Chashma Barrage Design (2020-MS-CEH-114) PDF

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Barrages of Pakistan complete assignment provides you knowledge of designing in hydraulics and irrigation engineering. Hope it will be very helpful for all students....

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1

HYDRAULIC STRUCTURE (LAB) CHASHMA BARRAGE DESIGN

Submitted By:

Ahtesham Mustafa 2020-MS-CEH-114

Submitted To:

Sir. Sohail Sakhani

UNIVERSITY OF ENGINEERING AND TECHNOLOGY LAHORE

2 3

Table of Contents

Barrage .................................................................................................................................................. 3 3.1

Existing Barrages of Pakistan: ....................................................................................................... 3

3.2

Chashma Barrage: ......................................................................................................................... 3

3.3

Design of Chashma Barrage: ......................................................................................................... 4

3.3.1

Input Design Data:................................................................................................................. 4

3.3.2

Minimum Stable Wetted Perimeter ..................................................................................... 4

3.3.3

Calculation of Lacey's Silt Factor ........................................................................................... 5

3.3.4

Fixation of Crest Level ........................................................................................................... 5

3.3.5

Design of Under sluices ......................................................................................................... 6

3.3.6

Determination of Water Levels and Energy Levels ............................................................... 6

3.3.7

Fixation of d/s Floor Levels and Length of d/s Glacis and d/s Floor .................................... 7

3.3.8

Fixation of d/s floor levels for under sluices using blench curves ........................................ 8

3.3.9

Fixation of d/s floor level for normal barrage section using ................................................. 8

3.3.10

Fixation of d/s floor length for under sluices ...................................................................... 10

3.3.11

Check for Adequacy for d/s floor levels using conjugate depth method. ..........................12

3.3.12

Scour Protection..................................................................................................................13

3.3.13

Inverted Filter Design .......................................................................................................... 16

3.3.14

Design of guide banks ......................................................................................................... 16

3.3.15

Determination of levels of guide banks .............................................................................. 16

3.3.16

Design of Guide Bank Apron ............................................................................................... 17

3.3.17

Fixing of Depth of Sheet Piles .............................................................................................17

3.3.18

Calculation of Exit Gradient ................................................................................................ 18

3.3.19

Calculation For Floor Thickness: .........................................................................................19

2.4 Sketches: .........................................................................................................20

Barrage A barrage is a type of low-head, diversion dam which consists of a number of large gates that can be opened or closed to control the amount of water passing through. This allows the structure to regulate and stabilize river water elevation upstream for use in irrigation and other systems.

2.5 Existing Barrages of Pakistan: 1. Chashma Barrage 2. Jinnah Barrage 3. Taunsa Barrage 4. Trimu Barrage 5. Rasul Barrage 6. Islam Barrage 7. Panjnand Barrage 8. Sulemanki Barrage 9. Khanki Barrage 10. Marala Barrage 11. Balloki Barrage 12. Sidhnai Barrage 13. Guddu Barrage 14. Sukker Barrage 15. Kotri Barrage

2.6 Chashma Barrage:  Chashma Barrage was constructed in 1971.  It is constructed on River Indus near the village of Chashma, about 35 miles downstream of Jinnah Barrage.  It was constructed to divert the water released from Tarbela into River Jhelum through the Chashma Jhelum Link Canal, which has a capacity of 21,700 cusecs. The barrage was also designed to feed the Paharpur canal that is located on the right side.  The river valley at Chashma is 6.5 miles wide.  The barrage is 3,536 feet long with 3,120 feet of clear waterway and with a maximum design discharge of 1.1 million cusecs.

 The total designed withdrawal for canals is 26,700 cusecs.  The maximum flood level height of Chashma Barrage is 37 feet.  The barrage has 52 bays, each 60 feet wide.  The length of the left and right guide bank is 4,302 ft.

