API-650 design procedure example

DESCRIPTION

PAGE

1

DESIGN DATA

3

2

CALCULATIONS FOR MINIMUM SHELL THICKNESS

4

3

BOTTOM PLATE DESIGN

5

4

INTERMEDIATE WIND GIRDER

4.1 AS PER API 650 SEC. 3.9.7

6

5

SUPPORTED CONICAL ROOF

5.1 DESIGN OF ROOF PLATE

7

5.2 DESIGN OF ROOF PLATE WITH STIFFENING

7

5.3 DESIGN OF COMPRESSION RING

8

5.4 DESIGN OF ROOF RAFTERS

10

6

COMPRESSION AREA AT ROOF TO SHELL JOINT

6.1 DESIGN OF COMPRESSION AREA AS PER API 650 App. F

11

7

STABILITY OF TANK AGAINST WIND LOADS

7.1)RESISTANCE TO SLIDING

13

8

FOUNDATION LOADING DATA

14

9

VENTING CALCULATIONS

16

10

NOZZLE FLEXIBILITY ANALYSIS AS PER APPENDIX P

19

11

SHELL TO ROOF RAFTER JOINT STRESS ANALYSIS

20

Design Code : API 650, 10th Edition, Add.4 2005, Appendix F Client's Specs. : 32-SAMSS-005, BD-407062 Rev.00C

Fluid : FIRE / UTILITY / WASH WATER TANK

Material : SA-516 Gr 70.

Density of contents = 1004.9

Specific gravity of contents G = 1.0049

Material's yield strength = 260 MPa API 650 Table-3.2

Design Temperature T = 71

Internal Pressure Pi = 0.747 Kpa = 3.0 inch of water

External Pressure Pe = 0.245 Kpa = 1.0 inch of water

High Liquid Level = 8.560 m

Design Liquid Level = 9.000 m

Allowable Design Stress at Design Temp. = 173.00 MPa API 650 Table-3.2 Allowable Test Stress for Hydrostatic Test Condition St = 195.00 MPa API 650 Table-3.2

Corrosion allowance

Bottom = 3.20 mm

Shell = 3.20 mm

Roof = 3.20 mm

Roof Supporting Structure = 3.20 mm

Slope of Tank Roof  = 9.46 0 1 : 6

Outside dia. of tank = 13.516 m

Inside dia of tank = 13.500 m

Nominal dia. of tank D = 13.508 m = 44.32 ft

Height of Shell H = 9.000 m

Weight of roof attachments

(platform, handrail, nozzles, etc.) Wr = 30.00 KN Weight of attachments (pipe clips, nozzles, etc.) Ws = 5.00 KN

Weight of curb Angle Wc = 6.85 KN

Design Wind Velocity V = 154 Km/hr

Yield Strength of Steel Structure Fy = 250 M Pa = 36.259 Ksi

Live Load on roof = 1.2 Kpa API 650 Sec. 3.2.1d

1) DESIGN DATA

D_{L kg./m}3 d_y o_C H_l H_L Sd D_o D_i L_r

Calculations of Shell Thicknesses by Section 3

The minimum thickness of shell plate as per section 3.6.3.2, shall be computed using following formula;

Where,

G = Specific Gravity of fluid to be stored = 1.0049

D = Nominal dia. of tank = 13.508 m

= 9.00 m

CA = Corrosion allowance on shell = 3.20 mm 1st Shell Course

Width of 1st course = 2.500 m

Design height for 1st shell course = 9.076 m

(Including Equivalent head due to internal pressure)

Required Shell Thickness = 6.57 mm

Required Shell Thickness = 3.36 mm

Shell thickness provided = 8.00 mm 2nd Shell Course

Width of 2nd course = 2.500 m

Design height for 2nd shell course = 6.576 m

Required Shell Thickness = 5.61 mm

Required Shell Thickness = 2.13 mm

Shell thickness provided = 8.00 mm

(As per Tank General Note 3 of Data Sheet) 3rd Shell Course

Width of 3rd course = 1.880 m

Design height for 3rd shell course = 4.08 m

Required Shell Thickness = 4.65 mm

Required Shell Thickness = 1.28 mm

Shell thickness provided = 6.00 mm 4th Shell Course

Width of 4th course = 2.120 m Including Curb Angle Design height for 4th. shell course = 2.196 m

