Storage Tank

APPENDIX B (DESIGN CALCULATION)

STORAGE TANK DESIGN CALCULATION - API 650 1 .0

1 .1 .1

1 .2

1 .3

1 .4

DESI DESIGN GN CODE CODE & SPEC SPECIIFICA FICAT TION ION DESIGN CODE

: API 650 11th Edition

TANK Item number Roof ( Open/Close ) Type of roof ( Cone-roof / Dome-roof / Flat-roof / NA )

: 7061T-3901 : Close : Floating Roof

GEOMETRIC DATA Inside diameter , Di ( corroded ) (@ 39,000 mm ) Nominal diameter, Dn ( new ) ( based on 1st shell course ) Nominal diameter, Dc ( corroded ) ( based on 1st shell course ) Tank height (tan/tan), H Specific gravity of operating liquid , S.G. (Actual) Specific gravity of operating liquid , S.G. (Design) Nominal capacity , V Maximum design liquid level, HL

= = = = = = = =

PRESSURE & TEMPERATURE Design pressure : Upper , Pu : Lower , Pl Design temperature : Upper , Tu : Lower , Tl

39,006 mm 39,028 mm mm 39,031 mm 20,700 mm 0.790 1.00 24736 m³ 20,700 mm

(Atmospheric) = = = =

0.00 0.00 70 -17

MAT MATERIA ERIAL L & MEC MECHA HAN NICAL ICAL PROP PROPE ERTI RTIES Component

PLATE She Shell Pla Plate

( Ma Mat'l t'l Cod Codee # 1 ) (bot) ot) ( Mat'l Code # 2 ) (top)

Annular Plate Bottom Plate Roof Plate STRUCTURE MEMBERS Roof structure (rafter,bracing,etc ) Top Curb Angle Intermediate Wind Girder

Material

Tensile Stress St(N/mm²)

Yield Stress Sy(N/mm²)

Corrosion Allowance c.a.(mm)

A 516 GR. 65N A 516 GR. 65N A 516 GR. 65N A 516 GR. 65N A 516 GR. 65N

448.00 448.00 448.00 448.00 448.00

241.00 241.00 241.00 241.00 241.00

3.000 3.000 3.000 3.000 3.000

A 516 GR. 65N A 516 GR. 65N A 516 GR. 65N

448.00 448.00 448.00

241.00 241.00 241.00

3.00 3.00 3.00

mbarg mbarg Vac °C °C

STORAGE TANK DESIGN CALCULATION - API 650 1 .0

1 .1 .1

1 .2

1 .3

1 .4

DESI DESIGN GN CODE CODE & SPEC SPECIIFICA FICAT TION ION DESIGN CODE

: API 650 11th Edition

TANK Item number Roof ( Open/Close ) Type of roof ( Cone-roof / Dome-roof / Flat-roof / NA )

: 7061T-3901 : Close : Floating Roof

GEOMETRIC DATA Inside diameter , Di ( corroded ) (@ 39,000 mm ) Nominal diameter, Dn ( new ) ( based on 1st shell course ) Nominal diameter, Dc ( corroded ) ( based on 1st shell course ) Tank height (tan/tan), H Specific gravity of operating liquid , S.G. (Actual) Specific gravity of operating liquid , S.G. (Design) Nominal capacity , V Maximum design liquid level, HL

= = = = = = = =

PRESSURE & TEMPERATURE Design pressure : Upper , Pu : Lower , Pl Design temperature : Upper , Tu : Lower , Tl

39,006 mm 39,028 mm mm 39,031 mm 20,700 mm 0.790 1.00 24736 m³ 20,700 mm

(Atmospheric) = = = =

0.00 0.00 70 -17

MAT MATERIA ERIAL L & MEC MECHA HAN NICAL ICAL PROP PROPE ERTI RTIES Component

PLATE She Shell Pla Plate

( Ma Mat'l t'l Cod Codee # 1 ) (bot) ot) ( Mat'l Code # 2 ) (top)

Annular Plate Bottom Plate Roof Plate STRUCTURE MEMBERS Roof structure (rafter,bracing,etc ) Top Curb Angle Intermediate Wind Girder

Material

Tensile Stress St(N/mm²)

