DESIGN ASPECT OF VARIOUS TYPES OF GATAES - PAPER BY ER. A.P. PANDEY C.D.O. GANDHINAGAR, Gujarat

1. ONE DAY WORKSHOP ON DAM’S GATES
ORGANISED BY
NARMADA, WATER RESOURCES, WATER SUPPLY
& KALPSAR DEPARTMENT
GANDHINAGAR
SUPPORTED BY
WALMI - ANANAD

2. SUB:-DESIGN ASPECT OF VARIOUS
TYPES OF GATAES
PAPER BY
ER. A.P. PANDEY
C.D.O. GANDHINAGAR

4. Being vital components of dams, gates
are installed on spillway to store water and
create reservoir behind them.
They regulate the release of water for
various purposes for which they are
planned.
The spillway gates regulate and control
the flood discharge., Outlet gates control the
release water for irrigation, penstock gates
release water for power generation.

5. Basic requirements to be satisfy by the
gates
are as under:
(1) Water tightness
(2) Can be operated by hoist at specified speed.
(3) Alternative operation device in case of power
operated gate.
(4) Regulating gate should be held in any partials
operation position to pass required discharge
without cavitations and undue vibration.

7. • The unobstructed operation of the flood
gates of any water project is of utmost
importance.
• The choice of the type of gate and its
operating mechanism is critical for that
reason
• For low head flood gates of dams, which are
usually quite wide, the conventional choice
includes Vertical Lift, Radial, Automatic or
Needle type gates.

8. • The operation And maintenance of each
type is unique and each type presents
certain advantages and disadvantages.
• The primary considerations for the
selection of the gate type include gate size
requirement, expected flows, efficiency of
discharge and initial cost.

10. There are so many classifications for designating
the types of gates. Out of that following three most
commonly used.
TYPES OF GATES
(1) On the bases of design head:
(2) On the bases of location and purpose
(3) On the basis of their operation and shape.

11. (1) On the bases of design head:
• High head – above 30m
• Medium head‐ between 15m to 30m
• Low head – less than 15m

12. 2 On the bases of location and purpose
1.Crest gates :
» Spillway crest gates and
» Barrage crest gates
2. Outlet gates :
» By pass outlet gates
» H.R. Gates
» Penstock intake gates
» Sluice gates
Construction sluices
Scouring sluices
Under sluice

13. 3 On the basis of their operation and shape.
– Radial gate/ Taintor gate
– Vertical lift gates
– Automatically lifting gates
– counter wt. operated
– Float operated
– Counter wt. and flood operated
– Flap shutters
– Automatic tilting gates/ Godbole gates

14. Most common type of gate used for hydraulic
structure i.e. vertical lift gates.
1. Stoney gates
2. Cater piller gates
3. Fixed wheel gates
4. Sliding gates
Vertical lift gates provide with wheels on sides
to reduce the friction are known as fixed wheel
gates and without wheel is known as sliding gate.

37. AUTOMATIC TILTING GATE
(GODBOLE GATE)

43. • In spillway with high Tail water, Vertical Lift Gates are
generally superior to Radial Gates . Trunnion assembly
under water is not desirable because of the possibility
of debris impinging upon it and causing damage .
• Bigger gates require bigger wheels or rollers which in
turn necessiate bigger gate groove. Bigger groove
create turbulent flow by the side of the piers and also
there is a tendency for the floating debris or trees to
lodge in these gate grooves. This will prevent smooth
operation of gates during flood.
• Higher gates are also necessiate in increased height of
piers.

44. • The radial shape provides efficient transfer of
hydrostatic loads through the trunnion.
• A lower hoist capacity is required.
• Radial gates have a relatively fast operating speed
and can be operated efficiently.
• Side seals are used, so gate slots are not required.
This reduces problems associated with cavitations,
debris collection, and buildup of ice.
• Radial gate geometry provides favorable hydraulic
discharge characteristics.

45. Disadvantages
[ 1]To accommodate location of the trunnion, the
pier and foundation will likely be longer in the
downstream .Larger piers increase cost due to
more required concrete and will usually result
in a less favorable seismic resistance due to
greater height and mass.
(2) End frame members may encroach on water
passage. This is more critical with inclined end
frames.
(3) Long strut arms are often necessary where
flood levels are high to allow the open gate to
clear the water surface profile.