Required Shell Thickness = 3.93 mm

Required Shell Thickness = 0.64 mm

Shell thickness provided = 6.00 mm

Shell Table -1 Shell Course # 1 2 3 4 Shell width (m) 2.500 2.500 1.880 2.000 Shell Thickness (mm) 8.00 8.00 6.00 6.00 Corroded Shell Thk.(mm) 4.80 4.80 2.80 2.80 Shell Weight (KN) 65.36 65.36 36.86 39.22

Shell Weight (KN)Corroded 39.22 39.22 17.20 18.30

Total Shell Weight (KN) = 206.80 KN

Total Shell Wt.(KN) (Corroded) = 113.93 KN

Total weight of corroded shell + Shell attachments, = 120.78 KN

2) CALCULATIONS FOR MIN. SHELL THICKNESS

Design Shell Thickness t_d = 4.9D (H _L1 - 0.3)G + CA S_d

Hydrostatic Test Thickness t_t = 4.9D (H _L1 - 0.3) S_t

H_L = Design liquid level for course under consideration

W₁ H_L1 t_d t_t t₁ W₂ H_L2 t_d t_t t₂ W₃ H_L3 t_d t_t t₃ W₄ H_L4 t_d t_t t₄ W'_ST

As per API 650 Sec. 3.4.1

All bottom plates shall have minimum nominal thickness of 6mm, exclusive of any corrosion allowance. Required Bottom Plate Thickness = 6+ CA mm

= 9.20 mm

Used bottom plate thickness = 10.00 mm

Weight of bottom Plate = 11430.3 kg = 112.13 KN Weight of bottom Plate ( Corroded ) = 7772.6 kg = 76.25 KN

(API 650 Sec. 3.5)

Hydrostatic test stress for first shell course =

= 119.97 M Pa < 172 M Pa OK If hydrostatic test stress for first course is less than 172 Mpa,

lap welded bottom plates may be used in lieu of butt-welded annular bottom plates.

Thickness of annular bottom plate = 10.00 mm

Max. design liquid level = 9.08 m

Width of annular bottom plate =

(between shell ID & lap of bottom plate with annular plate)

Required width of annular bottom plate = 711.91 mm

Width of annular bottom plate provided = 800.0 mm

3) BOTTOM PLATE DESIGN

t_b t_b

3.1) ANNULAR PLATE DESIGN

S_h (4.9D (H₁ - 0.3)/t_sc) t_b H_L1 W_ap 215 x t_b / (H_L1 x G)1/2 W_ap W_act

The maximum height of the unstiffened shell = API 650 Sec.3.9.7.1 Where,

t = As ordered thickness of top shell course = 6.00 mm t = As Per Article 3.9.7.1 of 32-SAMSS-005 = 2.80 mm D = Nominal tank diameter = 13.508 m

V = Design wind speed = 154.00 Km/hr

The maximum height of the unstiffened shell = 3.81 m

Transposed width of each shell course = API 650 Sec.3.9.7.2 Where,

W = Actual width of each shell course (mm)

= 6.00 mm 1st Shell Course

As ordered thickness of 1st shell course = 8.00 mm Actual width of 1st shell course = 2500 mm Transposed width of 1st shell course = 1218 mm 2nd Shell Course

As ordered thickness of 2nd shell course = 8.00 mm Actual width of 2nd shell course = 2500 mm Transposed width of 2nd shell course = 1218 mm 3rd Shell Course

As ordered thickness of 3rd shell course = 6.00 mm Actual width of 3rd shell course = 1880 mm Transposed width of 3rd shell course = 1880 mm 4th Shell Course

As ordered thickness of 4th shell course = 6.00 mm Actual width of 4th shell course = 2120 mm Transposed width of 4th shell course = 2120 mm Height of transformed Shell =

= 6436 mm = 6.436 m

As Htr > H1 Intermediate Wind Girder is Required Intermediate Wind Girder

The required minimum section modulus of an intermediate wind girder shall be calculated as follows.