Yield Stress Sy(N/mm²)

Corrosion Allowance c.a.(mm)

A 516 GR. 65N A 516 GR. 65N A 516 GR. 65N A 516 GR. 65N A 516 GR. 65N

448.00 448.00 448.00 448.00 448.00

241.00 241.00 241.00 241.00 241.00

3.000 3.000 3.000 3.000 3.000

A 516 GR. 65N A 516 GR. 65N A 516 GR. 65N

448.00 448.00 448.00

241.00 241.00 241.00

3.00 3.00 3.00

mbarg mbarg Vac °C °C

SHELL THICKNESS CALCULATION BY ONE-FOOT METHOD 2 .0 2 .1

SHELL DESIGN GEOMETRIC DATA Plate size used Shell plate min. width as per

2 .2

2,440 mm 1,500 mm

MAT MATERIA ERIAL L & MEC MECHA HAN NICAL ICAL PROP PROPE ERTI RTIES

No

Material used

Specified Specified Yield stress Max. allow min. te tensile min. yield reduction fac design stress stress ( App. M ) stress St (N/mm²) Sy (Nmm²) k Sd (N/mm²)

Max. allow hydro.test stress St (N/mm²)

Corrosion allowance c.a (mm)

1 2 3 4 5 6

A 516 GR. 65N A 516 GR. 65N A 516 GR. 65N A 516 GR. 65N A 516 GR. 65N A 516 GR. 65N

448.00 448.00 448.00 448.00 448.00 448.00

241.00 241.00 241.00 241.00 241.00 241.00

1.000 1.000 1.000 1.000 1.000 1.000

160.67 160.67 160.67 160.67 160.67 160.67

180.75 180.75 180.75 180.75 180.75 180.75

3.00 3.00 3.00 3.00 3.00 3.00

7

A 516 GR. 65N

448.00

241.00

1.000

160.67

180.75

3.00

8 A 516 GR. 65N 9 A 516 GR. 65N 10 -

448.00 448.00 -

241.00 241.00 -

1.000 1.000 -

160.67 160.67 -

180.75 180.75 -

3.00 3.00 -

2 .3

SPEC SPECIIFIE FIED MIN MINIMU IMUM SHEL SHELL L THI THICK CKN NESS ESS Specification Minimum thickness as per API 650 cl 5.6.1.1 Minimum thickness as per PTS 34.51.01.31

2 .4

: API 650 11th Edition = 8.00 mm = 11.00 mm

SHELL SHELL THICKN THICKNESS ESS CALCUL CALCULATI ATION ON BY ONE-FO ONE-FOOT OT METHOD METHOD ( CLAU CLAUSE SE 5.6.3. 5.6.3.1 1) SI METRIC UNIT :Design shell thickness, ( in mm ) 4.9Dc ( [H+Hi] - 0.3 ).G td = + c.a Sd Hydrostatic test shell thickness , ( in mm ) 4.9Dn ( H - 0.3 ) tt = St Gravitational force = 9.81 m/s

2 .5

t.min = Min. of t.des t.design, ign, t.hyd t.hydo o& min. thickness as per PTS. tsc = Thi Thickn cknes es select selected ed & used used

CALCULATION & RESULTS

No. Mat'l Code No. 1 2 3 4 5 6 7 8 9

: :

PTS 34.51.01.31 clause 6.3

1 1 1 1 1 1 1 1 1

Material

Width (mm)

Height (mm)

t.design (mm)

A 516 GR. 65N A 516 GR. 65N A 516 GR. 65N A 516 GR. 65N A 516 GR. 65N A 516 GR. 65N A 516 GR. 65N A 516 GR. 65N A 516 GR. 65N

2,440 2,440 2,440 2,440 2,440 2,440 2,020 2,020 2,020

20,700 18,260 15,820 13,380 10,940 8,500 6,060 4,040 2,020

27.30 24.40 21.49 18.58 15.67 12.77 9.86 7.45 5.04

t.hydro. (mm)

t.min (mm)

tsc. (mm)

Result

21.60 19.02 16.43 13.85 11.26 8.68 6.10 3.96 1.82

27.30 24.40 21.49 18.58 15.67 12.77 11.00 11.00 11.00

28.00 25.00 22.00 19.00 16.00 13.00 11.00 11.00 11.00

O.K. O.K. O.K. O.K. O.K. O.K. O.K. O.K. O.K.