49. Vertical Gates Involves design of
• Skin plate
• Vertical And Horizontal Stiffeners And Main
girder
• Wheels
• Seals And Accessories
• Guide Rollers
• Wheel track And Track base
• Sill beam
• anchorages

50. SKIN PLATE
T‐VERTICALS
STIFFNERS
BRACING

52. Skin plate and Stiffeners
• Skin plate and Stiffeners shall be designed
together in composite manner
• It shall be designed in bending across the
stiffeners or Horizontal girders as
applicable. To take care of corrosion the
actual thickness of skin plate shall be
provided at least 1.5 mm. more than the
theoretical thickness computed.
• The stiffeners may be of a built up section or
of standard rolled section.

53. Horizontal/Vertical Stiffeners and Main Girder
• The Horizontal and Vertical Stiffeners Shall be
designed as simply supported or continuous
beam depending upon framing adopted for
gate.
• The spacing between main horizontal girders
shall be preferably such that all the girders
carry almost equal load.
• Maximum deflection of gate under normal
condition of loading shall be limited to 1/800
of the span.

54. T‐ VERTICAL
BRACING

55. Wheels And Wheel Track
• The gate wheels shall be suitable to
withstand the stresses developed due to
hydrostatics loads, which they will carry.

56. GUIDE ROLLER TRACK
VERTICAL GROOVE

57. Wheel Track and Track base
• The wheel track shall provide a true and
smooth machined surface for the wheels to
roll and transmit the loads through the
wheels to track base.

58. END VERTICAL
ROLER PIN
MAIN ROLLER

60. Seals And Accessories
• Seal shall be fixed by means of seal clamps
or S.S.bolts so as to ensure a positive water
pressure between the seal and gate and to
bear tightly on the seal seat to prevent
leakage.

61. GUIDE ROLLER TRACK
SIDE SEAL TRACK
VERTICAL
GROOVE
EQUILIZER PLATE
END LIFTING BRACKET
VERTICAL STIFFNER
PLATE

62. Guide Rollers
• Gate Guide Rollers shall be provided on the
sides of the gates to limit the lateral motion
of the gate to not more than 6 mm. in either
direction.
• A minimum of two guide rollers should be
provided on each side of the gate to resist
the transverse and lateral movement of the
gate at same time to prevent the gate for
jamming.

63. Sill Beam
• The minimum Width of Seal seat shall be 80
mm. excluding the required chamfer.
• The Minimum Thickness of the S.s. plate for
low head gates be 6 mm. and for medium
and high head gate is 8 mm.
• The sill beam may be provided with the
corrosion resistant steel flats welded or
screwed with corrosion resistant steel
sheets. The surface of sill beam may be
machined smooth.

64. SILL BEAM

65. Anchorages/ anchor Plates
• Anchorages shall be provided in first stage
concrete, with suitable block out openings
to hold the embedded parts of second stage
concrete. The minimum size of Anchor Bolts
shall not be less than 16 mm. and anchor
plate thickness shall not be less than 8 mm.

70. 1. CREST LEVEL
2. F.R.L.
3. H.F.L.
4. T.W.L.
5. TYPES OF SPILLWAY

71. SIZE OF GATE SHALL BE SPECIFED AS THE CLEAR WIDTH
OF OPENING & THE VERTICAL HEIGHT ABOVE
CREST/SILL OF GATE UPTO THE F.R.L. EXCLUDING FREE
BOARD.

