Vetical Dam Hoist Mechanism
-
Upload
krishnanselva -
Category
Documents
-
view
191 -
download
19
description
Transcript of Vetical Dam Hoist Mechanism
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
13
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
19
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