2 .6

MAXIMUM ALLOWABLE STRESS

No.

Height (mm)

t.min (mm)

tsc. (mm)

H' (mm)

H' max (mm)

∆H (mm)

P'max N/m²

Pmax N/m²

1 2 3 4 5 6 7 8 9

20,700 18,260 15,820 13,380 10,940 8,500 6,060 4,040 2,020

27.30 24.40 21.49 18.58 15.67 12.77 11.00 11.00 11.00

28.00 25.00 22.00 19.00 16.00 13.00 11.00 11.00 11.00

20,700 18,260 15,820 13,380 10,940 8,500 6,060 4,040 2,020

21,306.77 18,786.53 16,266.30 13,746.06 11,225.82 8,705.59 7,025.43 7,025.43 7,025.43

606.77 526.53 446.30 366.06 285.82 205.59 965.43 2985.43 5005.43

5,952.41 5,165.29 4,378.18 3,591.06 2,803.94 2,016.82 9,470.87 29,287.07 49,103.27

5,952.41 5,165.29 4,378.18 3,591.06 2,803.94 2,016.82 2,016.82 9,470.87 29,287.07

H' = H' max = P'max = Pmax =

Effective liquid head at design pressure Max. liquid head for tsc. Max. allowable stres s for tsc. Max. allowable stres s at shell course.

BOTTOM & ANNULAR PLATE DESIGN 3 .0

BOTTOM PLATE & ANNULAR PLATE DESIGN Annular plate used ? ( yes/no ) BOTTOM PLATE (i) Minimum thickness as per Minimum thickness required Therefore, use thickness of (ii) (iii) (iv) (v)

(@

: yes

API 650 Clause 5.4.1 3.00 mm c.a ) 9.00 mm (tb) is

ANNULAR PLATE (i) Nominal thickness of 1st shell course, tsc1 Hydro. test stress in 1st shell course, 4.9Dn(H-0.3) St = tsc1 where Dn = Nominal diameter, Dn ( new ) ( based on 1st shell course ) H = Design liquid level tsc1 = Nominal thickness of 1st shell course

3.00 16.00

mm c.a. ) mm (ta) is

(ii) Min. shell-to-bottom fillet welds size (cl. 5.1.5.7) (iii) Min. width projected inside of shell to edge of overlapping (cl. 5.5.2) (iv) Min. radial width of annular plate (cl. 5.5.2) 215 ta La = 0.5 (HL. SG ) where ta = Annular plate thickness HL = Maximum design liquid level SG = Design specific gravity (v) Min. width projected outside of shell ( cl. 5.5.2)

6.00 mm 9.00 mm

= = = =

mm 25 mm 1800 mm 50 mm

satisfactory.

Min. width of overlapping (cl. 5.1.3.5) Min. width of plate (cl. 5.4.1) -

Annular plate thickness ( As per Table 5-1a ) Minimum thickness required (@ Therefore , use thickness of

= =

=

28.00 mm

=

139.33 N/mm²

= = =

39.028 m 20.700 m 28.000 mm

= =

6.00 mm 9.00 mm

= =

13.00 mm 600 mm

=

756.09 mm

= = = =

16.000 mm 20.70 m 1.00 50 mm

satisfactory.

ROOF TO SHELL JUNCTION CALCULATION

4 .1 4 .1.1

DESIGN OF OPEN ROOF TANK - TOP STIFFENER RING TOP CURB ANGLE If the top wind girder is located 600 mm below top of the tank, top curn angle shall be provided. Location of top wind girders from top of tank, L = Since L is

>

600mm from top of tank, top curb angle is

required.

MINIMUM REQUIREMENT Minimum required size as per API 650 clause 5.9.3.2

=

Section modulus,Z min

=

MEMBER SIZE USED FOR TOP CURB ANGLE Actual size for top curb angle

= 75 x 75x 10

Section modulus, Za

=

Since Za 4 .1.2

1000 mm

>

Zmin , therefore the angle size selected is

76 x 76 x 6.4 3

8380 mm

3

13500 mm

satisfactory.

