2-W1 = 82.44/2-20.73 = 20.49 t

2.12 DESIGN OF END GIRDER

Bending moment at W1

M3 = RA(Y1-l1 100) =1.22 104(33.5-0.15 100) =2.25 105kg-cm

Bending moment at B

M4 = W1 1000[(l1+l2)100-Y1]-RA l2 100

=20.73 1000[(0.15+0.9)100-33.5]-1.22 104 0.9 100

=1482195-1098000 =3.84 105kg-cm

Figure 2.13 Conventional Diagram for End Girder

Effective width of skin plate

23

li = 0.6 Y2, b =a/2, li/b=5.44, Vi=0.85

Effective width a5 = 3.25+13+0.85 16

Sectional properties

Section Area Y Ay Y1,Y2,Y Y Ay-2 Iself Total

29.85 0.85

40 1.2

40 1.2

25.374

8

48

0.425

20.85

20.85

10.78

1000.8

1000.8

Y1=16.58

Y2=24.2716.155

3.42

6621.16

561.43

1.52

0.64 1042.16 104

121.37 2012.38

Yeg1 = 2012.38/121.37 =16.58 cm

Yeg2 = T5+b3-Yeg1 = 0.85+40-16.58 = 24.27 cm

Zeg1 = Ieg/Yeg1 = 2.16 104/16.58 =1.3 103cm3

Zeg2 = Ieg/Yeg2 = 2.16 104/24.27 = 889.98 cm3

feg1 = M3/Zeg1 = 2.25 105/1.3 103 =173.07 kg/cm2

feg2 = M3/Zeg2 = 2.25 105/889.98 = 252.81 kg/cm2

Figure 2.14 Conventional Diagram for Horizontal Girder Section at B

2.13 DESIGN OF WHEEL

Maximum wheel load W1 = 20.73 t

Material of the wheel cast steel Gr 280-520, IS1030

Ut = 5.3 103 kg/cm2

Modulus of elasticity E = 2047000 kg/cm2

Wheel diameter Dw = 30 cm

Length Lw = 7 cm

24

Actual contact stress σc = 0.418 √((W1 1000 E)/(0.5 Dw Lw))

= 0.418 √(20.73 1000 2047000)/(0.5 30 7)

= 8.4 103 kg/cm2

2.14 SELECTION OF BEARING

Provide a spherical roller bearing no.21316cc

Db = 8, Db = 17, B = 3.9, Static capacity = 335 k

2.15 DESIGN OF WHEEL PIN

Maximum BM in pin

lp = 14+2.4 = 16.4 B = 3.9

bmp = 0.5 W1 1000(lp/2-B/4)

= 0.5 20.73 1000(16.4/2-3.9/4) = 7.49 104kg-cm

Zp = πdb3/32 = π 83/32 = 50.27 cm3

Bending stress, fbsp = bmp/Zp

= 7.49 104/50.27 = 1.49 103

Material stainless steel 30Cr13

BHN in the annealed condition, BHN = 220

uts = 490 BHN/14.19

= 490 220/14.19 uts = 7.6 103kg/cm2

Permissible stress, σa1 = 0.2uts = 1.52 103kg/cm2

Figure 2.15 Diagram for Wheel Pin

Shear stress

Minimum diameter of pin at one end d1 = 6.5 cm

Area Ap = 3.14 d12/4 = 3.14 6.52/4 = 33.17 cm2

= 0.5 W2 1000/Ap = 0.5 20.49 1000/33.17

= 308.95 kg/cm2

25

2.16 DESIGN OF TOP UNIT

Height of top unit H2 = Ht-H1 = 285 cm

Spacing of girders l1 = 0.25 m, l2 = 1.2 m, l3 = 1.2 m,

l4 = H2/100-(l1+l2+l3) = 0.2 m

2.16.1Design of Skin Plate

Thickness s =10 mm, Pressure (in m of water)