2.7 Design of Chashma Barrage: 2.7.1 Input Design Data: For discharge calculation I used my registration no.114 =900000-(114*1000) = 786000 cusecs Maximum Discharge, Q max Minimum Discharge, Qmin River Bed Level, RBL High Flood Level, HFL Lowest water level, LWL Numbers of canals on left side Numbers of canals on right side Maximum Discharge of one Canal Slope of river Lacey's Looseness Coefficient, LLC

2.7.2 Minimum Stable Wetted Perimeter

786000 12000 605 628 587 1 1 3500 1 1.8

cusecs cusecs ft ft ft

cusecs ft/mile

Wetted perimeter, Pw = 2.67√ Qmax Width between abutment, Wa = LLC x Pw Number of bays Bay width Number of fish ladder Width of one fish ladder Number of divide walls Width of one divide wall width of one pier Total number of piers Total width of bays Total width of piers Width between abutment, Wa Discharge between abutments, qabt Discharge over weir, q weir 2.7.3 Calculation of Lacey's Silt Factor S = (1/1844) x f**5/3 / Q**1/6 Lacey's silt factor, f

2367 4261 52 60 1 26 2 15 7 49 3120 343 3519 223.36 251.92

ft ft ft ft ft ft ft ft ft cusecs/ft cusecs/ft

2.14

2.7.4 Fixation of Crest Level Afflux Height of crest above river bed, P Scour depth, R = 0.9(qabt**2 / f)**1/3 Depth of water above crest, Ho = R- P Approach velocity, Vo = qabt / R Energy head, ho = Vo**2 / 2g Eo = Ho + ho Do = HFL - RBL E1 = Do + ho + Afflux Level of E1 = RBL + E1 Crest level = Level of E1 - Eo Maximum d/s water level h = d/s WL - Crest Level Using Gibson Curve h / Eo C' / C

3 6 25.73 19.73 8.68 1.17 20.90 23.00 27.17 632.17 611.27 628 16.73 0.80 0.79

ft ft ft ft ft/s ft ft ft ft ft ft ft ft

C C' = (C'/C) x C

3.8 fps 3.00

Q = C' x W clear x Eo**3/2

894698 cusecs O.K

2.7.5 Design of Under sluices Difference between undersluices & main weir Number of undersluices (N1) Number of bays for one undersluices (N2) Flow through undesluices as % of main weir Crest level of undersluices b1 = N1 x Bay width qus = % flow x q weir Scour depth, R = 0.9(qus**2 / f)**1/3 Do, (may be Do = R) Approach velocity, Vo = qus / R Energy head, ho = Vo**2 / 2g Maximum U/S E.L = HFL + Afflux + ho Eo = U/S E.L - Crest Level h = (U/S E.L - Afflux) - Crest level h / Eo Using Gibson Curve C' / C C' = (C'/C) x C

3 11 5 120 608.27 300 302.308 31.48 23 9.60 1.43 632.43 24.16 21.16 0.88

Q1 & Q3, ( Q = C' x Wclear x Eo**3/2) Q main weir = C' x (Wclear(bays) - Wclear( us) )x Eo**3/2 Total Discharge = Q1 + Q3 + Q main weir %water through undersluices=(Q1+Q3)/Qmain weir*100 Hence Crest Level of Undersluices Number of Bays on Each Side

1057190 -51617 1005573 -2048.1

cusecs cusecs cusecs %

608.27 5

ft

2.7.6 Determination of Water Levels and Energy Levels Check for main weir

ft

% ft ft cusecs/ft ft ft ft/sec ft ft ft ft

0.71 2.70

O.K 1

Check for under sluices

2.7.7 Fixation of d/s Floor Levels and Length of d/s Glacis and d/s Floor Q

qclear

(cusecs)

(cusecs/ft )

(ft)

(ft)

380.9 305.4 260.1

638.39 636.09 633.80

313.8 255.1

633.10 630.28

Normal state of river 943200 786000 393000 For Retrogressed state of river 943200 786000

USEL (USWL+ho )

DSEL hL (DSWL (USEL+ho) DSEL)