TOP WIND GIRDER The required minimum section modulus of the stiffening ring shall be as follows:Dc².H2 17

Z= where Dc H2 V

V 190

2

= =

= Nominal Tank Diameter = Height of tank shell = Wind Velocity

= = =

MEMBER SIZE USED FOR TOP WIND GIDER Available section modulus Fabricated Tee- Girder Web plate length, L2 Toe plate length, L3 Web plate thk, t2 Toe plate thk, t3 Min. shell thickness where top wind girder located, tsc.cor tsc.cor = 8.00 mm 10 mm

1007 cm³ 1,007,140 mm³ 39.031 m 20.7 m 140.00 km/hr

: T 825 x 250 x 8 x 10 = 825 mm = 250 mm = 8 mm = 10 mm = 8.00 mm

D=

39037

mm

X 2

C1

8 250 mm 1 3

1 2 3

L1=16.tsc.cor

=

128

mm

X 825 mm A (mm²) 2048 6600 2,500

Y (mm) 4.00 420.5 838.00

TOTAL 11,148 Neutral axis of combined section, C1 Moment of inertia of section , Ix-x Section modulus available Za

AY (mm³) 8192 2775300 2,095,000 4,878,492

h (mm) 433.61141 17.1114101 400.39

A.h² (mm4) 385062615 1932482.35 400,777,557

I = (bd³)/12 (mm4) 10,923 374343750 20,833

787,772,655

374,375,506 438 mm 1,162,148,161 mm 2 655 662 mm³

= = =

INTERMEDIATE WIND GIRDERS CALCULATION 5 .0 5 .1

INTERMEDIATE WIND GIRDERS DESIGN MAXIMUM HEIGHT OF THE UNSTIFFENED SHELL ( CLAUSE 5.9.7.1 )

SI METRIC UNIT :H1 = (9.47 ts.cor)

where

5 .2

ts.cor Dc

3

190 ² V

x

ts.cor = Top shell course thickness Dc = Nominal tank diameter V = Wind design speed LOCATION OF INTERMEDIATE WIND GIRDERS Shell Shell Actual Transposed course thickness width width tsc.cor W Wtr (mm) (mm) (mm) 1 25.00 2,440 141 2 22.00 2,440 195 3 19.00 2,440 281 4 16.00 2,440 431

= =

9.182 m 9182 mm

= = =

8.00 mm 39.03 m 140.00 km/hr

Since H1 < H2, therefore the intermediate wind girder is/are required Minimum number of intermediate wind girders required, = 1 Location of intermediate wind girders from

5 6 7

13.00 10.00 8.00

2,440 2,440 2,020

725 1,397 2,020

top of tank, L1 = L2 =

8 9 10 11 12 13 14 15

8.00 8.00 -

2,020 2,020 -

2,020 2,020 -

L3 L4 L5

Height of transformed shell, H2 =

9,230

mm

= = =

4615 mm - mm - mm - mm - mm

5 .3

SIZE OF INTERMEDIATE WIND GIRDERS (a) Required minimum section modulus of intermediate wind girder ( clause 5.9.7.6 ) SI METRIC UNIT :V 190

Dc². H1 17

Z.min =

2

= =

225.812 cm³ 225,812.032 mm³

where Dc = Nominal tank diameter H1 = Vertical dist. between inter. wind girder & top angle V = Wind design speed

= = =

(b) Available section modulus for intermediate wind girder Fabricated Tee- Girder Web plate length, L2 Toe plate length, L3 Web plate thk, t2 Toe plate thk, t3 Min. shell thickness where top wind girder located, tsc.cor tsc.cor = 8.00 mm 8 mm

39.031 m 4.615 m 140.40 km/hr

: T 405 x 150 = 450 mm = 150 mm = 8 mm = 8 mm = 8.00 mm

D=

39037

mm

X 2

C1

8 150 mm 1 3

L1=16.tsc.cor

=

mm

X 450 mm h (mm) 200.642523 28.3574766 257.36

A.h² (mm4) 82447200.6 2894927.33 79,479,445

TOTAL 6,848 1,401,392 Neutral axis of combined section, C1 Moment of inertia of section , Ix-x Section modulus available, Za Since Za > Zmin , therefore the angle size selected is

164,821,573

1 2 3

128

A (mm²) 2048 3600 1,200

Y (mm) 4.00 233 462.00

AY (mm³) 8192 838800 554,400

I = (bd³)/12 (mm4) 10,923 60750000 6,400 60,767,323 = 205 mm 4 = 225,588,896 mm = 863,143 mm³ satisfactory.

