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• Gutaiba Almasri

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Steel Welded Tank Dia.:15.75 m 18.00 m Height DESIGN CODE : API 650 Tank Diameter : 18 m =18x3.2808 =59 ft Specific Gravity : G=1.0 Vapour Pressure :22.5 in H2O Sd=22700 psi (Material of onstruction is st 37) St=24900 psi Tank has internal pressure : P= 22.5 in H2O=5.55 kPa= 555 kg/m²

Weight of roof =0.006*0.5*(18*3.14)*(10^2+1^2)^0.5*8000=12283 kg

Design of shell Height of tank shell =16.1 m Liquid filling level =15.78 m

C.A.= 1.2 mm

F.7 and 3.6.3.2 E=0.85 → Design shell thickness td =2.6Dx(H+P/12G-1)xG/Sd+ 0.0472 →

Design shell thickness →

td =0.00676*(H+22.5/12-1) +0.0472

→

tt=0.00616*(H-1)

Hydrostatic test shell thickness

Hydrostatic test shell thickness

tt= 2.6xD(H-1)/St

Height (m) 2 4 6 8 10 11.5 13 14.5 16

(ft) 6.5616 13.1232 19.6848 26.2464 32.808 37.7292 42.6504 47.5716 52.4928

td (in) 0.081767 0.126124 0.17048 0.230541 0.259193 0.29246 0.325728 0.358995 0.392262

(mm) 2.0768924 3.2035453 4.3301983 5.8557329 6.5835042 7.428494 8.2734837 9.1184734 9.9634631

tt (in) 0.034259 0.074679 0.115098 0.155518 0.195937 0.226252 0.256566 0.286881 0.317196

Thickness

(mm) Cosidered 0.87019 6 1.896844 6 2.923499 6 3.950153 6 4.976807 8 5.746798 10 6.516788 12 7.286779 14 8.056769 16

Wt - corr. kg 1176.7 1361.3 1840.0 2488.2 2797.5 3156.5 3515.6 3874.7 4233.7 Total in kg: 20210.5

REMARKS:

DESIGNED BY

CHECKED BY

APPROVED BY

Steel Welded Tank Dia.:15.75 m 18.00 m Height Design of Roof 1) Acording to (3.10.2) the minimum thickness of roof plate is 5mm Take it 6mm 2) Roof structure design: To use 33 IPE200 this means each member will carry the following: Dead weight: 200 Kg Roof plate weight : 300 Kg Live weight :300 Kg Total :900 Kg Z= M/f =800x393.75/1650 =190.9 cm3 from steel table we will find : Zy=194.3 cm3 → IPE 200 is safe Maximum Design Pressure Permitted -Pf- API 650 APPENDIX F Pf =1.6xP- 4.8xth =1.6x22.5-4.8x0.1968= 35.05536 in of water Pf >P OK Let us calculate the weight of the shell without any corrosion : td Wt (in) (mm) Kg 0.629921 16 9073.303 0.551181 14 5954.355 0.472441 12 5103.733 0.393701 10 4253.111 0.314961 8 3402.489 0.23622 6 2551.866 0.23622 6 2551.866 0.23622 6 2551.866 0.23622 6 5621.503 Σ 41064.09 Kg = 90505.26 pd Roof plate weight=12283 kg = 27072.7 pd Roof structure weight=4482 kg = 9878 pd

REMARKS:

DESIGNED BY

CHECKED BY

APPROVED BY

Steel Welded Tank Dia.:15.75 m 18.00 m Height

73.4 kg/m2 → Wind load on tank wind velocity =48m/s=108mile h → wind force 0-16=860 kPa=87.6 kg/m2 wind force 16-17.2=720 kPa=73.4 kg/m2 according to API 650 3.11.1 →

17.2 16

87.6 kg/m2 → 8 87.6 kg/m2 → 0

Load between 0-16 : F1=87.6x16x18= 25229 kg

Load between 16-17.2 F3=73.4xArea=73.4x1.2x18x0.5=792.7 kg Overturning moment due to wind load: M=F1x8+F3x(16.4)= 214832 Kg.m Overturning stability (3.11) W= shell weight to resist uplift less corrosion+dead weight supported by shell minus uplift from internal pressure W= 20210+ 27072.7 +9878-555x(18x18/4xπ)=42851 kg Stability Moment = 2/3x(WD/2)=257106 kg.m > M So, It does not need Anchor Bolts. Seismic Design of the Storage Tank:

(APPENDIX E)

M =Zx I (C1xWsxXs + C1xWrxHt + C1xW1xX1+C2xW2xX2) Z : seismic zone factor=0.2 I=1.0 E3.1 C1=0.60 (API 650 - E3.3) D/H=18/16=1.1→ K=0.58 (Figure E-4) T(natural period of the first sloshing mode, in second) =K√D =0.58x√59 =4.45