API 650 Sec.3.9.7.6 17

angle of the shell = 3.218 m D = Nominal Tank diameter = 13.508 m

22.69

From Table 3-20 we provide one angle of 102*76*6 as intermediate wind girder as per fig. 3-20 detail c

Section modulus provided = 50.2

4) INTERMEDIATE WIND GIRDER

4.1) As per API 650 Sec. 3.9.7

H_{1 9.47 t (t / D)}3/2 _{x (190/V)}2

H₁

Height of transformed Shell

W_tr W x (t_uniform/t_actual)5/2

t_uniform = As ordered thickness of top shell course

t_actual = As ordered thickness of shell course for which transposed width is being calculated (mm) t₁ W₁ W_tr1 t₂ W₂ W_tr2 t₃ W₃ W_tr3 t₄ W₄ W_tr4 H_tr W_tr1 + W_tr2 + W_tr3 + W_tr4 Z_req. = D 2 _H 1 x (V/190)2

Where: Z = Required minimum section modulus of intermediate wind girder. (cm3₎ H₁ = Vertical distance (m) between the intermediate wind girder and the top

Z_req. = _cm3 Z_pro.= _cm3

(Including shell participating width & corroded thickness of 2.8mm)

5.1) Supported Conical Roof

Minimum roof plate thickness

= D x √Tr/2.2 API 650 Sec.3.10.5.1 Where, Tr = Greater of load combinations (e)(1) and (e)(2) as per App. R

Combination i, API 650 App. R (e)(1)

Combination ii, API 650 App. R (e)(2)

Where, Dead Load of the roof, = 0.981 kPa Live Load on the roof, Lr = 1.200 kPa External Pressure, Pe = 0.245 kPa Snow Load, S = 0.000 kPa = 2.279 kPa = 1.706 kPa

Tr = 2.279 kPa API 650 Sec. 3.10.5

= 17.43 mm ≥ 5 mm

= 20.63 mm

As per API Sec. 3.10.5.1 the Maximum thickness for self supported roof is 12.5mm (excluding corrosion allowance) but due to high value of calculated roof thickness, it is proposed to provide supported roof.

Used thickness = 10.00 mm

= 10.00 mm (Including Corrosion Allowance) Roof developed radius

=

6.85 m

Roof developed Area

=

147.5

Weight of Roof = 114.72 KN Weight of Roof (corroded) = 77.22 KN

Roof is designed as a supported cone roof. The system of rafters is provided to support the roof plate. The rafters are supported at tank shell and load is transferred to tank periphery.

Maximum Spacing of Rafters at Outer Ring = 0.6 * π

= 1.88 m API 650 3.10.4.4 Maximum No. of Rafters Required N = π x D/0.6 X π

= 22.51

( Brownell & Young - 4.3b)

Roof plate shall be designed as continuous beam with uniform load comprising of roof live load and self weight of roof plate. The maximum unsupported span of roof plate is equal to the spacing of stiffeners at tank outer dia.

24.00

Roof Plate Span l

=

1.77 m = 69.7 inch (Maximum spacing of Rafters at tank outer dia) Roof plate thickness tr

=

6.80 mm = 0.26772 inch (corroded plate thickness)

Assumed Plate width b

=

1 inch

Design Live Load Lr

=

1.20

6.851

147

=

0.78

Design load for roof plate shall be comprising of roof live load and the total dead load acting on the roof.

=

1.98 = 0.29 psi

Assuming width of roof plate 1 inch and calculating the bending moment for strip if roof plate 1 inch wide. Roof Plate Span l

=

69.7 inch

=

0.29 lbs/inch

Bending Moment At Mid Span Mc

=

=

58.035 lbs inch 24

Bending Moment At Supports Ms

=

=

116.07 lbs inch 12

Section modulus of Plate Zp

=

=

0.012 Allowable Bending Stress 0.6 x Fy

=

22625.9 psi ( As per API 650)

=

270.3 lbs inch

Mallow>Ms Thickness Is Ok

Therefore Plate Thickness Provided

=

6.80

+

CA

=

10.00 mm (Including Corrosion Allowance)

5) Design of Roof Plate

t_R 4.8 Sin P₁ = D_L + (L_r or S) + 0.4 P_e P₂ = D_L + P_e + 0.4 (L_r or S) D_L P₁ P₂ (Max. of P₁ & P₂) t_R t_R + C.A.