E2 (blench curve)

DSFL (DSEL - E 2)

(ft)

(ft)

(ft)

636.39 634.59 632.30

2.00 1.50 1.50

25.3 21.9 19.3

611.09 612.69 613.00

630.10 628.78

3.00 1.50

22.2 19

607.90 609.78

393000 For accreted state of river 943200 786000 393000

Hence d/s Floor level

139.4

625.15

624.15

1.00

13.1

611.05

310.3 277.1 203.6

631.46 629.86 626.09

627.46 624.86 620.59

4.00 5.00 5.50

22.1 20 16.3

605.36 604.86 604.29

=

604.00 ft

2.7.8 Fixation of d/s floor levels for under sluices using blench curves Q

qclear

(cusecs)

(cusecs /ft)

USEL DSEL (USWL+ (DSWL ho) +ho)

hL (USELDSEL)

E2 (blench curve)

DSFL (DSEL E 2)

(ft)

(ft)

(ft)

(ft)

(ft)

Normal state of river 1332199 For Retrogressed state of river

403.70

633.67

630.67

3.00

27.5

603.17

1335576 For accreted state of river

404.72

631.20

623.70

7.50

26.5

597.20

1694686

513.54

634.97

633.77

1.20

28.4

605.37

Hence d/s Floor level for undersluices

597.00 ft

2.7.9 Fixation of d/s floor level for normal barrage section using Crump's method and determination of floor length Q

78600 cusecs

0 Maximum DSWL USWL USEL DSFL RBL Crest level Dpool (Max. DSWL - DSFL) d/s Velocity (Q/(Dpool x Wa)

633.50 635.00 651.73 604.00 605 611.27 29.5 7.57

d/s velocity head (V2/2g) DSEL (DSWL + velocity head) K (USEL - Crest Level ) L (USEL - DSEL )

0.89 634.39 40.46 17.34

ft ft ft ft cusecs/f 251.92 t

q (Q / Total width of bays) Critical Depth, C, (q2 / g)1/3 L/C (K+F)/C ,(from crumps curve) F, [(K+F)/C x C - K] Level of intersection of jump with glacis = Crest level - F

12.54 ft 1.38 3.3 0.92 610.35 ft

E2, ( DSEL - Level of intersection of jump) Submergency of jump, (Level of intersection of jump - DSFL ) Slope of d/s glacis Length of glacis d/s of jump, (slope x submergency)

24.04 6.35 1: 19.06

Length of stilling pool, (4.5 x E2) Length of d/s floor, (Length of stilling pool -Length of glacis d/s of jump)

ft ft 3 ft

108.16 ft 89.10 ft Sa y

Q Minimum DSWL USWL USEL DSFL RBL Crest level

ft ft ft ft ft ft ft ft/sec

786000 623 628 644.73 604.00 605 611.27

90 ft

cusecs ft ft ft ft ft ft

Dpool (Min. DSWL - DSFL) d/s Velocity (Q/(Dpool x Wa)

19 ft 11.76 ft/sec 2.15 625.15 33.46 19.58 251.92

d/s velocity head (V2/2g) DSEL, (DSWL + velocity head) K (USEL - Crest Level ) L (USEL - DSEL ) q (Q / Total width of bays)

ft ft ft ft cusecs/ft

12.54 ft 1.56 3.7 12.93 ft

Critical Depth, C, (q2 / g)1/3 L/C (K+F)/C ,(from crumps curve) F, [(K+F)/C x C - K] Level of intersection of jump with glacis = Crest level - F

598.34 ft

E2, ( DSEL - Level of intersection of jump) Submergency of jump, (Level of intersection of jump - DSFL ) Slope of d/s glacis Length of glacis d/s of jump, (slope x submergency)