72. • NORMALLY, RADIAL GATE HAS AN UPSTREAM SKIN PLATE BENT TO AN
ARC WITH CONVEX SURFACE OF ARC IN U/S SIDE.
• THE CENTRE OF ARC IS AT THE CENTRE OF TRUNNION PIN, ABOUT
WHICH THE GATE ROTATES.
• THE SKIN PLATE IS SUPPORTED BY SUITABLY SPACED STIFFENERS
EITHER HORINZONTAL OR VERTICAL . IF VERTICAL STIFFENERS ARE
USED, THESE ARE SUPPORTED BY SUITABLY SPACED HORINZONTAL
GIRDERS WHICH ARE SUPPORTED BY RADIAL ARMS.
• THE ARMS TRANSMIT WATER LOAD TO THE TRUNNION/ANCHOR
GIRDER.
• SUITABLE SEALS ARE PROVIDED ALONG CURVED ENDS OF GATE &
ALONG BOTTOM.
• GUIDE ROLLERS ARE ALSO PROVIDED TO LIMIT SWAY OF GATE DURING
RAISING/LOWERING.
• TOTAL WATER THRUSTS ON GATE ARE TRANSMITTED THROUGH
TRUNNION WHICH ARE FASTENED WITH ANCHOR GIRDER.
• ANCHOR GIRDER TRANSFERS ALL LOADS TO PIER THROGH HORIZONTAL
AND VERTICAL ANCHORAGES.

74. :
1. GATE SHALL BE WATER TIGHT.
2. MAX. PERMISSIBLE LEAKAGE SHOULD NOT BE
MORE THAN “5 LTRS./MIN./M. LENGTH OF SEAL”.
3. GATE SHALL BE CAPABLE OF BEING
RAISED/LOWERED BY HOIST AT SPECIFIED SPEED.
4. POWER OPERATED GATES SHALL NORMALLY BE
CAPABLE OF OPERATION BY ALTERNATIVE MEANS
IN CASE OF POWER SUPPLY FAILURE.
5. GATE SHALL BE CAPABLE OF BEING HELD IN
POSITION WITHIN RANGE OF TRAVEL TO PASS
REQUIRED DISCHARGE WITHOUT CAVITATION &
UNDUE VIBRATION.

75. (A) FIXING THE PARAMETERS LIKE
(1) LOCATION OF SILL
(2) LOCATION OF TRUNNION
(3) TOP OF GATE
(4) RADIUS OF GATE
(5) LOCATION OF HOIST

76. THE SILL OF GATE SHALL PREFERRABLY BE
LOCATED SLIGHTLY D/S OF CREST TO AVOID
CAVITATION OF D/S GLACIS .
IN GENERAL PRACTICE , WE PROVIDE 0.25
TO 0.35 m BELOW CREST TOWARDS D/S.

77. IT SHOULD BE AT LEAST 1.5 M. ABOVE WATER
PROFILE (UNDER H.F. L. CONDITION.)
RESULTANT HYD. THRUST IN GATE POSITION
FOR F.R.L. CONDITION LIES AS CLOSE TO
HORI. AS POSSIBLE. (1/3 HEIGHT OF GATE)
NOT ALLOWED IN SUBMERGED CONDITION.
T.W.L. SHALL BE BELOW 1.0 M.
NONE OF ANY PARTS OF CIVIL STRUCTURES
INTERFERE WHILE RAISING/LOWERING
GATE.

78. FOR EFFECTS OF WAVE, FREE BOARD SHALL
BE PROVIDED ABOVE F.R.L.
NORMALLY, TI WILL BE 0.3 M.
TOP OF GATE = F.R.L.+0.3 M.

79. RADIUS OF GATE IS THE DISTANCE FROM
CENTRE OF TRUNNION PIN TO INSIDE OF
SKIN PLATE.
IT SHOULD BE 1.0 TO 1.25 OF HEAD OF
WATER. i.e. H TO 1.25 H.
LARGE RADIUS SHALL INCREASE PIER
DIMENSION.

80. HOIST SHALL BE SO LOCKATED THAT, AS
FAR AS POSSIBLE, HOISTING FORCE IS
APPLIED TO GATE AT LARGEST POSSIBLE
RADIUS & HOISTING ANGLE DOES NOT
CHANGE MUCH DURING TRAVEL OF GATE.

