Design of Trash Rack

a)

Design of Semi Circular Intake Supporting Structure 1 Bellmounth Opening & Transition Size of Opening Slope Angle of center line of HRT with horizontal Co-eff of Contraction

1 in 99.00 0.01 rad 0.6 as per IS 9761 Cl.5.1.2

Ø Cc

Design Discharge

Q

Dia of HRT (in org proposal D shaped has been provided) C/s Area of HRT

D Ahrt

Opening Area of Bellmouth Upper Nappe Height

h1

2 108.98264 M 6.631352 m

h2

6.7304541 m

Lower Nappe Height

h1  D (1.21tan   0.0847) 2

1/ 2



1 2 Cos

0.010101

240 cumec 8.5 2 65.38625 M TanØ 0.000102

 1.1tan  

0.791 h2  D  Cos   0.077 tan   

Height of Bell Mouth

he =(h1+h2)

be Width of Bell Mouth Profile of Bell mouth & Entry details has to be followed as per IS 9761 Cl 5.1 Vbellmouth Velocity through Bellmouth Minimum Submergence for avoiding vortex Fr Froude Number

Case-1 Case-2 Case-3

limiting value 1to1.5 times the intake ht Submergence ht Using formula Submergence ht from IS 9761 Cl.4.2.1 © taking max value of three cases Bottom level of HRT Base level of Trash Rack MDDL required 2 Trash Rack hydraulic design Trash Bar Design Radius for semi circular intake structure Perimeter of the trash rack Assuming normal velocity through trash rack

h h

R=1.1428be Vnt

13.361806 m 8.1562808 m 2.2021855 m/sec 0.2411626 0.3333333 10.2 8.349764 10.689445 10.689445 2193 2192 2207.9394

m m m m m m m

9.3209977 m 31.415927 1.5 m/sec

taking 1.2

say 2208.00 m

say 10.00 m

Considering hand raking, velocity through trash rack

Vt

Area of waterway required Distance between MDDL to Bottom of HRT Height of trash rack Assuming Trash rack panel width

Anet

Assuming Trash rack panel height

TRPh

Thickness of Trash bar

TBt

10.00 mm

Spacing of Trash Bar

TBs

100.00 mm

as per IS 11388 Cl.8.4 limit 40-100 mm

The depth of Trash Bar Unsupported length limiting value as per code IS11388 Provided Unsupported length

TBd

50 mm 700.00 mm 500.00 mm

as per IS 11388 Cl.8.5

Differential head acting on trash rack UDL load on trash Bar Maximum Bending moment Yield stress Failure Stress Safe stress Zreq

hd

Zprov Actual Stress Hence Zprov > Zreq Trash Bar Safe Design

TRPw

TBl w BM fy

0.75 m/sec 320 15.00 16.00 4.00

as per IS 9761 Cl.5.3.6

m2 m m m

22.2849 44.5698

4.00 m

6.00 60.00 18.75 250.00 116.25 76.73 244.38 4166.67 4.50

m kg/m N-m N/mm2 N/mm2 N/mm2 mm3 mm3 N/mm2

1.819 11.65182

as per IS 11388 Cl.8.5.1

INTERMIDIATE ISJC 150 Channel Design Section Properties Width of ISJC 150 flange Udl on ISMC channel Maximum bending moment Yield stress Permissible bending stress Zreq Z about xx axis for ISJC150 from Sp 6 -1 Hence Zprov > Zreq Intermidiate ISJC 150 Safe Design

fy σ

Clear Area for Water Way Nos of Intermidiate IMJC 150 horizontal members Area of IMJC 150 Nos of Trash Bars Area of Trash Bars Total restricted area Whole area Clear Area for Water Way Area req Nos of panel considering 50% chocking nos of Panel Total area Velocity if hand raking Velocity should be less than 0.75m/s, hence its OK if mechanical raking velocity ~ 1.5 m/s its not desirable Angle between adjacent piers Nos of bay Nos of row available upto MDDL Nos of row required Safe Arrangement of Trash Rack Semi-Circular Slab thickness of slab total weight of semi circular slab as semi circular slab acts as a one way slab, load on curve beam length of curved beam Udl load on beam

45.00 270.00 5400.00 250.00 165.00 32727.27 62800.00

mm kg/m N-m N/mm2 N/mm2 mm3 mm3 85.98726

9.00 1620000.00 41.00 20500.00 1640500.00 16.00 14.36 160.00 11.14 24.00 344.63 0.70

nos mm2 nos mm2 mm2 m2 m2 m2 nos nos

30.00 6.00 4.00 4.00

degree nos nos nos

0.20 785.40 392.70 31.42 12.50

m KN KN m KN/m

9.00 nos 41.00 nos 1.6405 m2

12.00 nos

a)

Design of Semi Circular Intake Supporting Structure 1 Bellmounth Opening & Transition Size of Opening Slope Angle of center line of HRT with horizontal Co-eff of Contraction Design Discharge