6 .0 6 .1

WIND LOAD CALCULATION (OVERTURNING STABILITY) W IND DESIGN CALCULATION Internal design pressure, Pi ( @ 0.0 mbarg. ) Insulation thickness, ti

= =

Nominal diameter of tank, D Tank height , Hs Roof slope, ß° Roof height, Hr Height from tank bottom to shell centre, Ls Height from tank bottom to roof centre,Lr Min. depth of product (always present in tank) , Hw

= = = = = = =

Weight of tank,Wt (corroded condition) (@ Weight of product (always present in tank) , Ww Weight of shell + top angle (corroded ), W DL (@ 6 .2

6 .3

550,045

kg )

327,512

kg )

WIND FORCE CALCULATION As per API 650 clause 5.2.1(j), the wind pressure are as follows:Wind pressure on conical surfaces, wr (@ 30.00 Wind pressure on cylindrical surfaces, ws (@ 18.00 Wind correction factor, kw (= V /190)²

psf ) psf )

0 N/mm² 75 mm 39,000 mm 20,700 mm 0.000 ° 0 mm 10,350 mm 20,700 mm 0 mm

= = =

5,395,939 N 0N 3,212,898 N

= = =

0.0014369 N/mm² 0.0008621 N/mm² 1.00

Projected area of roof, Ar ( = 0.5.k.Do.Hr ) Projected area of shell, As ( = k.Do.Hs )

= =

0 mm² 811,564,200 mm²

Total wind load exerted on roof, Fr ( = wr.kw.Ar ) Total wind load exerted on shell, Fs ( = ws.kw.As ) Total wind moment on tank, M w ( = Fr.Lr + Fs.Ls )

= = =

0N 699,681 N 7,241,700,964 Nmm

OVERTURNING STABILITY AGAINST WIND LOADING Wind Uplift Load

Internal Pressure Load D/2

Wind load on shell, Fr

H

H/2

Momment about shell to bottom joint Dead Load (W DL)

Liquid hold down weight (wa) For tank to be structurally stable without anchorage, the following uplift criteria shall satisfy: Criteria 1:

0.6 Mw + Mpi < MDL / 1.5

Criteria 2:

Mw + 0.4 Mpi < (MDL +MF) / 2

where: Mpi = = = Mw =

Moment about the shell-to-bottom joint from design internal pressure Uplift thrust on roof due to internal pressure x 1/2 tank diameter 2

( 1/4 π. D . Pi ). 1/2. D Overturning moment about the shell-to-bottom joint from horizontal

=

0 Nmm

= MDL = =

plus vertical wind pressure Total wind moment on tank, ( = Fr.Lr + Fs.Ls ) Moment about the shell-to-bottom joint from the weight of the shell and the roof supported by the s hell. 0.5. D. WDL Weight of roof = 0,since it is floating on liquid

=

7,241,700,964 Nmm

=

62,651,502,376 Nmm

MF = =

Moment about the shell-to-bottom joint from liquid weight (wa) (wa. π D). D 1000 2

= 153,419,379,181 Nmm

wa = H= tb =

Weight of liquid = 59 tb Fby. H Design liquid height Thickness of Bottom plate under the shell

= = =

Fby =

Minimum specified yeid stress of the bottom plate under the shell

=

FOR CRITERIA 1 0.6 Mw + Mpi MDL / 1.5

0.6 Mw + Mpi < MDL / 1.5

FOR CRITERIA 2 Mw + 0.4 Mpi (MDL +MF) / 2

Mw + 0.4 Mpi < (MDL +MF) / 2

= =

64,214.21 N/m 19.2 m 16 mm 2

241 N/mm

4,345,020,578 Nmm 41,767,668,251 Nmm

= 7,241,700,964 Nmm = 108,035,440,779 Nmm

Since, 0.6 Mw + Mpi

<

MDL /1.5, and

Mw +0.4 Mpi

<

1/2 (MDL+ MF)

The tank anchorage is NOT REQUIRED.

