Barrage Design

input values

Specific gravity of particles (G)=

2.65

porosity (n) =

seepage head (H) =

0 .4

Critical Hydraulic Gradient (icr) =

(1-n)*(G-1) 0.99

1733.5 2 6 7

5 1731.5

6 .2

6 .2 1725.3 30

1)

Bligh's Theory Creep coefficient (C) = seepage head (H) = Creep length (L) = H/L =

7 (a (assumed)

12.5 m 90.62153

(U/S - D/S) >=

8 7 .5

OK

0 .1 3 7 9 3 6

Uplift Pressure & Thickness Pt H' l 1 6.50 0 2 6.50 8 3 6.50 17 4 12.50 3 5 .8 2 5 12.50 4 9 .2 2 6 12.50 7 7 .2 2 7 12.50 9 0 .6 2 1 5 3

H'-H/L*l 6 .5 5 .3 9 6 5 0 9 4 .1 5 5 0 8 3 7.55891 5 .7 1 0 5 6 3 1 .8 4 8 3 4 7 0

t 5 .2 5 3 4 .3 6 1 3 .3 5 8 6 .1 0 8 4 .6 1 5 1 .4 9 4 0 .0 0 0

FRL =

1746

12.5 m

RBL =

1739.5

2.5 3

1737 2

1 3.5 1733.5

10 4

18

1725.3

width ofeach cutoff =

1m

MDDL = 1742 FRL = 1746 (consider @ U/S) HFL = 1748 water level @ D/S) = 0 particle size (mm) = silt factor (f) =

0.5 1.2445079

design discharge (Q)=

1800 cumecs

Lacey's waterway (P)= Provided length of barrage structure = looseness factor = Scour depth (R) =

0.297678

say at U/S = at D/S =

1R 1.5 R

204.9195 m 61 m <1

0.473(Q/f)^1/3 1.35(q^2/f)^1/3

Hence scour depth (R) =

(1 in 100yrs)

>1 <1

Q= q= f=

1800 29.5082 1.244508

11.984769 12 m 12 m 15 m

min EL for cut off reqd = min EL for cut off reqd =

(HFL - scou 1736 1733

(cutoff should go below this level)

)

input values

Specific gravity of floor (G) = Specific gravity of particles =

2.5 2.65

porosity (n) =

Max static h (take diff b/w U/S HFL a

0.4

Critical Hydraulic Gradient (icr) =

(1-n)*(G-1) 1732.5

0.99

1727

Elementary profiles FLOW (A)

U/S pile 72 d= b= a=

6.000

6m 72 m 12.000 2

1+sqrt(1+a ) = 2

l= fD =

82.14 %

fC =

77.93 %

6.521

FLOW (B) 5.500

Intermediate pile 45 b1 = b2 =

27 27 m 45 m

45 (2/3 of total  =

d=

5.5 m

a1 = a2 =

4.909 8.182

l=

6.626

l1 =

-1.616

fE =

62.920 %

fD =

57.844 %

fC =

-2.961 %

5.5

FLOW (C)

D/S pile 5.5

(III)

72 d=

5.5 m

b=

72 m

a=

13.091

l=

7.065

fE =

24.56 %

fD =

17.14 %

Slope Correction ± (bS) * C'

C=

b' +

downslope

bS =

sloping length

-

upslope

b' =

distance b/w piles

bS =

21 m

b' =

27 m

C' =

4.5

C=

3.5 %

(I/M)

Corrected pressure

Uplift Pressure

Thk(m)

U/S =

fC =

81.853 %

2.74 m

1.8247665

I/M =

fE =

64.113 %

2.14 m

1.4292895

fC =

25.086 %

0.84 m

0.5592593

fE =

21.345 %

0.71 m

0.4758586

2.61 m

1.737

D/S =

Just b4 glacis =

G= G-1 =

2.5 1.5

Upstream Protection w C/C Blocks :

EXIT GRADIENT design depth of scour b H=

3.344 m

(length for C/C blocks) d=

5.500 m

Stone protection lengt 7.065

l= GE

=

0.073

FOS =

13.73

ENERGY DISSIPATOR Q = CLH

3/2

Using discharge equati (sill edges should be pro

Assume crest level =

1739.5 m

Velocity head Ha =

1747.34

HFL U/S = HFL D/S =

1744 (by Discharge-rating curve)

Drowning ratio = Hence C =

57.37 %

1.75 (Fig 1, IS 6966)

Discharge intensity q=

U/S TEL =

1748.34

D/S TEL =

1744.382

Assumed afflux = HL =

4.46 m

Ef2 = Ef1 =

11.8 m 16.26 m

y1 =

2.7655768 m

yc =

5.9099604 m

Froude No F1 =

3.1239165

y2 =

10.913213 m

Ef2 calc=

11.779817 m

(from Blench curves)

