DESIGN DATAO.D. OF TANK, ( D ) = 6.0m =19.69 ft HEIGHT OF TANK, ( H ) = 7.5m= 24.61 ftSPECIFIC GRAVITY OF LIQUID (SG)= 0.85WEIGHT OF WATER IN TEST CONDITION (WW) = 200 TeEMPTY WEIGHT , (Tank+Bottom Pl.) 11.75+1.96 Te (WE) = 13.71TeTEST WEIGHT, (Weight of water in tank in test condition) WH = WW +WE = 214TeOPERATING WEIGHT, WT =(WW x SG +WE)= 183.71TeSTEEL REINFORCEMENT GRADE FE415CONCRETE GRADE Nominal Mix 1: 1.5 : 3 TANK BASE LEVEL1200 Above FGLS.B.C. OF SOIL AT 2.0m DEPTH=16.74te/m2BASIC WIND SPEED (Vb) = 47 m/sec SEISMIC ZONE III

1.0 CALCULATION OF WIND FORCE (REF IS 875 PART 3)BASIC WIND SPEED (Vb) = 47 m/secK1 = 1 , 50 YEAR OF SERVICEK2 = 1 , CATEGORY 2 CLASS AK3 = 1DESIGN WIND SPEED Vz = Vb X K1 X K2 X K3 = 47 m/sec= 169.2 km/hr = 105.14 mphDESIGN WIND PRESSURE Pz = 0.6 x (Vz)^2 =1325.4 N/m2 = 135.11 kg/m2WIND FORCE ACTING ON THE TANK SHELL =Pz x O.D x Height x SHAPE FACTOR(0.7) = 4252.5 kgCORRESPONDING WIND MOMENT AT BASE M WIND = Wind force x Height /2.0 = 15947kg.m

CALCULATION OF SEISMIC FORCE ( REF IS 1893 ) MOMENT AT BASE OF TANK = ZI { C1WsXs)+ (C1WrHt)+ (C1W1X1) +(C2W2X2)} WHERE,Z = SEIMIC ZONE FACTOR = 0.2, I = IMPORTANCE FACTOR = 1.5 C1 = LATERAL EARTHQACKE COEFFICENT = 0.60 (Ref. API 650 E 3.31 )

CALCULATION OF SEISMIC FORCE ( REF IS 1893 ) (Contd.) CONSTANTD = 19.68 ft, H = 24.60 ftD/H= 0.8FACTOR K = 0.58 ( REF API 650 FIG E 4 )NATURAL PERIOD OF THE FIRST SLOSHING MODE, SECONDT = K ( D ) 0.5 = 0.58 ( 19.68 ) 0.5 = 2.57 sec < 4.5 secSITE COEFFICIENT S = 1.5 HENCE LATERAL FORCE COEFFICIENTC2 = 0.75 S/T = (0.75) x 1.5/2.57 = 0.4377

CALCULATION OF SEISMIC FORCE ( REF IS 1893 ) (Contd.) CONSTANTOPERATING WEIGHT, WT = 185.30 Te = 185300 kg = 407660 lbsH = MAXIMUM DESIGN LIQUID LEVEL = 24.60 ft

REF FIGURE E2 API 650 FOR D/H VALUE OF 0.8, EFFECTIVE MASSESW1 /WT = 0.82 W1 = 0.82 x WT = 0.82 x 407 = 334281.20 lbs W2 /WT = 0.24 W2 = 0.24 x WT = 0.24 x 407660 = 97838.40 lbs

REF FIGURE E3 API 650FOR D/H VALUE OF 0.8, CENTROID OF SEISMIC FORCEX1 /H = 0.44 X1 = 0.44 x 0.24 = 10.824 ft X2 /H= 0.75 X2 = 0.75 x 0.24 = 18.45 ft

WS = TOTAL WEIGHT OF TANK SHELL = 8216 kg = 18075.20 lbs

CALCULATION OF SEISMIC FORCE ( REF IS 1893 ) (Contd.)CALCULATION OF C.G. OF SHELL

SHELLCOURSEHT OF COURSE(cm)THICKNESS(cm)AREA (a)cm2DISTANCE OF CG (Y) FROM BOTTOM (cm)a yt12501.0250 125.0031250.00t21250.6 75312.5023437.50t31250.6 75437.5032812.50t41250.6 75562.5042187.50t51250.6 75687.5051562.50TOTAL--550-181250.00

CALCULATION OF SEISMIC FORCE ( REF IS 1893 ) (Contd.)DISTANCE OF C.G. FROM BOTTOMXS = a1y1+a2y2+a3y3+a4y4+a5y5 a1+a2+a3+a4+a5 = 181250 550 = 329.545 cm = 10.81 ftHT = ACTUAL HEIGHT OF TANK = 24.60 ftWr = WEIGHT OF TANK ROOF = 1130 kg = 2486 lbsM = ZI { (C1WsXs) + (C1WrHt) + (C1 W1 X 1) + (C2W2X2) }ZI = 0.2 x 1.5 = 0.3 C1WsXs = 0.6 x 18075.20 x 10.81 = 117235.75C1WrHt = 0.6 x 2486 x 24.60 = 36693.36C1W1X1 = 0.6 x 334281.20 x 10.824 = 2170955.82C2W2X2 = 0.4377 x 97838.40 x 18.45= 790100.35SUM= 3114985.28