81. (1) SKIN PLATE & STIFFENERS
(2) HORINZONTAL GIRDER
(3) ARMS
(4) TRUNNION ASSEMBLY
(a) TRUNNION HUB
(b) TRUNNION PIN
(C) TRUNNION BUSH
(d) TRUNNION BRACKET
(5) LOAD CARRYING ANCHORAGES—
ANCHOR GIRDER

82. COMPONENT RECO. MATERIALS I. S. NO.
Skin Plate, Stiffeners, Structural Steel 808, 2062, 8500
Horizontal Girder, Arms,
Anchor Girder, Anchor
rods
Guide Rollers Cast Steel 1030
Structural Steel 2062
Forged Steel 1875
Trunion hub & Brackets Cast Steel 1030
Structural Steel 2062
Pin Structural Steel 2062
Corrosion resisting 6603
Steel
Bushing Bronze/ Self lubricating 305,306,318
bushing
Seal Steel Stainless Steel 6911
Seal base & Seal beam Structural Steel 2062,8500

83. Type of Stresses Nature Allowable values
Bending stresses Tension 1260 kg/cm2
kg/cm2
Compression 1260
kg/cm2
Shear 945
Combined bending stress 1400 kg/cm2
(Biaxial)
Stress in weld Bearing 1020 kg/cm2
kg/cm2
Shear 785
kg/cm2
Stress in rivets Shear 1025
Bending 1890 kg/cm2
Bearing stress Bronze- 220 kg/cm2
Bushing
Stress in Bolts Shear 945 kg/cm2
Bearing 2115 kg/cm2

87. :
RADIAL GATE CONSIST OF SKIN PLATE
SUPPORTED BY VERTICALS WHICH IN
TURN REST ON HORIZONTAL GIRDER.
THE HORINZONTAL GIRDERS ARE MOUNTED
ON END ARMS WHICH TRANSMIT HYD.
PRESSURE TO ANCHOR TIES (RODS)
THROUGH ANCHOR GIRDER.
ANCHOR GIRDER TRANSMIT THE LOAD TO
PIER THROUGH ANCHOR TIES.
THUS HYD. PRESSURE RESISTED BY SKIN
PLATE IS ULTIMATELY TRANSMITAD TO PIER
CONCRETE.

88. THE SKIN PLATE & STIFFENERS SHALL BE
DESIGNED TOGATHER IN A COMPOSITE
MANNER.
THE STIFFENERS GENERALLY USED ARE
TEES, ANGLES OR CHANNELS.
THE MINIMUM THICKNESS USED IS “ 8 “
mm.
TO TAKE CARE OF CORROSION , THE
ACTUAL THICKNESS OF SKIN PLATE BE
PROVIDED AT LEAST 1.5 mm. MORE THAN
THICKNESS REQUIRED.

89. MINIMUM NOS. BE USED TO SIMPLIFY THE FABRICATION ,
ERECTION & MAINTANANCE OF GATES.
NOS. TO BE FINALISED BY FOLLOWING CRITERIA :
GATE HEIGHT NO. OF GIRDERS
UP TO 8.0 M. 2
8.0 TO 12.5 M. 3
ABOVE 12.5 M. 4
MAY BE SPACED AS B.M. IN VERTICAL STIFFENERS AT
GIRDER SUPPORT ARE NEARLY EQUAL.
IT SHOULD BE SUITABLY BRACED TO ENSURE RIGIDITY.
IT SHALL BE CHECKED FOR SHEAR AT POINTS WHERE
THEY ARE SUPPORTED BY ARMS.

90. THE NO. OF PAIR OF ARMS SHALL BE EQUAL TO
NO. OF HORI. GIRDERS.
ARMS MAY BE STRAIGHT OR INCLINED.
FOR BIGGER SPAN OF GATE, INCLINED ARMS ARE
PREFFERED.
IT SHOULD BE DESIGNED AS COLUMN FOR AXIAL
LOAD TRASMITTED BY HORI. GIRDER.
THE ARMS ARE SUITABLY BRACED IN SUCH WAY
THAT L/R RATIO OF ARM IN LONGITUDINAL &
TRANSVERSE DIRECTION IS NEARLY EQUAL.
IF THERE IS DIFF. IN H.F.L. & F.R.L., SIDE SHIELDS
ON TOP OF GATE LEAF ARE PROVIDED TO
PROTECT END ARMS AGAINST IMPACT OF WATER.