Roof Plate Thickness t_prov

R_r

A_{r m}2

5.2) Design of Roof Plate and Stiffening Member

Number of Rafters N₂ =

KN/m2 Self Wt. of roof plate W_{r KN/m}2 Roof Plate Design Load w_p = Lr + W_{r KN/m}2

Design load/ length w = w_p x b

wl 2 wl 2

b tr2_{/6 in}3

F_b =

1.2

1.04 (including weight of rafters & accessories) 2.24 (udl due to roof plate and live load) 6.75 m

Radius of central compression ring 0.80 m

Span of Rafter Ls = 6.03 m

Self weight of Rafter = 25.30

Total weight of Rafter = 3662.6 Kg = 35.93 KN

= 2444.8 Kg = 23.98 KN

Total weight of Rafter/area = 0.24 Weight of Rafter gr = 0.248

Weight of Central Ring Wr = 2.76 KN

Number of rafter 24.00

Height of Roof at center h = 1.12 m

Radius of tank - radius of compression ring = 5.95 m

=

= 3.959

=

= 0.469

Calculation of load transferred at joint of stiffener and central ring Weight of Central Ring ,Wr per stiffener

= Wr = 0.115 KN

5.3) Design of Compression Ring

Fig- 2 : Central Compression Ring Loading Diagram

Live Load on roof L_r = _KN/m2

Load of roof plate D_r = _KN/m2

g = L_r + D_r = _KN/m2

Radius of tank R =

R₂ =

Kg/m Total weight of Rafter corroded

KN/m2 KN/m N_{2 =} R₁ = g₁ 2Rg KN/m N₂ g₂ 2R ₂g _KN/m N₂ W_a = P₁ + P₂ P₁ N  

= 0.38 KN Load transferred to central ring by rafters,P₂ = g₂ x R₂

0.49 KN

= 0.72

= 3.49 Considering the equilibrium and taking Moments about point A.

h 32.19 KN

32.19 KN = 7.24 Kips 24

0.8 m = 2.624 ft Moment transferred to ring, M =

M = 0.41 Kip ft = 0.562 KN m

27 Kips = 122.25 KN

PROPERTIES OF COMPRESSION RING (Corroded)

b1 = 200 1360 4624

h1 = 6.8 3400 850000

b2 = 6.8 1496 164560

h2 = 500 Location of Centroid ( See Fig)

b3 = 6.8 162.91 mm h3 = 220 A Moment of Inertia 3.4 250 12 12 12 110 I = 141451394.829 A = 6256 0.00626 Section Modulus = 419628.8

=

0.0004196288 1340.28 Z

Allowable Bending Stress Fb = 0.6 Fy = 150000 19541.63 A

Allowable Compression Stress Fc = 0.5 Fy = 125000

0.17 Fb Fc W_a = P₁ + P₂ = g₀ = g_r + g_{2 KN/m} g₃ = g₁ - g_{2 KN/m} H_a = W _a x R ₁ +(g ₀ x R ₁) R ₁/2 + g ₃ (R ₁/2) ( R ₁/3) H_a =

Radial Load transferred to ring through stiffeners, H_a = Number of Stiffeners Supported on central Ring, N₂ = Radius of central compression ring, R₂ =

Ha R ₂ ( cot 180 - N ₂ ) = 2 N₂ 

Thrust T = Ha Cot 180 = 2 N₂

Fig -3 : Central Compression Ring

A₁= b₁h₁ = _mm2 A₁y₁ = _mm2 A₂= b₂h₂ = _mm2 A 2y2 = mm2 A₃= b₃h₃ = _mm2 A 3y3 = mm2 C = A ₁y ₁ + A ₂y ₂ +A ₃y ₃ = y₁= I = b ₁h ₁3 _{+ A}