P1 = WH-(H1/100) = 10.24-(220/100) = 8.04 m

P2 = P1-l1 = 8.04-0.25 = 7.79 m

P3 = P2-0.5l2 = 7.79-0.5 1.2 = 7.19 m

P4 = P3-0.5l3 = 7.19-0.5 1.2 = 6.59 m

P5 = P4-0.5l3 = 6.59-0.5 1.2 = 5.99 m

P6 = P5-0.5l3 = 5.99-0.5 1.2 = 5.39 m

P7 = P6-l4 = 5.39-0.2 = 5.19 m

a = 32 cm, b = 120 cm, b/a = 120/32 = 3.75

for b/a = 2.86,for σ 3x, k = 509 from table2, IS4622)

Panel A-B

σ 3x1 = k/100 P3 a2/s2 1/10 =50/100 7.19 322/102 1/10

=3 68.13 kg/cm2

σ 3y1 = 0.3 σ 3x1 = 0.3 368.13

= 110.44 kg/cm2

Panel B-C

σ 3x2 = k/100 P5 a2/s2 1/10 = 50/100 5.99 322/12 1/10

= 306.69 kg/cm2

σ 3y2 = 0.3 σ 3x2 = 0.3 306.69

= 92.01 kg/cm2

2.17 DESIGN OF STIFFENER

Panel A-B

Ra = P4 l2/20 100+0.5(P2-P4)/10 l2 100 2/3

= 6.59 1.2/20 100+0.5(7.79-6.59)/10 1.2 100 2/3

= 43.98 kg/cm

26

Rb = 0.5l2 100 (P2-P4)/10+P4/10 l2 100-Ra

= 0.5 1.2 100 (7.79-6.59)/10+6.59/10 1.2 100-43.98)

=42.3 kg/cm

For maximum bending moment, equating shear to zero

0.5 (P2-P4)/(10 l2 100)X2+P4/10 X = Rb

0.5 (7.79-6.59)/(10 1.2 100)X2+ 6.59/10 X = 41.94

0.0005X2+0.659X = 41.94

X = (-b±√b2-4ac)/2a

= (-0.659±√(0.6592+4 0.0005 41.94))/(2 0.0005)

= 60.83cm

M1 = Rbx-P4/10 X/2-(P2-P4)/(10 l2 100) X3 0.5 1/3

= 1.29 103 kg/cm

Ms1 = M1 a = 4.14 104 kg/cm

Figure 2.16 Bending Moment Diagram for Stiffener

Effective width of skin plate, (We) l2 = 1.2 m, a = 32 cm

From IS 4622, Vi = 0.83

l2 100/(0.5 a) = 1.2 100/(0.5 32) = 7.5

We = 2 a/2 7.5 = 2 32/2 7.5 = 26.56 cm

a0 = 26.56 cm, T0 = s = 10 mm, b0 = 6.7 cm, t0 = 0.8 cm, a1 = 7.5 cm,

T1= 0.8 cm

Sectional properties

Section Area Y Ay Y1,Y2 Y AY2 Iself

Itotal

27

26.56 1 26.56 0.5 13.28 2.25 1.75 81.34 105.2

6.7 0.8 5.36 4.35 23.316 6.25 1.9 19.35 20.05 330.36

0.8 7.5 6 8.1 48.6 5.6 188.16 205.335

Y1 = ∑Ay/∑A = 85.196/37.92 = 2.25 cm

Y2 = (T0+b0+T1)-Y1 = 1+6.7+0.8-2.25 = 6.25 cm

Zs1 =I total/Y1 = 330.36/2.25 =146.83cm3

Zs2 = Itotal/Y2 = 330.36/6.25 = 52.86 cm3

Bending stresses

fs11 = Ms1/Zs1 = 4.14 104/146.83 = 281.958 kg/cm2

fs12 = Ms1/Zs2 = 4.14 104/52.86 = 783.20 kg/cm2

Panel B-C

Rb = P6 l3/20 100+0.5 P4-P6/10 l3 10 2/3

= 5.39 1.2/20 10+0.5 (6.59 – 5.9)/10 1.2 100 2/3 = 37.14 kg/cm

Rc = 0.5 l3 100 (P4-P6)/10+P6/10 l3 100 –Rb

= 0.5 1.2 100 6.59–5.39/100+5.39/10 1.2 100–37.14 = 34.74 kg/cm

For maximum bending moment

0.5 P4-P6/10 l3 100 X12+P6/10 X1 = Rc

0.5 (6.59–5.39)/10 1.2 100 X12+5.39/10 X1 = 34.74

0.0005 X12+0.539X1–34.74 = 0

X = -b ± √b2-4ac/2a

= -0.53± √0.5392+ 4 0.0005x34.74/2 0.0005 = 61cm.