94. IT CONSIST OF TRUNNION HUB, TRUNNION PIN,
TRUNNION BEARING & TRUNNION BRACKET.
TRUNNION HUB:
IT SHALL ROTATE @ TRUNNION PIN.
ARMS ARE RIGIDLY CONNECTED TO HUB BY
WELDED OR BOLTED CONNECTION.
IT MAY BE CAST STEEL OR M.S.
TRUNNION PIN:
IT SHALL NORMALLY BE SUPPORTED AT BOTH
ENDS OF TRUNNION BRACKET
IT SHALL BE OF CAST STEEL OR FORGED STEEL
WITH CHROME PLATING.

95. TRUNNION BUSH:
IT SHOULD BE OF HIGH TENSILE BRONZE.
THICKNESS OF BUSH = .08 D + 3 MM., “D” IS PIN DIA.
HOWEVER, THICKNESS OF BUSHING IS NOT LESS
THAN 12 mm.
TRUNNION BRACKET:
IT SHALL BE RIGIDLY FIXED TO ANCHOR GIRDER BY
BOLTS.
IT SHALL TRANSFER TOTAL LOAD FROM TRUNNION
TO THE ANCHORAGES.
IT SHALL BE OF CAST STEEL.

96. HUB
A
N
C BRACKET
H GUSSET
O PLATE
R
G
I
R
D TRUNION PIN
E
R LOCK PLATE

97. IT SHALL BE DESIGNED TO WITHSTAND THE TOTAL
WATER LOAD ON GATE & TRANSFER INTO PIERS.
GENERALLY, COMMON ANCHOR GIRDER SYSTEM IS
USED.
IT SHALL BE DESIGNED FOR MAX. LOAD , WHEN
ONE GATE IS FULLY CLOSED & ADJACENT GATE IS
IN FULLY OPEN POSITION.
NOS. OF ANCHORAGES & ROOT DIA. OF THREADED
END OF ANCHORAGES ARE WORKED OUT AGAINST
TOTAL TENSILE LOAD.

100. ANCHORAGES
TRUNION
ASSEMBLY

101. THE EMBEDED LENGTH ARE WORKED OUT FOR BOND
STRESS REQUIREMENT. HOWEVER, MINIMUM LENGTH
OF ANCHORAGES SHALL BE 2/3 OF RADIUS OF GATE.
WHEN TRUNNION IS KEPT 1/3 HEIGHT OF GATE,
ANCHOR GIRDER IS KEPT IN HORIZONTAL POSITION.
IF TRUNNION IS KEPT ABOVE 1/3 HEIGHT OF GATE,
ANCHOR GIRDER IS KEPT INCLINED AT AN ANGLE “θ”,
SO AS TO KEEP THEM PARALLEL IN DIRECTION OF
RESULTANT LOAD PASSING THROUGH TRUNNION.

102. VERY ACCURATE DESIGN,FABRICATION & ERECTION
ARE REQUIRED TO BE DONE AS TELESCOPIC FAILURE
OF ALL THE GATES WILL TAKES PLACE IN CASE OF
FAILURE OF ANY ONE ANCHOR GIRDER.
TO AVOID CRACKING OF FACE CONCRETE,THEY
SHOULD BE INSULATED TO A MINIMUM OF 500 mm.
LENGTH FROM THE FACE CONCRETE.

103. SILL BEAM: R.S.J. WITH S.S. CLADE PLATE IS
PROVIDED ON OGEE.
BOTTOM RUBBER SEAL : USUALLY, WEDGE TYPE
SEAL & IS FIXED ON THE GATE LEAF WITH CLAMPS.
SIDE RUBBER SEAL : “Z“ TYPE OR MUSICAL KNOTE
TYPE IS USED.
IN BOTH SIDES OF PIER, WALL PLATE WITH
S.S.CLADE PLATE IS PROVIDED.
3 TO 6 mm. CONPRESSION IS GIVEN TO RUBBER
SEALS TO MAKE IT WATER TIGHT.

