Spillway is the main part of a dam and its design is somehow very complicated. Here presenting a presentation which enable a civil engineering student to understand design . whole presenta…Full description
Fakultas Teknik, Jurusan Teknik sipil, Matakuliah Sistem Irigasi
PresentationFull description
Fakultas Teknik, Jurusan Teknik sipil, Matakuliah Sistem IrigasiDeskripsi lengkap
Naval EngineeringFull description
Descrição completa
Design of Machine Elements. Virgil Moring Faires. 0023359501 "A new machine is born because there is a real or imagined need for it. It evolves from someone's conception of a device wit…Full description
Design of Machine Elements. Virgil Moring Faires. 0023359501 "A new machine is born because there is a real or imagined need for it. It evolves from someone's conception of a device with which...
Design of Trickling FiltersFull description
Design of Machine Elements. Virgil Moring Faires. 0023359501 "A new machine is born because there is a real or imagined need for it. It evolves from someone's conception of a device wit…Descrição completa
Design of ColumnFull description
Full description
Full description
DESIGN OF OGEE PROFILE
DESIGN NOTE:
UPSTREAM & DOWN STREAM PROFILE OF CREST Markandeya dam is 47 m high and has six spillway radial gates with maximum discharging capacity of 3738 cumec. The spillway has standard WES(Waterways WES(Waterways Experiment Station of U.S Army Engineers) with u/s face has 3H:3V slope and d/s ogee conforming to following equation: 1.78
X
Where
H d
0.78
=
I
1.852 H d Y
=Design head in "m"=
8.00 8.00 m in this this case case
The profile on the upstream is intended to add more weight on stability consideration.
X & Y are co-ordinates of ogee profile with respect to crest as axis and down ward being positive & right side is +ve as indicated in the figure below.
crest axis
0,0
+X
3 1.78
X
3
0 .78
=
1.852 H d Y
+Y
The upstream profile is conforming to the table given below:
X/Hd
0.0000
-0.0200
-0.0400
-0.0600
-0.0800
-0.1000
-0.1200
-0.1600
-0.1700
-0.1800
-0.1900
-0.2000
Y/Hd
0.0000
0.0004
0.0016
0.0036
0.0065
0.0103
0.0150
0.0275
0.0313
0.0354
0.0399
0.0450
X
0.0000
-0.1600
-0.3200
-0.4800
-0.6400
-0.8000
-0.9600
-1.2800
-1.3600
-1.4400
-1.5200
-1.6000
Y
0.0000
0.0032
0.0128
0.0288
0.0520
0.0824
0.1200
0.2200
0.2504
0.2832
0.3192
0.3600
The d/s slope "m" of dam is fixed as=
0.800 H:1V for stability consideration.
Th etangent point between ogee profile and the d/s slope is obtained by differentiating the ogee profile equation with respect to x and equating the slope to the d/s slope of dam I.e., Differentiating equation -I with respect to x we get,
0.78
1.78 X
dX
1.852 H d
1.78 X 0.78
dY or
0.78
=
=
1.852 H d 0.78
dY dX
1 =
d / s slope
1 =
m 1
Therefore X-cordinate of tangent point=
é1.852 xH d 0.78 ù 0.78 = X = ê ú ë 1.780 xm û
& Y - coordinate from the crest, using the equation -I, =
with crest level at
696.00 m the elevation of tangent point=
11.205
7.869 m
688.131 m
m
ENERGY DISSIPATOR:
The site is not suited for energy dissipator such as ski-jump bucket or roller bucket since the bed of the river is highly jointed and impingement of jet or hydraulic rollers may result in the deep scour.
U.S.B.R. stilling Basin -II is proposed for th energy dissipating system for the following reasons
1 There is daequate depth of tailwater
2 The velocity of water entering the basin is more than 18m/s
3 The discharge per metre length is more than 5.7 cumec.
4 The Froud's No. of flow=F1>4.5
5 The IS4997-1968(4th print 1985) gives guidelines for stilling basin-II conforming to the above requirement, but there is provision for the basin blocks and length of stilling basin is given considering the basin blocks. However clause 4.3.5 suggests that the basin blocks are not recommended if velocity of flow is greater than 15m/s in which case the length of basin can not be obtained from given figure (8A) for basin Therefore USBR stilling basin-II is adopted with increased length of basin.
6 In the Hydraulic Designs Of Stilling basins & Energy Dissipators (U.S.D.I.B.R) By-A.J.Peterka the basin -II is well suited to discharges more than 14 cumec./m length , and the baffle/basin blocks if provided in the stilling basin may result in low pressure on the d/s of basin block which in turn result in cavitation problems.
7 The plan enclosed indiacte the lay out of the USBR Stilling Basin-II which is similar to stilling basin given by IS4997 except for the basin block.
The drawing shown vide by K.N.N.Ltd , Irrigation(N) is for stilling basin-II with basin blocks and length of basin is 48.00 m. This will have to revised.
The details of the various components are as enclosed in the table.
The thickness of basin is based on the assumption that the edges are clamped with anchor rods for two different cases with uplift at MWL condition and varrying from maximum uplift at heel and mnimum(Max.TWL-BL) uplift at the end of stilling bas in. The uplift at toe is computed for designing the thickness of floor.
By way of drainage arrangements thickness for various releases are calculated.
Depth of anchor rods are computed for following cases: 1 The tension within the permissible limit 2 The bond strength between grout and the anchor rod is with in permissble value of 6 kg/sq.cm 3 The bond strength between grout and the rock is with in permissble value of 4 kg/sq.cm 4 The submerged weight of rockcone formed by the anchor rod depth is greater than uplift force
