Page 1 of 8

DESIGN OF CIRCULAR PURE WATER SUMP

NOTATION USED:

CAPACITY OF TANK = Q

DIAMETER OF TANK = D

DEPTH OF WATER IN TANK = h

FREE BOARD WATER IN TANK = FB

TOTAL DEPTH OF TANK = H

WIDTH OF WALK WAY = Ww

THICKNESS OF WALK WAY SLAB = tw

THICKNESS OF VERTICAL WALL @ TOP = Tw

THICKNESS OF VERTICAL WALL @ BOTTOM = Bw

WDTH OF WALL FOOTING = Fw

DEPTH OF WALL FOOTING = Fd

WATER DEPH = Hw

THICKNESS OF WALL = d

HOOP TENSION IN WALL = HTw

REQUIRED STEEL = Ast.req

PROVIDED STEEL = Ast.prv

MINIMUM STEEL ON BOTH THE FACE = 0.24% Ast.min/b.f

MINIMUM STEEL ON EACH FACE =0.12% Ast.min/e.f

DIAMETER OF BAR USED =

REQUIRED SPACING OF STEEL = Sp.req

PROVIDED SPACING OF STEEL = Sp.prv

TENSILE STRESS IN CONCRETE =

TENSILE STRESS IN CONCRETE =

BENDING MOMENT = M

DEPTH REQUIRED = dreq.

f.bar

scc.cal

scc.alw

Page 2 of 8

TANK DIMENSION:

CAPACITY OF SUMP (Q) 1050000 LITERS

1050 Cum

HEIGHT OF TANK PROPOSED (h) 3.4 Mtrs

FREE BOARD PROPOSED (FB) 0.6 Mtrs

TOTAL DEPTH OF TANK (H) 4 Mtrs

REQUIRED TANK DIAMETER (D) 19.83 Mtrs

PROVIDE DIAMETER OF TANK (D) 20.00 Mtrs

HAUNCH DIMENSION WIDTH = 0.15 Mtrs

DEPTH = 0.15 Mtrs

NATURAL GROUND LEVEL (NGL) 599.00 Mtrs

STORAGE LEVEL (SL) 598.20 Mtrs

FINISHED BOTTOM FLORR LEVEL (FFL) 594.80 Mtrs

SPHERICAL DOME AT TOP

DOME EIGHT = D/7 TO D/5 2857.143 TO 4000.000 mm

THEREFORE PROVIDED DOME HEIGHT = 2500.00 mm

THEREFORE DOME RADIUS = [(D/2)^2+h^2]/(2h) 21250.00 mm

MATERIALS:

CONCRETE - M20 & STEEL-Fe-415

PERMISSIBLE STRESS IN CONCRETE & STEEL

(REF - IS:3370, (Part-II)-1965, TABLE-1 & 2)

MODULAR RATIO (m) 13.00

Page 3 of 8

a) DESIGN OF TOP DOME

THICKNESS OF TOP DOME 175 mm

LOADS:

SELF WEIGHT OF DOME = 0.4375 t/m^2

LIVE LOAD = 0.15 t/m^2

TOTAL LOAD = 0.588 t/m^2

0.471

0.882

4.38 t/m

HOOP STRESS = 0.25 N/mm^2 < 1.2 N/mm^2 (IS:3370, Part-II)

6.63 t/m

THERE FORE MERIDONIAL STRESS = 0.38 N/mm^2 < 2.8 N/mm^2

THERE PROVIDE MIN. REINFORCEMENT=0.12% 210 mm^2

DIAMETER OF PROVIDED STEEL 8 mm

SPACING REQUIRED (SP.req) 239.39 mm

THEREFORE PROVIDED SPACING (Sp.prv) 200 mm

PROVIDE 8 MM DIA 200 MM C/C IN BOTH MERIDONIALLY & CIRCUMFERENTIALLY

PROVIDED STEEL (Ast,Pro) 251.328 mm^2

TENSILE STRESS IN EQUIVALENT AREA = 0.59 N/mm^2 < 1.2 N/mm^2 (IS:3370, Part-II)