M2 = RcX1–P6/10X12/2–0.5 (P4-P6)/(10 l3 100) 13 0.5 1/3

= 1.1 103 kg/cm

Ms2 = M2a = 3.51 104 kg/cm

fs21 = M2a/Zs11 = 238.79 kg/cm2

fs22 = M2a/Zs12 = 664.63 kg/cm2 <1020 kg/cm2

28

Figure 2.17Conventional Diagram for Stiffener

2.18 HORIZONTAL GIRDER

WA = [P2 l1 10+0.5 l1 (P1–P2) 10+Ra]

= [79 0.25 10+ 0.5 0.25 (8.04–7.79) 10 +44.34] = 64.13 kg/cm

WB = (Rb+Rb1) = 79.08 kg/cm

WC = [P7 l4 10+0.5 (P6–P7) l4 10]+Rc = 45.32 kg/cm

RA = WA 0.5 L2 = 1.32 104 kg

RB = WB 0.5 L2 = 1.62 104 kg

RC = WC 0.5 L2 = 9.29 103 kg

Bending moment

bmgb = RB(L1/2–L 2/4) = 2.03 106 kgcm

Bending stress

fgB1 = bmgb/ZgB1 = 695.86 kg/cm2

fgB2 = bmgb/ZgB2 = 960.62 kg/cm2

fgB3 = bmgb/ZgB3 = 661.39 kg/cm2

Shear stress in web

Depth of web at the end of d1e = 35

Thickness of web at the end t1e = 0.8

SgB1 = RB/d1e t1e = 1.62 104/35 0.8 = 578.57 < 765 kg/cm2

29

Combined stress in the skin plate at X

On the other face of skin plate

σ11 = -σ 3x1+fgB1 = -368.13+695.86 = 327.73 kg/cm2

σ 31 = -σ 3y1+fs11 = -110.44+281.67 = 171.23 kg/cm2

σ c1 = √ σ112+σ31

2–σ11 σ31

= √ 327.732+171.232– 327.73 171.23 = 283.92 kg/cm2

On the inner face of skin plate

σ12 = σ 3x1+fgB3 = 368.13+661.39 = 1.03 103kg/cm2

σ32 = σ 3x1+fg11 = 110.4+281.67 = 392.11 kg/cm2

σ12 = √ σ122+σ32

2– σ12 σ32

= √(1.03 103)2+392.112–1.03 103 392.11 = 899.98 kg/cm2

Girder C (provide same section for girder A also)

bmgc= RC (L1/2–L2/4) = 9.29 103 (455/2–410/2)

= 1.16 106 kgcm

Bending stress in grider

fgc1 = bmgc/Zgc1 = 1.16 106/2.28 103 = 508.7 kg/cm2

fgc2 = bmgc/Zgc2 = 1.16 106/1.59 103 = 729.559 kg/cm2

fgc3 = bmgc/Zgc3 = 1.16 106/2.4 103 = 48.33 kg/cm2

Total load on top unit P = L2/100 H2/100 P1+P7/2

= 410/100 285/100 8.04+5.9/2 = 77.3 t

Check PC = 2 RA+RB+RC/1000

= 2 1.31 104+1.62 104+9.29 103/1000 = 77.2 t

Location of centre of pressure

Hr = H2/3 (2 P7+P1)/(P7+P1)

= 285/3 (2 5.19+8.04)/(5.19+8.04) = 132.27cm

Distance bottom wheel from bottom of gate y1 = 43.4 cm

Distance between the wheel y2 = 171.6 cm

Wheel load W1 = P/2 y1+y2– hr/y2

=77.2/2 43.4+171.6– 132.27/171.6

= 18.63 t

W2 = P/2-W1= 77.2/2–18.63 = 20.01 t

30

Figure 2.18 Diagram for Horizontal Girder

Hoist capacity and check for self closing intake gate

(i) Wheel friction (ii) Total load on a gate P

Average head on gate Hav = WH –Ht/200 WH = 10.24 m

Hav = 10.24– 505/200 = 10.24 – 2.525

= 7.71 m.