7 .0

SEISMIC FORCE CALCULATION

7 .1 7 .1. 1

SEISMIC LOADS DESIGN GEOMETRIC DATA Seismic peak ground acceleration, Sp Importance factor, I Site Class Seismic Use Group, SUG

= = = =

0.3 g 1.50 D III

Nominal diameter of tank, D Total height of tank shell, Ht Ht.from bottom shell to COG of shell,Xs Maximum design liquid level, H Ht.from bottom shell to COG of roof,Xr Design specific gravity of liquid, G

= = = = = =

39,031 mm 20,700 mm 10,350 mm 20,700 mm 0 mm 1

Total weight of tank shell, Ws Total weight of tank roof, Wr Total weight of tank contents, Wp Total weight of tank bottom, Wf

7 .1.2

352,948 kg ) 0 kg ) 24,728,026 kg ) 84,961 kg )

(@ (@ (@ (@

= = = =

3,462,418 0 242,581,931 833,471

N N N N

Note: The total weight of the tank roof will be added to the weight of tan k content, since the roof is floating on the liquid. DESIGN SPECTRAL RESPONSE ACCELERATIONS

Impulsive spectral acceleration parameter, Ai Ai =

I Rwi

2.5 Q Fa So

=

0.34

Convective spectral acceleration parameter, Ac When Tc ≤ TL Ac =

2.5 K Q Fa So

Ts Tc

I Rwc

≤

Ai

=

-

≤

Ai

=

0.063298299

When Tc > TL Ac =

where Q = K = Fa = Fv = So = Rwi = Rwc = TL = Tc = Ts =

2.5 K Q Fa So

Ts .TL Tc

2

I Rwc

Scaling factor Coefficient to adjust the spectral damping from 5% - 0.5% Acceleration based site coefficient as per Table E-1 Velocity-based site coefficient as per Table E-2 Substitution for seismic peak ground acceleration Sp Force reduction coefficient for impulsive mode as per Table E-4 Force reduction coefficient for convective mode as per Table E-4 Regional dependent transition period for longer period ground motion First mode sloshing wave period for convective mode Fv. S1/ Fa. Ss

= = = = = = = =

1 1.5 1.2 1.65 0.3 4 2 4s

= =

6.63 s 0.69

7 .1.3

CONVECTIVE (SLOSHING ) PERIOD The first mode sloshing wave period, Tc = 1.8 Ks √ D where, Ks =

=

6.63 s

=

0.59

=

0.69

= =

1.2 1.6500

= =

0.375 0.75

= =

0.06 0.34

sloshing period coefficient 0.578

Ks =

Ts = where, Fa = Fv = S1 = Ss =

3.68 H D

tanh

Fv . S1 Fa . Ss

Acceleration based site coefficient (at 0.2 sec perios) as per Table E-1 Velocity-based site coefficient (at 1 sec. period) as per Table E-2 Maximum considered earthquake, 5% damped, spectral response acceleration parameter at the period of one second, %g Maximum considered earthquake, 5% damped, spectral response acceleration parameter at shorts period of 0.2 second, %g

For regions outside USA, sites not defined by ASCE 7 method, S1 = 1.25 Sp Ss = 2.5 Sp , the convective spectral acceleration parameter Ac Since Tc > TL and the impulsive spectral acceleration parameter Ai 7 .2 7 .2.1

OVERTURNING STABILITY AGAINST SEISMIC LOADING EFFECTIVE MASS OF TANK CONTENTS Effective impulsive portion of the liquid weight, For D/H ≥ 1.333, Wi =

tanh (0.866.D/H) 0.866. D/H

. Wp

=

D H

. Wp

=

137,636,499.10 N

For D/H < 1.333, Wi = Since

1.0 - 0.218

D/H > 1.333 , effective impulsive portion of the liquid weight, Wi

-

N

=

137,636,499.10 N

=

100,998,137.14 N

Effective convective weight, Wc =

0.230

D H

tanh

3.67H D

. Wp

7 .2.2

CENTER OF ACTION FOR EFFECTIVE LATERAL FORCES The height from the bottom of the Tank Shell to the center of action of the lateral seismic forces related to the impulsive liquid force for ringwall moment, For D/H ≥ 1.333, 0.375H