1 (C-y1)2 +b 2 h 23 +A2(C-y2)2 + b 3 h 33 + A3 (C-y3)2 y₂= y₃= _mm4 mm2 _{= m}2 Z = I / (h₂ - C) = _mm3 _m3 f_b = M = _KN/m2 KN/m2 fc = T = KN/m2 KN/m2 f _b + _{fc =}

Number of internal stiffeners N = 24

Section used = (UPN 200)

Corroded properties of Rafter

h = 197 mm bf = 72 mm tf = 8.3 mm tw = 5.3 mm Area = 2151.32 I = 1.3E+07

Span of stiffener, Ls = 6.03 m = 237.48 inch

Wt = 16.9 Kg/m (Wt of corroded section)

Total area of Section A = 2151.32

Location od centroid from top yc = 98.50 Total moment of inertia I = 13239449.40427

Section modulus Z = I/yc = 134410.65 8.20

From fig - 2, the moment at distance x from compression ring is obtained as follows. where, and gx = g3 X R1 hx = 0.189028 X gx = 0.5865 X Ha = 32.19 KN Wa = 0.49 KN 32.64 KN Mx = 5.59 X - 0.359 0.0978 Therefore Mx = d 5.59 X - 0.717 0.293 dx d = 5.59 - 0.717 X - 0.293 = 0 for M=M max dx

Solving above quadratic equation. a = 0.293 b = 0.717 c = -5.595 X = 3.31 m and -5.8 m 25.447 M max = 11.04 KN-m = 97664.6 lbs-inch Allowable Stresses

a) Bending stress shall be

Bending stress shall be greater of the Following

= 19994.77 psi = 6034.79 psi Fb=12000000Af/(ld)

Therefore Allowable Bending Stress Fb = 19994.77 psi b) Compression

Fc = 0.5 Fy = 18129.71 psi Induced Stresses

fb =Mmax/Z = 11907.1 psi

fc = Na/As = 2198.2 psi

Ratio of stresses induced to allowable stresses

0.717

Fb Fc

As fb/Fb+fc/Fc<1 Ok 5.4) Design of Roof Rafters

mm2 mm4 mm2 mm mm4 mm3 _{= in}3 Mx = Ha hx -Wa X-go/2 X2 _{- gx/6 X}2 hx = h X R₁ Na=Ha/Cos = X 2 _{- X}3 X 2 _{- X}3 X 2 Fb=20000-0.571*(l/r)2 fb + fc =

Minimum required curb angle

Used Curb Angle As per Fig. F2 Detail d = 120 x 120 x 10 API 650 Sec. 3.1.5.9

Curb Angle Area = 1218 (Corroded Area)

Length of normal to roof from tank C.L. =

= 41,069 mm

Inside radius of tank, = 6,750 mm

Max. width of participating roof = Ref: API 650 Fig F-2

Thickness of roof plate (corroded) = 6.80 mm = 158.54 mm Max. width of participating shell =

Thickness of shell plate (corroded) = 2.80 mm = 82.49 mm Participating area of roof (corroded) =

1078 Participating area of shell (corroded) =

= 231

Total Area Provided =

= 2296

= API 650 App.F.5.1

= 295.30

Since, 2296 > 295 Aprov. >Amin, Therefore used Curb Angle is satisfactory

Uplift on Tank as per F.1.2

Corroded Roof Thickness = 6.80 mm

D = 13.508 m

Area of tank =

= 143 Internal design pressure of tank = 0.747 kPa Total upward lifting force acting on roof =