104. WALL PLATE
SILL BEAM

105. Z‐ TYPE RUBBER
SEAL

106. WIRE ROPE
WALL PLATE SKIN PLATE
TOP PLATE
Z TYPE RUBBER SEAL

107. NORMALLY, ROPE DRUM HOIST IS USED.
IT COMPRISES OF TWO END REDUCTION UNITS
(ERU) & ONE CENTRAL DRIVE UNIT(CDU).
E.R.U. CONSIST OF DRUM & 2 TO 4 SETS OF SPUR
GEARS.
C.D.U. CONSIST OF ELECTRIC MOTOR, MAGNETIC
BRAKE & WORM REDUCTION UNIT. STARTER,
RELAYES, CONDUCTORS ETC. ALSO INCLUDED.

110. NORMALLY, OPERATED BY ELECTRIC POWER FROM
GRID SUPPLY.
DIESEL GENERATOR IS PROVIDED IN CASE OF GRID
POWER FAILED.
MANNUAL OPERATION THOUGH VERY SLOW IS
ALSO POSSIBLE .

111. CONSTRUCTION STAGE OF SPILLWAY PIER :
EMBEDED PARTS:
– LINE LEVEL:
1. LINE LEVEL IN SILL BEAM & WALL PLATE SHOULD BE
PROPERLY MAINTAINED AS PER SPECIFIED
TOLERANCES.
2. IF THE FACE TO FACE DIMENSION IS LESS THAN
REQUIRED, THE GATE COMPONENT LIKE SKIN PLATE,
HORI. GIRDER MAY FAUL WITH WALL PLATE & THE
SKIN PLATE WILL HAVE TO BE CUT & THE RUBBER
SEAL HOLES FOR FIXING WILL GET DISTURBED.

112. CONCRETING OF SPILLWAY PIERS :
WHILE CONCRETING SPILLWAY PIER AS
NECESSARY ALLOWANCE SHOULD BE KEPT FOR
BULGING OF CONCRETE. IF CARE IS NOT TAKEN,
THE PIER WILL GET BULGED AT SOME PLACES &
THE HORI. GIRDERS, ARMS & TRUNNION BRACKET
WILL GET FOULED WITH ADDITIONAL CONCRETE.
3 TO 4 INCHES BULGING / UNEVENNESS HAS BEEN
OBSERVED IN SOME OF CASES, WHICH REQUIRES
ENORMOUS CONCRETE CHIPPING &
CONSEQUENTLY COSTS MORE & HINDERS
ERECTION TIME SCHEDULE.

113. STAGE CONCRETE :
NORMALLY, CONCRETING FOR EMBEDDED PARTS ARE
DONE IN STAGES TO ERECT 1ST & 2 nd STAGE EMBEDDED
PARTS. THE SURFASCE OF PREVIOUS STAGE CONCRETE
SHOULD BE KEPT ROUGH & THE CONCRETING OF NEXT
STAGE SHOULD BE VIBRATED TO HAVE PROPER BOND
BETWEEN STAGE CONCRETE. SOMETIMES, DOWEL BARS
BETWEEN STAGE CONCRETE MENTIONED IN DRG ARE
NOT PROVIDED. IN THAT CASE, IT IS FEARED THAT DUE
TO INSUFFICIENT BOND, THE LAST STAGE CONCRETE
MAY GET COLLEPSED. IF NOT COLLAPSED, LEAKAGE
MAY OCCUR THROUGH STAGE CONCRETE SURFACE, IF
PROPER BOND IS NOT ATTAINED BETWEEN TWO STAGE
CONCRETE.

114. IN CASE OF BONDED MAIN ANCHORAGES, THE
INITIAL 1.5 TO 2.0 m LENGTH NEAR ANCHOR
GIRDER IS REQUIRED TO BE INSULATED WITH
GREESE & POLYTHELENE PAPER OR WITH COARK
MASTIC OR ASPHALT TO AVOID SURFACE CRACKING
IN THE PIER.
HOOKS ARE PROVIDED IN BONDED MAIN ANCHOR
RODS AT END.
AS FAR AS POSSIBLE, THE JOINTS IN RODS SHOULD
BE AVOIDED. IF AT ALL IT IS PROVIDED, IT SHOULD
BE DONE WITH PROPER DESIGNED COUPLING &
NOT WITH THE WELDING.