(goal seek Ef1) =

<

D/S cistern level =

Lb/y2 =

Assumed retrogression

4.5 Basin 1

Calc HL =

1732.582

4.1 (Fig 8A, IS 4997)

Length of basin = Height of end sill = 0.2Xy2 =

Lb =

45 m 2.2 m

16.260008

ead = nd D/S HFL)

3.34 m

barrage top surface

RBL =

1739.5

6

3 1 7.00

1733.5 21 floor length) 48

1727

U/S

HFL =

1747.34

D/S

HFL =

1744

design discharge (Q)=

1800 cumecs

silt factor (f) =

3.9354796

Lacey's waterway (P)=

204.9195 m

Provided length of barrage structure = looseness factor LF= Scour depth (R) =

at D/S =

1.25 R

<1

0.473(Q/f)^1/3 1.35(q^2/f)^1/3

LF>1 LF<1

45.000 m2/s

Hence scour depth (R) = (20% conc factor) =

1R

61 m

0.297678

discharge intensity q =

at U/S =

(1 in 100yrs)

12.982 16.2275

10.8179 m 12.982 m Deepest scour level= min EL for cut off reqd = min EL for cut off reqd = (cutoff shou

SUPERIMPOSED PRESSURE

24.56

FLOW

-2.961 62.920

77.93

6

6

17.14

82.14 57.844

(I)

Thickness correction U/S pile =

fC =

1.753 %

I/M pile =

fE =

-2.307 %

fC =

27.639 %

fE =

-2.696 %

D/S pile =

(II)

Provided thickness(m)

2.168 %

d=

3.5 m

D=

10 m

b= b' =

72 m 27 m

Effect of U/S pile on I/M pile =

2

±19

3.000 m -3.500 m

b=

72 m

b' =

27 m

b=

D : of

b' =

↑ ↓

+ -

(U/S pile is above the interference level)

-0.515 % 3.50 m 3.500 m

(d+D) * b

d: on

0.000 %

d= D=

Effect of I/M pile on D/S pile = d= D=

2.5

C=

Mutual Interference Correction

Effect of I/M pile on U/S pile =

2.5

d = depth of   D = depth of  

b= b' =

72 m 45 m

Effect of D/S pile on I/M pile = d= D= b= b' =

0.409 % 3.000 3.000 72 45

m m m m

UPLIFT PRESSURE AT SALIENT POINTS glacis 0.71

0.84 2.14 6.0 m 21.0 m

<

Provided 2.5

orks

Downstream Protection Works

1500 X 1500 X 900

C/C Blocks :

6m

elow floor level D =

1500 X 1500 X 900

design depth of scour below floor level D =

D=

6m

(length for C/C blocks) = 2 D =

= 1.5 D

9m

Stone protection length = 2.25 D

ns and known variables, H = vided with radius = H, IS 6531 cl 4.3.3)

7.844 m

Hd =

6.962 m

11 12.375

width of pier = 0.267 Hd =

1.86 say 

2

0.882 m min width of sill reqd = 2/3 * H = say 

45.000 m2/s

1m =

0.5 m

4.480190767 m

 Applying formula

Lb =

5(y2-y1)

41 m

5.23

6

(HFL - scour) 1734.37 1727.78 ld go below this level)

(initial-final) along flow direction -

away from thickness

+

towards thickness

sqrt(D/b') full length length b/w piles pile "of" from junction of "on" with floor soffit

FLOW 2.74

5.5 m m m

m

m

(IS 6531, cl 4.3.2)

input Discharge Q =

1800 cumecs

(coeff of discharge) Cd =

1.75

Le =

effective length of waterway =

Assuming Le = L =

3/2

Q = CLeH

L - (N*KP + Ka)H 48 m

Effective head H =

H=

H=

7.714881 m Le =

46.84277 m

Le =

46.82379 m

7.841426 m

7.843545 (value nearly converges)

Hence Take H =

Discharge I design disc

7.844 m

Velocity Head assumed particle size = Silt Factor f =

5

mm

3.93548

Lacey's scour depth R =

10.81788 m

Velocity of Flow =

4.159782 m

Velocity head Ha =

0.881946 m

Total waterway between end walls =

ntensity q = harge = (+20% conc)

Hd =

58 m

width of each bay = No of bays =

8m 6

Clear wate

width of each pier =

2m

Pier contra

No of piers (N) =

5

Abutment

37.5 m2/s 45 m2/s

6.962054 m

width of pier = 0.267 Hd =

1.858868 m say  2m (IS 6531, cl 4.3.2)

way =

48 m

ction coefficient KP=

0.01

ontrac. Coeff Ka =

0.1

He =

6.818

Hd =

4.7

6.922257

x=

0.319395

EQ =

2.939986

2.94