= 107 kN

Weight of roof (corroded) = 77.22 kN

107 > 77.22 Weight of shell, roof and attached framing = 224.75 kN

107 < 224.75

F.2 through F.5 are applicable

Internal design pressure is, P = API 650 F.4

= 2.85 kPa Weight of shell and attached framing = 120.78 kN

Max. design pressure, limited by uplift at base of shell is; API 650 F.4.0 =

= 0.841 kPa But, internal design pressure of tank is = 0.747 kPa

0.747 <= 0.841 Condition Satisified - Anchorage is not Required

Min. Required Compression Area is Greater of the following As Per F.5.1 =

= 295.30 =

= 973.7

Since, 1218 > 973.7

6) Compression Ring at Shell to Roof Joint

A_c mm2 R₂ R_c / sin  R₂ R_c w_h 0.3 x (R₂ x t_h) t_h w_h w_c 0.6 x (R_c x t_s) t_c w_c A_h w_h x t_h mm2 A_s w_c x t_c mm2 A_prov. A_h + A_c A_prov. mm2

Minimum required participating area, A_min. D2 _(P

i-0.08th) / (1.1xTan)

A_min mm2

6.1) Tank Design As Per Appendix F

t_R Nominal dia. of tank (D_i + Shell thick)

A_{t } x R2 m2 P_i F_R P_i x A_t W_R D'_L (1.1 x A x tanθ) / D2 _{+ 0.08 x t} R W'_ST = D_LS P_max 0.00127 x D_LS / D2 _{+ 0.08 x t} R - 0.00425 x Mw / D3 P_i A_min.1 D2 _{x (P} i-0.08th)/1.1(tan ) mm2 A_min.2 D2 _{x [0.4P} i-0.08th+0.72(V/120)2]/1.1(tan ) mm2

7)Stability of Tank Against Wind Load

( Ref: ASCE-7)

Wind velocity V = 154.0 Km/hr = 42.78 m/s

height of tank including roof height = 10.125 m = 33.2091 ft.

effective wind gust factor G = 0.85

force coefficient Cf = 0.50

wind directionally factor Kd = 0.95

Velocity Pressure Exposure Co-Eff. Kz = 0.95

Topo Graphic Factor Kzt = 1.0

Importance Factor I = 1.15

Design Wind Pressure qz =

1.164

Design Wind Load = qz x Do x G x Cf x Ht

67.711 KN = 2 342.78 KN-m = 252746.5 ft-lbs Resisting Moment Resisting Moment = 3 2

Ws' = total weight of tank shell + Curb Angle = = 120.785 KN

Wr' = total weight of tank roof = 101.203 KN (Including Rafters) Mr = 517.567 KN-m

As Mr > Mw Anchorage is Not Required

7.1)Resistance To Sliding ( Ref: API 650 3.11.4)

The wind load\ pressure on projected area of cylindrical surfaces = 0.86 18.0 psf This pressure is for wind velocity of 100 mph (160 Km/hr) For all other wind velocities

= 13.516 m Design Wind Velocity V = 154 Km/hr

= 0.926 (Vf=Velocity Factor) = 0.86

Wind Pressure on vertical conical surfaces = 0.72 Projected area of roof = 7.601 Projected area of shell = 121.64

= Vf(Wind Pressure on Roof X Projected Area of Roof + Wind Pressure on Shell X Projected Area of Shell)

= 101.985 KN

= Maximum of 40% of Weight of Tank

= 109.702 KN

Ffriction>Fwind No Anchorage Is Required To Resist Sliding

H_t

0.613 x Kz x Kzt x Kd x V2 x _I/1000 KN/m2

P₁

Overturning Wind Moment Mw P1 x Ht

Mr = 2 D (Ws' + Wr'-Uplift due to Design Pressure )

KN/m2 ₌ the pressure shall be adjusted in proportion of ratio (V/160)2

O.D of tank = D₀ (Ve/160)2

Wind Pressure on vertical plane surfaces KN/m2 KN/m2 m2 m2 F_wind

The self weight of roof and live load will be transferred to tank shell

Live load transferred to foundation

1.2

Area of Roof, Ar = 147.46

176.95 KN

Circumference of Tank C = 42.5 m

4.2 KN/m

Dead load transferred to foundation

Self Weight of Roof Wr = 153.41 KN (Including Rafter & Compression Ring) Self Weight of Shell Ws = 206.80 KN

Self Weight of shell Attachments Wa = 15.00 KN (Including Curb Angle & Inter. Wind Girder) Total Dead Load acting on shell WD = 375.20 KN (Including Platform Weight)