b) DESIGN RING BEAM

6.63 t/m

THEREFORE HORIZONTAL COMPONENT OF MERIDONIAL THRUST = 5.852 t/m

HOOP TENSION = 58.52 MT

SIZE OF BEAM B = 600 mm

D = 600 mm

AREA OF STEEL REQUIRED (Ast.Req.) = 3901.37 mm^2

DIAMETER OF PROVIDED STEEL = 25 mm

NUMBER BAR REQUIRED = 7.95

THEREFORE PROVIDED NUMBER 8

SINCE RING BEAM IS SUPPORTED THROUGHT, PROVIDE NOMINAL SHEAR REINFORCEMENT OF 8 MM 2-LEGGED BARS @ 200 MM C/C

c) DESIGN OF VERTICAL WALL

THEREFORE, SinF =

THEREFORE, CosF =

THEREFORE, F = 280

HOOP FORCE =WR[CosF-1/(1+CosF)] =

MERIDONIAL FORCE = WR(1-CosF)/(Sin^2(F)) =

MERIDONIAL FORCE = WR(1-CosF)/(Sin^2(F)) =

Page 4 of 8

DIAMETER OF TANK (D) 20.00 Mtrs

DEPTH OF WATER (h) 3.4 Mtrs

THICKNESS OF TANK WALL @ TOP (Tw) 200 mm

THICKNESS OF TANK WALL @ BOTTOM (Bw) 350 mm

THICKNESS OF TANK WALL (for calculation) 275 mm

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HENCE THE RATIO (H^2/D*T) 2.10

DESIGN FOR HOOP TENSION

(Ref:IS3370, Part-IV,TABLE-12)

Hw Hw COEFF HTw Ast.req Ast.min/b.f Sp.req Sp.prv Ast.prv

Mtrs mm T mm^2 mm^2 mm mm mm mm^2 N/mm^2 N/mm^2

0.0H 0.6 222.50 0.074 2.516 167.73 534.00 10 294.16 180 872.67 0.120 1.20

0.1H 0.94 235.25 0.179 6.086 405.73 564.60 10 278.21 180 872.67 0.275 1.20

0.2H 1.28 248.00 0.281 9.554 636.93 595.20 10 246.62 180 872.67 0.408 1.20

0.3H 1.62 260.75 0.375 12.75 850.00 625.80 10 184.80 180 872.67 0.516 1.20

0.4H 1.96 273.50 0.449 15.266 1017.73 656.40 10 154.34 125 1256.64 0.576 1.20

0.5H 2.3 286.25 0.506 17.204 1146.93 687.00 10 136.96 125 1256.64 0.620 1.20

0.6H 2.64 299.00 0.519 17.646 1176.40 717.60 10 133.53 125 1256.64 0.608 1.20

0.7H 2.98 311.75 0.479 16.286 1085.73 748.20 10 144.68 125 1256.64 0.537 1.20

0.8H 3.32 324.50 0.375 12.75 850.00 778.80 10 184.80 125 1256.64 0.404 1.20

0.9H 3.66 337.25 0.21 7.14 476.00 809.40 10 194.07 125 1256.64 0.217 1.20

f.bar scc.cal scc.alw

Page 6 of 8

DESIGN FOR BENDING MOMENT

(Ref:IS3370, Part-IV,TABLE-10)

Hw Hw COEFF M d.req Ast.req Ast.min/e.f Sp.req Sp.prv Ast.prv

Mtrs mm t-m mm mm^2 mm^2 mm mm mm mm^2

0.1H 0.94 235.25 0.001 0.039 35.868 14.32 282.30 10 278.21 180 436.33

0.2H 1.28 248.00 0.0035 0.138 67.104 47.27 297.60 10 263.91 180 436.33

0.3H 1.62 260.75 0.0068 0.267 93.534 86.87 312.90 10 251.01 180 436.33

0.4H 1.96 273.50 0.0099 0.389 112.857 119.99 328.20 10 567.73 180 436.33

0.5H 2.3 286.25 0.012 0.472 124.252 138.34 343.50 10 228.65 180 436.33

0.6H 2.64 299.00 0.0115 0.452 121.636 126.41 358.80 10 218.90 180 436.33

0.7H 2.98 311.75 0.0075 0.295 98.230 78.77 374.10 10 209.94 180 436.33

0.8H 3.32 324.50 -0.0021 -0.083 51.978 -21.12 389.40 10 201.69 180 436.33

0.9H 3.66 337.25 -0.0185 -0.727 154.276 -178.44 404.70 10 194.07 180 436.33

1.0H 4 350.00 -0.0436 -1.714 236.841 -404.04 420.00 10 187.00 180 436.33

DESIGN FOR SHEAR FORCE

(Ref:IS3370, Part-IV,TABLE-11)