26.81 5.66 1: 16.98

Length of stilling pool, (4.5 x E2) Length of d/s floor, (Length of stilling pool -Length of glacis d/s of jump) Say

ft ft 3 ft

120.63 ft 137.61 ft 138.00 ft

2.7.10 Fixation of d/s floor length for under sluices Q Maximum DSWL USWL USEL DSFL RBL Crest level Dpool (Max. DSWL - DSFL) d/s Velocity (Q/(Dpool x Wa)

126862 9 627 630 637.73 597.00 605 608.27 30 12.8

d/s velocity head (V2/2g) DSEL (DSWL + velocity head) K (USEL - Crest Level ) L (USEL - DSEL )

2.55 629.55 29.46 8.18

q (Q / Total width of bays)

384.4

cusecs ft ft ft ft ft ft ft ft/sec ft ft ft ft cusecs/f t

Critical Depth, C, (q2 / g)1/3 L/C (K+F)/C ,(from crumps curve) F, [(K+F)/C x C - K] Level of intersection of jump with glacis = Crest level - F

16.62 0.492 1.8 0.46

ft

607.82

ft

E2, ( DSEL - Level of intersection of jump) Submergency of jump, (Level of intersection of jump - DSFL ) Slope of d/s glacis Length of glacis d/s of jump, (slope x submergency)

21.73 10.82 1: 32.45

ft ft 3 ft

Length of stilling pool, (4.5 x E2) Length of d/s floor, (Length of stilling pool -Length of glacis d/s of jump)

98

ft

65.35

ft

66.00

ft

Q Minimum DSWL USWL USEL DSFL RBL Crest level Dpool (Min. DSWL - DSFL) d/s Velocity (Q/(Dpool x Wa)

126862 9 614.8 616 623.73 597.00 605 608.27 17.8 21.60

cusecs ft ft ft ft ft ft ft ft/sec

d/s velocity head (V2/2g) DSEL (DSWL + velocity head) K (USEL - Crest Level ) L (USEL - DSEL )

7.24 622.04 15.46 1.69

q (Q / Total width of bays)

384.4

Sa y

2

1/3

ft

ft ft ft ft cusecs/f t

Critical Depth, C, (q / g) L/C (K+F)/C ,(from crumps curve) F, [(K+F)/C x C - K] Level of intersection of jump with glacis = Crest level - F

16.62 0.102 0.95 0.33

ft

607.94

ft

E2, ( DSEL - Level of intersection of jump)

14.10

ft

ft

Submergency of jump, (Level of intersection of jump - DSFL ) Slope of d/s glacis Length of glacis d/s of jump, (slope x submergency)

10.94 1: 32.83

ft 3 ft

Length of stilling pool, (4.5 x E2) Length of d/s floor, (Length of stilling pool -Length of glacis d/s of jump)

63

ft

30.63

ft

31

ft

138

ft

Sa y Hence we shall provide d/s floor length =

2.7.11 Check for Adequacy for d/s floor levels using conjugate depth method.

2.7.12 Scour Protection

2.7.13 Inverted Filter Design Size of Concrete blocks Thickness of shingle (3' - 6") Thickness of coarse shingle (3/4" - 3") Thickness of fine shingle (3/16" - 3/4") Spacing b/w conc. Blocks filled with fine shingle

2.7.14 Design of guide banks

2.7.15 Determination of levels of guide banks Merrimen's backwater formula

4 9 9 6 2

ft cube in in in in

2.7.16 Design of Guide Bank Apron

2.7.17 Fixing of Depth of Sheet Piles

2.7.18 Calculation of Exit Gradient

Let the water be headed up to Max. accreted level u/s and no flow d/s. Retogression DSFL Differential head causing seepeage, H = Max. u/s WL - (DSFL - Retrogression)

Depth of d/s sheet pile, d = DSFL - RL of bottom of d/s sheet pile Total length of concrete floor = b

α = b/d 1 form α ~

 

GE

1

 

curve

628.0 ft 4 ft 604.0 ft 28.0 ft 56.0 ft 232.92 ft 4.16 0.153 0.077 SAFE

2.7.19 Calculation For Floor Thickness:

2.8 Sketches:...