Dead Load Transferred to Foundation Wd = WD / C 8.84 KN/m

Operating & Hydrostatic Test Loads

Self Weight of Tank = 487.34 KN

Weight of Fluid in Tank at Operating Conditions = Wf = 12715 KN Weight of Water in Tank at Hydrotest Conditions = Ww = 12638 KN

Uniform Load at Operating Condition = Self Wt. + Fluid 92.12 Uniform Load at Hydrotest Condition = Self Wt. + Water 91.59

Wind Load Transferred to Foundation

Base Shear due to wind load, Fw = 70.3 KN

Reaction due to wind load, Rw = 0.6 KN/m

Moment due to wind load, Mw = 342.8 KN-m

8) Foundation Loading Data

Live Load on roof, L_r = _KN/m2

m2 Total Live Load, W_L = L_r x A_r

 x D

Live Load transferred to Foundation w_L = W_L / C

W_o = _KN/m2 W_h = _KN/m2

Summary of Foundation Loading Data

Dead load, shell, roof & ext. structure loads 8.84 KN/m

Live Load 4.17 KN/m

Uniform load, operating condition 92.12

Uniform load, hydrotest load 91.59

Base shear due to wind 70.32 KN

Reaction due to wind 0.60 KN/m

Moment due to wind load 342.78 KN-m

Note: 15% to 20% Variation will be consider while designing the Foundation.

Summary of Tank Major Parts Thickness and Weight

Item Plate Thickness (mm) Weight (Kgs) Shell Plate 8.00_6.00 13,325_7,755

Bottom Plate 10.00 11,430

Roof Plate 10.00 11,694

Roof Rafter & Compression Ring - 3,944

Tank Capacity Calculations: As per API 650 App. L

I. 4 Where: Di = 13.500 m H = 9.000 m 1288 = 45,459 II. 4 8.560 m LL = 6.965 m 228.31 = 8,056 D_L = L_L = W_o = _KN/m2 W_h= _KN/m2 F_w = R_w = M_w=

Nominal Capacity, Q_max.

Q_max. = _x Di2 _{x H}

m3

Q_max. = _m3 _ft3

Net Working Capacity, Q_net

Q_net. = xDi 2 _{x (H}

1-LL) _m3 Where: H₁ =

Bolt Connection Stress Analysis

=

2.24

Mpa

( Refer to 5.3. Design of Compression Ring)

Radial Load transferred to the end of the rafter

Hr =

Where;

D = Tank Diameter =

13.5 m

Number of Rafter =

24

Ls = Length of Rafter =

6.03 m

Hr =

2.22

KN/m

By applying this load on the rafter

Max. Shear Force Induce,P =

6.12 KN

(from STAAD result)

Now, calculating the Shear Stress for 3/4"-10 x 1- 1/2" Hex. Head Bolt, A193-B7.

F =

P/A

Where;

A = Bolt Shear Area =

A =

0.334

215.4834

But there are two bolts in this connection, therefore, A =

430.9669

Induced Shear Stress on Bolt

14.20

Mpa

As per ASTM 193

Min. Tensile Strength, Fu =

485

Mpa

(Ref. ASTM A193 Table 3)

Allowable Stress;

Shear Stress

( Ref. Table I-D AISC Allowable Stress Design, 9th Edition)

Fv = 0.17 Fu

Fv =

82.45

Mpa

> Induced Stress

Ultimate Dead Load on the roof including Live Load + Self Weight of Roof + Weight of Accessories, g

g

_u

=

L

_r

+ D

_r

g

_u

x



D

2

4Ls*N

₂

N

₂

=

0.7854 ( D-(0.9743/n))

2

in

2

₌

_mm

2

mm

2

F =

Allowable Stress of Bolt is greater than the required maximum stress for the connection.

Therefore, the provided Bolt is SAFE and ADEQUATE.

( Refer to 5.3. Design of Compression Ring)

( Ref. Table I-D AISC Allowable Stress Design, 9th Edition)

Ultimate Dead Load on the roof including Live Load + Self Weight of Roof + Weight of Accessories, g

_u