Xi =

=

7762.5 mm

For D/H < 1.333, Xi =

0.5 - 0.094

D H

.H

D/H > 1.333 , Xi

Since

=

-

mm

=

7,762.50 mm

=

12,722.55 mm

The height from the bottom of the Tank Shell to the center of action of the lateral seismic forces related to the convective liquid force for ringwall moment,

Xc =

7 .2.3

1.0 -

cosh

3.67 H D

3.67H D

sinh

-1 .H

3.67 H D

OVERTURNING MOMENT The seismic overturning moment at the base of the tank shell shall be the SRSS s ummation of the impulsive and convective components multiplied by the respective moment arms to the center of action of the forces. Ringwall moment, [Ai ( Wi. Xi + Ws. Xs + Wr. Xr)]

Mrw =

7 .2.4

=

3.81453E+11 Nmm

=

381453029.8 Nm

SHEAR FORCE The seismic base shear shall be defined as the SRSS combination of the impulsive and convective components. V=

Vi

where,

7 .3 7 .3.1

+ [Ac (Wc. Xc)]

+ Vc Vi = Vc =

Ai (Ws + Wr +Wf + Wi) Ac. Wc

=

48,326,902.75 N

= =

47,902,181.05 N 6,393,010.26 N

RESISTANCE TO OVERTURNING THICKNESS OF THE BOTTOM PLATE UNDER THE SHELL & ITS RADIAL WIDTH Bottom/Annular plate thickness , ta = Thickness of bottom shell course, ts = Bottom/Annular plate radial width, Ls = Min. specified yield strength of bottom annulus, Fy Min. specified yield strength of bottom shell course, Fty

= =

16.00 mm 28.00 mm 1200.0 mm 2

241.0 N/mm 241.0 N/mm

Anchorage Ratio, J J= where, Av = Wt = wa =

Mrw 2 D ( Wt (1 - 0.4 Av) + Wa )

=

Vertical earthquake acceleration coefficient Tank and roof weight acting at base of shell Resisting force of the annulus

= = =

2.17

0.7 28.24 N/mm 94.93 N/mm

Weight of tank shell and portion of roof supported by the shell, Ws Wt = + wrs π. D wrs =

Roof load acting on the shell, including 10% of specified snow load. ( Zero for floating roof)

The resisting force of the annulus, wa = 99 ta Fy. H. Ge wa

≤

<

196. H. D. Ge

=

28.24 N/mm

=

0 N/mm

=

94,932.54 N/m

=

0.72

114,016,732,704.00

196.H.D.Ge =

Ge = Effective specific gravity including vertical seismic effect = G. (1 - 0.4 Av)

Since the anchorage ratio, J > 1.54, the tank is not stable and cannot be self-anchored for the design load. The tank shall be mechanically anchored. 7 .3.2

ANNULAR PLATE REQUIREMENT If the thickness of the bottom plate under the shell is thicker than the remainder of the bottom, then the minimum radial width of the bottom plate, L=

7 .3.3

0.01723 ta

Fy H. Ge

=

1,108.57 mm

The maximum width of annulus for determining the resisting force, 0.035 D

=

1,366.09 mm

Since L And, Since Ls

=

1,108.57 mm

<

0.035 D, the minimum radial width should be

>

L, the bottom/ annular plate width is

satisfactory.

SHELL COMPRESSION MECHANICALLY-ANCHORED TANKS Maximum longitudinal shell compression,

σc = 7 .3.4

wt ( 1 + 0.4 Av) +

1.273 Mrw 2

D

1 ts

=

12.67 N/mm

=

40.223 m³/mm²

=

57.94 N/mm²

MAXIMUM ALLOWABLE SHELL COMPRESSION A=

( D in m )

GHD² ts²

For GHD²/(ts²) < 44 m³/mm², Fc =

83.ts 2.5D

+ 7.5{G.H}

½

For GHD²/(ts²) ≥ 44 m³/mm², Fc =

83.ts D

=

Therefore, Fa ( < 0.5Fty ) Since σc

<

= Fc, therefore the tank is structurally

stable.