P = Ht/100 L2/100 Hav

= 505/100 410/100 7.71 P =159.64 t

Mean radius of bearing r = 0.25 (db + Db) 10

= 0.25 (8 + 17) 10r = 62.5mm.

F1 = P/0.5 DW 10 (0.015 62.5 + 1)

= 159.64/0.5 30 10 F1 = 2.06 t

Seal friction F2

Length of side seal Ht = 505 cm

Length of top seal L2 = 410 cm

Head on top seal Ht = WH – Ht/100 = 10.24 – 505/100

= 5.19 cm.

Effective leaded with of seal Ws = 0.04 m

Frictional co-efficient µ = 0.2 [Teflon cladded seal]

F2 = [2 Ht/100 Ws hav + ht Ws L2/100] µ

= [2 500/100 0.04 7.71 + 5.19 0.04 410/100] 0.2

= 0.7932 t

Friction in seal due to pre-compression.

For 3 mm pre-compression, force per meter length = 1 kg/cm

Total force on scale Fs = (2Ht + L2)

= (2 505 + 410)

= 1.42 103 t

31

Friction due to pre-compressions F3 = µ fs/1000

= 0.2 1.42 103/1000

= 0.28 t

Uplift on top seal

Total projection of top seal from the face of skin plate xt = 1.0 + 4.2 = 5.2 cm.

Total uplift on top seal F4 = xt L2 (ht/10)/1000

= 5.2 410 (5.19/10)/1000

= 1.11 t

Minimum download force required at 250 kg/m

Fo = 0.25 L1/100

= 0.25 455/100 = 1.14 t

Minimum weight of gate required Wgm = F1 + F2 + F3 + F4 + Fo

= 2.06+0.7932+0.28+1.11+1.14

= 5.30 t

Weight of bottom unit Wg1 = 2.578 t

Weight of top unit Wg2 = 2.634 t

Wheel assembly Wg3 = 8 x 0.34 = 0.274 t

Weight of gate Wg = Wg1+Wg2+Wg3 = 5.48 t

Weight of gate Wg = 6.0 t

Down pull gate F5 = 3 t

Hoist capacity Hc1 = 1.2(wg + F1 + F2 + F3 + F5)

=1.2(6+2.03+0.7932+0.28+1.11+1.14)

Hc1 = 14.57 t

Provide 15 t capacity hydraulic hoist

32

CONCLUSION

This conceptual project titled “DESIGN OF VERTICAL DAM GATE AND

HOIST MECHANISM” provided an insight on improving the life of dam gate from 60

years to 80 years. This is an economical way of producing a vertical dam gate with

greater life. This project also provided a chance to study about the various components

of the vertical dam gate such as skin plate, stiffener, girder, wheel etc., and also the

pressure acting on various points on the skin plate. Also the various design calculations

like reaction forces, bending moments, bending stresses, shear stresses and combined

stresses were calculated and found out that the calculated values come under the safe

limit.

Design values :

Direct/bending stress σb = 1.02 × 103 kg/cm2

Shear stress τ = 765 kg/cm2

Combined stress σc = 1.27 × 103 kg/cm2

Calculated values :

Direct/bending stress σh = 683.14 kg/cm2

Shear stress of girder τ = 557.75 kg/cm2

Combined stress σc = 1.2 × 103 kg/cm2

33

REFERENCES

For books

1. R.K.Bansal , editor. Fluid mechanics. New Delhi: Lakshmi Publication;2007.

2. S.Senthil, editor. Strength of materials. New Delhi: Lakshmi Publication;

Seventh Edition 2009.

3. I.S 4622 – Fixed wheel gates structural design-Recommendations. Bureau of

Indian Standards.

Website

4. http://en.wikipedia.org/wiki/Floodgate .

5. http://www.fantes.com/stainless-steel.html .  

6. http://www.fanagalo.co.za/tech/tech_grade_304.html .

7. http://www.azom.com/Details.asp?ArticleID=965 .

34

PHOTOGRAPHY

Vertical Dam Gate in KEL

35

36

Vertical Dam Gate

37