SHEAR COEFFICIENT = 0.299

SHEAR FORCE AT BASE = 3.46 MT

SHEAR STRESS = 0.122 N/mm^2

PERMISSIBLE SHEAR STRESS = 1.700 N/mm^2

f.bar

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d) DESIGN OF FLOOR

SLAB IS RESTING ON CONTINUOUS GROUND HENCE PROVIDE 150 MM THICK SLAB

MINIMUM AREA OF STEEL REQUIRED = 0.12% ON EACH FACE = 180.00 mm^2

PROVIDE 8 mm DIA & 250 mm C/C ON BOTH THE FACES & BOTH THE WAYS

e) DESIGN OF WALL FOOTING

WIDTH OF FOOTING BEYOND FACE OF WALL = 450 mm

WIDTH OF FOOTING INSIDE THE TANK BEYOND FACE = 600 mm

TOTAL WIDTH OF FOOTING (Fw) 1400 mm

DEPTH OF FOOTING (Fd) 300 mm

SURFACE AREA OF DOME = 333.84 Sq.M

THEREFORE TOTAL LOAD FROM DOME = 196.13 MT

LOAD PER METER ON WALL FROM DOME = 3.09 t/m

SELF WEIGHT OF RING BEAM = 0.6 t/m

SELF WEIGHT OF VERTICAL WALL =

RECTANGLE PORTION = 2.00 MT

TRIANGULAR PORTION = 0.75 MT

SELF WEIGHT OF FOOTING = 1.05 MT

WEGHT OF WATER = 2.04 MT

TOTAL VERTICAL LOAD PER M = 9.53 MT

MOMENT @ END OF FOOTING

FROM DOME LOAD = 2.163 t-m

FROM RING BEAM = 0.300 t-m

FROM VERTICAL WALL-REC. PORTION = 1.400 t-m

FROM VERTICAL WALL-TRIA. PORTION = 0.413 t-m

FROM SELF WEIGHT. FOOTING = 0.74 t-m

FROM WEIGHT WATER = 2.24 t-m

MOMENT @ BASE OF WALL = -1.71 t-m

TOTAL MOMENT = 5.541 t-m

Page 8 of 8

DISTANCE OF THE RESULTANT FROM END = X = 0.581 m

ECCENTRICITY =(B/2-X) = 0.119 m

SBC OF SOIL = 15 t/m^2

PRESSURE ON SOIL = P/A+or-M/Z

MAXIMUM SOIL PRESSURE = 10.267 t/m^2

MINIMUM SOIL PRESSURE = 3.348 t/m^2

SOIL PRESSURE LESS THEN SBC HENCE OK

MAXIMUM BENDING MOMENT @ FACE OF WALL = 1.040 t-m

DEPTH REQUIRED = 184.464 mm

PROVIDED DEPTH = D-60 = 240.00 mm

AREA OF STEEL REQUIRED = 331.91 mm^2

MIN. ASTEEL REQUIRED ON ECH FACE = 360 mm^2

DIAMETER OF MAIN BARS USED = 10 mm

SPACING REQUIRED FOR MAIN BARS = 218.17 mm

PROVIDED SPACING OF MAIN BARS = 200 mm

DIAMETER OF DISTRIBUTION BARS USED = 8 mm

SPACING REQUIRED FOR DISTRIBUTION BARS = 139.626667 mm

PROVIDED SPACING OF DISTRIBUTION BARS = 125 mm

CHECK FOR ONE WAY SHEAR:

TOTAL SHEAR FORCE = 4.620 T

SHEAR STRESS = 0.221 < 1.7 N/mm^2

(REF:IS3370-Part-II, TABLE-2) HENCE O.K

CHECK FOR TWO WAY SHEAR:

PUNCHING LOAD = 9.53 T

RESISTING AREA FOR PUNCHING = 480000 mm^2

PUNCHING STRESS = 0.199 N/mm^2

PERMISSIBLE PUNC. STRESS =0.16*SQRT(Fck) = 0.716 mm^2

(REF:IS456-2000, Clause-31.6.3)