115. STAINLESS STEEL SHEETS/ PLATES ARE CLADED
TO WALL PLATE & SILL BEAM TO HAVE SMOOTH &
NON CORREDED SURFACE FOR RUBBER SURFACE.
THE WELDING SHOULD BE DONE SUCH THAT
THERE WILL NOT BE ANY BURR ON SURFACE. ANY
UN EVEN SURFACE OF CLAD PLATE SHOULD BE
AVOIDED , OTHER‐WISE, IT WILL DAMAGE RUBBER
SEAL.

116. WALL PLATE
S.S. CLADING PLATE

117. (1) SKIN PLATE BENDING :
The bending of skin plate should be done true to its
radius. Instances have been noted of gate failure
because of non‐similarity in radius of gate & skin
plate bending. In such case the load will not be
transferred through trunion centre & gate may get
failed from arm assembly.
(2) BENDING OF VERTICAL STIFFENERS :
T‐verticals of gate leaf are bend to get correct radius
through‐out length of vertical height with T‐ bending
machine, not with screw jack.

118. (3) TRUNNION HUB :
Shape/size of trunion hub should be correctly
casted/ fabricated with correct angle.
(4) casting :
All casting of rollers, trunion assembly, gears
etc. should be free from any defects like blow
holes, cracks, gas inclusion etc.

119. Important attendance during erection for
smooth function of gates:
Concreting of sill beam & wall plate block‐out should
not be done before erection of gate leaf other‐wise
there will not be any chance of adjustment in
alignment.
Seals over the gate leaf should not be fixed before
erecting wall plate & seal beam.
Erection of hoist should be completed before on set
of monsoon if the gates are erected. Otherwise, some
latching arrangement has to be installed to keep
gates in fully open position.

120. A no. of occasions questions has been raised
regarding whether we should go for u/s or
d/s suspension type of hoist in case of Radial
Gates.
In Gujarat, all the Radial Gates have been
designed with up‐stream suspension type of
Hoist only, except that for Ukai Project , a
multi purpose project, where in far 51 ft. x 46
ft. size gates down –stream suspension type
of hoist have been designed.

121. Clause 6.5.3 of I. S. 4623 – 2000 regarding
“Recommendations for structural design of
Radial Gates. “ suggest that “ The hoist shall be
so located , that , as far as possible, the hoisting
force is applied to the gate at the largest
possible radius and hoisting angle does not
change much during travel of gate”. This
condition gets satisfied in case of u/s
suspension only.

122. Where as in down stream suspension type of hoist
, the rope is required to be fixed towards the
trunion and during the travel of the gate the
hoisting angle goes on changing a considerable
extent.
Cl. 6.5.4 of the same I.S. 4623‐2000 , also suggests
that “ In the case of hydraulic hoist the connection
to the gate is on d/s of skin plate while in case of
rope drum hoist, the same is generally preferred
on the u/s of skin plate”.

123. Favorable Aspects For U/S Suspension Type
of Hoists:
Lifting efforts on hoist get reduced.
Hoisting angle remains unchanged during travel of gate.
Pier length comparatively gets reduced.
Unfavorable Aspects :
Not easily accessible for inspection and
maintenance . Replacement of wire rope in
emergent condition not possible.

124. Precautionary Measures of U/S Suspension
type hoist considered:
Generally, wire ropes etc. are periodically
inspected/maintained/replaced when reservoir
gets depleted below crest level.
Incase of big sized gates like, 51 ft. X46 ft., 49 ft.
X35 ft., crest stop‐logs are generally being
thought off depending upon low water level . In
case of such an eventuality like failure of wire
rope, which how‐ever being rare occurrence ,
stop‐logs can be lowered and wire ropes get
replaced.

125. Provision for 10 % gates as standby is always
being made. i.e. Contingency of certain gates being
inoperative is kept in view. Thus, When wire ropes
gets snapped, this 10 % provision takes care of.
While selecting for U/S suspension. The ropes
selected should be galvanized one.
The ropes should be well lubricated from time to
time as per the manufacturer’s recommendation.