CALCULATION OF SEISMIC FORCE ( REF IS 1893 ) (Contd.)TURNING MOMENT AT BOTTOM OF THE SHELL (SEISMIC)M = 0.3 x 3114985.28 = 934495.6 lbs ft = 127431.21 kg-mTHE MOMENT DUE TO SEISMIC IS MORE THAN MOMENT DUE TO WIND(M WIND=15946.88 kg m), (Ref. Page 1), HENCE SEISMIC MOMENT IS GOVERNING FOR DESIGN OF PAD AND RING BEAM.CHECK OF PRESSURE AT TANK PADCASE-1 = TEST WEIGHT CONDITIONPt = WH /A WH = TOTAL TEST WEIGHT = 215.30 TeA = (/4) D2 = 28.26 m2Pt = 215.30/ 28.26 = 7.62 T/m2 < 20 T/m2 THE TANK IS RESTING ON COMPACTED SAND FILLING SO SBC OF COMPACTED SAND SHALL NOT BE LESS THAN 20 T/m2

CALCULATION OF SEISMIC FORCE ( REF IS 1893 ) (Contd.)CASE-2 = OPERATING WEIGHT + SEISMIC FORCEPressure at tank pad, Po = WT/A + M/Z Z = I/Y = (D^4 /64)/(D/2) = (D3) / 32= 3.14 X 6^3 32= 21.195 m3HERE WT = 185.30 TeM = 127.43 Te.mPo = (185.30/ 28.26) + (127.43/ 21.195) = 6.55 + 6.01Po1 = 12.56 Te/m2 < 1.25 X 20 = 25 Te/m2 (PERMISSIBLE PRESSURE IS INCREASED BY 25% FOR SEISMIC CONDITION) Po2 = 0.54 Te/m2 , SINCE Po2 IS +VE, NO UPLIFTING OF TANK

CHECK OF SOIL PRESSURE AT BOTTOM OF RING BEAM AT 2.0 m DEPTH BELOW FGL

CHECK OF SOIL PRESSURE AT BOTTOM OF RING BEAM AT 2.0 m DEPTH BELOW FGL.FOR CASE 1 (TEST WEIGHT CONDITION)TANK PAD LEVEL IS KEPT 1200 mm ABOVE FINISHED GROUND LEVEL.DENSITY OF SAND TAKEN AS 1.8 t/m3 (Ref. Soil handbook)NET PRESSURE AT FOUNDATION LEVEL Ptf = 7.62 + 1.2 x 1.8 = 9.78 Te/m2 < 13.6 Te/m2 (SBC AT 2.0 m BELOW FGL) FOR CASE 2 (OPERATING WEIGHT + SEISMIC)Pof = 12.56 + 1.2 x 1.8 = 14.72 Te/m2 < 1.25 x 13.60 = 17.0 Te/m2THE ALLOWABLE SHALL BE 17.0 Te/m2 UNDER SEISMIC CONDITIONAS PER EIL STANDARDNET ALLOWABLE PRESSURE OF THE SOIL AT THE FOUNDING LEVEL OF RING WALLpt = w x H + 1.8 x h1HERE w = DENSITY OF FLUID (t/m3); 1.00 t/m3 FOR WATERH = 7.5 m ; h1 = 1.2mpt = (1.0 x 7.5) + (1.8 x 1.2) = 9.66 Te/m2 < 13.60 Te/m2 HENCE O.K.

R.C.C. DESIGN OF RING BEAM

R.C.C. DESIGN OF RING BEAMMAXIMUM PRESSURE AT PAD LEVEL = 12.56 Te/m2 SAY 12.6 Te/m2EQUIVALENT HEIGHT OF SAND (HI) = 12.6/1.8 = 7 mH = 2.0 + 1.2 = 3.2m, D = 6.0 0.3 = 5.7mLATERAL PRESSURE DUE TO FILLED SANDp1 = KA.Y.H = 1/3 x 1.8 x 3.2 = 1.92 Te/m2LATERAL PRESSURE DUE TO SURCHARGE LOADp2 = KA.Y.HI = (1/3) 1.8 x 7 = 4.2 Te/m2 TOTAL LATERAL PRESSURE AT BOTTOM OF RING BEAMP = p1 + p2 =1.92 + 4.2 = 6.12 Te/m2 = 6120 kg/m2HOOP TENSION = P x d/2 = 6120 x 5.7/2 = 17442 kg/mAREA OF STEEL OF HOOP TENSION (At) = 17442/2300 = 7.6 cm2/mUSE 12 AS CIRCULAR RING BARAREA OF 12 = 1.13 cm2 (at)SPACING OF BAR = (at /At) x 100 = 1.13 x 100/7.6 = 14.9 cm c/cAS PER API 650MIN LOOP TENSION AREA = 0.0025 x THICKNESS = 0.0025 x 30 x 100 = 7.5 cm2/mHENCE PROVIDE 12 @ 150mm c/c AS CIRCULAR RING BAR.VERTICAL REINFORCEMENTAS PER API 650MINIMUM AREA OF STEEL FOR VERTICAL BAR = 0.0015 x 30 x 100 = 4.5 cm2USE 12 at = 1.13 cm2SPACING OF BAR = 1.13 x 100/ 4.5= 25.11 cm c/cPROVIDE 12 @ 200mm c/c AS VERTICAL BARREINFORCEMENT IN OUTER FACE OF BEAMPROVIDE SAME REINFORCEMENT AS CALCULATED ABOVE WHICH IS MORE THAN NOMINAL REINFORCEMENT REQUIRED FOR TEMPERATURE AND SHRINKAGE ETC.