Q

1 in 99.00 0.01 rad 0.6 240

D Ahrt

8.5 65.38625

Opening Area of Bellmouth Upper Nappe Height

h1

108.98264 6.631352

Lower Nappe Height

h2

6.7304541

Ø Cc

Dia of HRT (in org proposal D shaped has been provided) C/s Area of HRT

h1  D (1.21tan   0.0847) 0.791 h2  D  Cos   0.077 tan    2

Height of Bell Mouth

1/ 2



1 2 Cos

 1.1tan  

he =(h1+h2)

be Width of Bell Mouth Profile of Bell mouth & Entry details has to be followed as per IS 9761 Cl 5.1 Vbellmouth Velocity through Bellmouth

Case-1 Case-2 Case-3

Minimum Submergence for avoiding vortex Froude Number limiting value 1to1.5 times the intake ht Submergence ht Using formula Submergence ht from IS 9761 Cl.4.2.1 © taking max value of three cases Bottom level of HRT Base level of Trash Rack MDDL required 2 Trash Rack hydraulic design Trash Bar Design Width between center line of piers

Fr

h h

13.361806 8.1562808 2.2021855 0.2411626 0.3333333 10.2 8.349764 10.689445 10.689445 2193 2192 2207.9394

R=1.42857b

12.142845

Perimeter of the trash rack Assuming normal velocity through trash rack

Vnt

40.840704 1.5

Considering hand raking, velocity through trash rack

Vt

Area of waterway required Distance between MDDL to Bottom of HRT Height of trash rack Assuming Trash rack panel width

Anet

TRPw

0.75 320 15.00 16.00 4.00

Assuming Trash rack panel height

TRPh

Thickness of Trash bar

TBt

10.00

Spacing of Trash Bar

TBs

100.00

The depth of Trash Bar Unsupported length limiting value as per code IS11388 Provided Unsupported length

TBd

50 700.00 500.00

Differential head acting on trash rack UDL load on trash Bar Maximum Bending moment Yield stress Failure Stress Safe stress Zreq

hd

TBl w BM fy

Zprov Actual Stress Hence Zprov > Zreq Trash Bar Safe Design INTERMIDIATE ISMC 150 Channel Design Section Properties Width of ISJC 150 flange Udl on ISMC channel Maximum bending moment Yield stress Permissible bending stress Zreq Z about xx axis for ISJC150 from Sp 6 -1 Hence Zprov > Zreq Intermidiate ISJC 150 Safe Design Clear Area for Water Way Nos of Intermidiate IMJC 150 horizontal members Area of IMJC 150 Nos of Trash Bars Area of Trash Bars Total restricted area Whole area Clear Area for Water Way For mechanical raking Area req for mechanical raking Nos of panel considering 50% chocking nos of Panel Total area Velocity For manual raking Area req for manual raking

fy σ

3.60

6.00 0.60 18.75 250.00 116.25 76.73 244.38 4166.67 4.50

45.00 2.70 5400.00 250.00 165.00 32727.27 62800.00

8.20 1620000.00 41.00 205000.00 1825000.00 14.40 12.58 160.00 12.72 26.00 326.95 0.73

320.00

Nos of panel considering 50% chocking nos of Panel Total area Velocity

25.45 52.00 653.90 0.37

if hand raking Velocity should be less than 0.75m/s, hence its OK if mechanical raking velocity ~ 1.5 m/s its not desirable Angle between adjacent piers Nos of bay Nos of row available upto MDDL Nos of row required Safe Arrangement of Trash Rack Semi-Circular Slab thickness of slab total weight of semi circular slab as semi circular slab acts as a one way slab, load on curve beam length of curved beam Udl load on beam

30.00 6.00 4.44 4.33

0.20 1327.32 663.66 40.84 16.25

0.010101 as per IS 9761 Cl.5.1.2 cumec

M2 M m

2

TanØ 0.000102 0.000123 0.084823 0.291245 0.500026

m

m m m/sec

m m m m m m m

taking 1.2

1.819 12.14285

say 2208.00 m 11.65182

m

say 13.00 m

m/sec m/sec m2 m m m

as per IS 9761 Cl.5.3.6

25.44732 50.89463

m mm

as per IS 11388 Cl.8.5.1

mm

as per IS 11388 Cl.8.4 limit 40-100 mm

mm mm mm

as per IS 11388 Cl.8.5

m KN/m N-m N/mm2 N/mm2 N/mm2 mm3 mm3 N/mm2

mm KN/m N-m N/mm2 N/mm2 mm3 mm3 85.98726

nos mm2 nos mm2 mm2 m2 m2 m2 nos nos m/s m/s

m2

9.00 nos 41.00 nos 1.825 m2

13.00 nos

nos nos m2 m/s

degree nos nos nos

m KN KN m KN/m

26.00 5

10.68944

3.125

10.4

0.79127 0.011111 0.780159 6.631352

0.79104 0.000778 0.791818 6.730454