132. The uninterrupted leakage of water
through side seals of gate which falls
directly on joint point of girder and
arm resulting failure of joint and
finally entire project.

139. GUIDE ROLLER

148. SCALING AT CONECTION

153. Accumulated debris/water/mud should be
clean regularly to avoid corrosion or
jamming at connection of arm and trunnion
assembly.

155. OIL CAP WAS
MISSING

158. Some of the bolts joining the arm and
horizontal girder are found missing which
may result failure of gate due to insufficient
strength of joint .

160. • Over size/additional holes driven during
erection have not been plugged after
completion of erection work. The same must
be immediately plugged to maintain integrity
of anchor girder.

163. ACCUMULATED WATER
ACCUMULATED WATER

164. • Due to short length, some of the main
horizontal anchor rods are not fastened with
anchor girders, which may ultimately resulted
into failure of anchoring arrangement of gate to
pier.

165. • Some of the main anchor rods are not
extended/bolted up‐to D/S flange of anchor
girder which may be resulted into failure of
anchoring system of radial gates.

167. The vertical anchor rods of gates are not
properly bolted with pedestal base plate of
anchor girder to the base plate of pier, ultimately
up‐thrust/down‐thrust may overturn the
anchoring system of radial gates. This point may
please be immediately attended to complied
with to ensure the safety of gate.

168. • The pedestal connectivity of anchor girder
seemed to be weaker in terms of not
providing requisite no. of studs as specified by
designers on drawing.

171. • Trunnion pin sheath cover is not
provided in most of the gates. It
should be provided to avoid
jamming of mud etc.

172. SHEATH COVER

174. In some of the gates, the guide
rollers are not properly fitted in
position. It should be rectified as per
drawing.

176. • Lubrication of various parts of gate were not
properly done as per norms.

180. In many projects various parts of gate,
footbridge, hoist platform were heavily
corroded due to lack of maintenance.

185. In many projects hoist platform were not
duly bolted to the anchorages embedded in
to pier with their respective base plate. As a
result undue vibrations shall occur in hoist
platform

188. • The base frame of ERU/CDU were not
directly rested on cross girders of hoist
platform. Due to that, excessive vibration
observed on hoist platform.

191. In many project dial gauge indicators
were not properly working.

193. SECOND STAGE CONCRETE FOR FIXING
WALLPLATE WAS INFERRIOR QUALITY

197. BASE PLATE
WALL PLATE

201. EQUILIZER PLATE

203. TOLERENCES FOR COMPONENTS OF GATES
COMPONENTS TOLERENCES
( 1 ) Guide roller/Guide Shoe: +1.00 mm.
Distance between centre line of gate ‐‐ 2.00 mm
& face of side seal.
( 2 ) Side Seal ;
Distance between centre line of gate & + 1.00 mm. to – 1.00 mm.
face of side seal
( 3 ) Trunion bearings :
(a) Co linearity of centre lines of both + 0.25 mm. to – 0.25 mm.
the trunion bearings
(b) Horizontality of centre lines of
both the trunion bearings + 0.25 mm. to – 0.25 mm.
(c) Parallel distance of centre line of
both the trunion bearings from + 3.00 mm to – 3.00 mm
upstream bottom edge of skin plate
(d) Tolerances in diameters of pin, To suit diameters and required fits
bush hub and bracket of trunion
assembly

204. TOLERENCES FOR EMBEDED PARTS
COMPONENTS TOLERENCES
(A) Wall Plate & Sill Beam
(a) Distance Between centre line of +0.00 mm
opening & face of wall plate at sill end. ‐2.00 mm.
(b) Distance Between Centre line of + 2.00 mm.
opening & face of wall plate at top end. ‐ 0.00 mm.
(c) Straightness of face of wall plates & Offset at joints to be ground smooth
sill plates.
(d) Normally of face of wall plates to + 0,00 degree
gate sill & centre line of trunion ‐ 0.00 degree
bearings.
(e) Alignment of sill plate in horizontal + 0.25 mm. TO – 0.25 mm.
plane.