-

N/mm²

57.94 N/mm²

7 .4

FREE BOARD FOR SLOSHING WAVE HEIGHT Sloshing wave height above the product design height,

δs = 0.5 D. A f

=

1,647.06 mm

=

0.21

=

0.13

=

0.14

=

0.08

=

0.08

=

1,647.06 mm

= = mm) (min.size.25.4 mm ) = = = =

86 64 mm 58 mm 39,320 mm 2,642 mm² 1,436 mm

where: For SUG I and II, When Tc ≤ 4 A f =

1 Tc

K. SD1. I.

=

2.5 K Q Fa So I

=

2.5 K Q Fa So I

Ts Tc

When Tc > 4 A f =

4

K. SD1. I.

Tc

2

4Ts Tc

2

For SUG III When Tc ≤ TL A f =

1 Tc

K. SD1

=

2.5 K Q Fa So

=

2.5 K Q Fa So

Ts Tc

When Tc > TL A f =

Since SUG is

TL

K. SD1

III

Tc

2

and

For SDS = 0.9 Q Fa Ss = Minimum required freeboard, δsreq 7 .5 7 .5. 1

7 .5.2

Tc > TL

Ts. TL Tc

2

, A f

> 0.33g, ( as per Table E-7)

TANK ANCHORAGE GEOMETRIC DATA Number of bolts , N Dia. of anchor bolt, d Dia. of anchor bolt,d.corr (less c.a.= Bolts circle diameter, Da Root area of each hold down bolt, Ab Spacing between anchor bolts, Sp

3.000

MATERIAL & MECHANICAL PROPERTIES Material used Specific minimum yield stress, Sy Allowable tensile strength, St.all ( 0.80Sy ) ( Table 5-21a )

: = =

SA 320 Gr L7 551.5 N/mm² 441.20 N/mm²

Uplift force due to seismic loading, W AB =

1.273 Mrw Dc²

where Mrw = Dc = wt = Av = wint =

Overturing moment due to seismic Nominal diameter of tank Tank and roof weight acting at base of shell, Vertical earthquake acceleration coefficient

= = = =

3.81453E+11 Nmm 39,031 mm 28.24 N/mm 0.70

Uplift thrust due to internal pressure

=

0 N/mm

=

161.04 N/mm²

- wt ( 1 - 0.4 Av)

+ wint

=

Tensile stress, σb = WAB / N.Ab Since σb

<

St.all,therefore the anchor bolt size is

satisfactory.

36,592,019 N

8 .0

DESIGN OF SINGLE DECK FLOATING ROOF FOR A STORAGE TANK

75 1 64

Top pontoon plt

8 Rafter

L 75 x 75 x 6

Outer Rim

975

Inner Rim

15

Deck Plate

8

Post

525 Btm Angle Bulkhead

198

2181

34248 38610

Shell I.D

39006 ( All dimensions in mm unless otherwise stated. )

8 .1

8 .2

8 .3

TANK GEOMETRY DATA Inside diameter , Di ( corroded ) (@ Tank height (tan/tan), H

39,000

mm )

= =

39,006 mm

Material of Construction Specific Minimum Yield Stress, Sy Modulus of Elasticity Density of Material, ρ (plate)

: SA 516 Gr 65N = 275 N/mm² = 209,000 N/mm² = 7,850 kg/m³

Corrosion Allowance Min. Specific Gravity of product Max. Specific Gravity of product

= = =

GEOMETRY DATA Outer Rim Height, Hor Inner Rim Height, Hir Pontoon width, w Rim Gap Outer Rim Extend above pontoon, Hext

= = = = =

975 525 2181 198 75

No. of Pontoons, N

=

22

Outer Rim Diameter, Øor Inner Rim Diameter, Øir

= =

38610 mm 34248 mm

Bulkhead Outer heigh, Boh Bulkhead Inner heigh, Bih Bulkhead Width, wb

= = =

884 mm 509 mm 2157 mm

MEMBER SIZE & PROPERTIES Outer Rim Thk, Tor Inner Rim Thk, Tir Top Pontoon Thk, Ttp Btm Pontoon Thk, Tbp Bulkheads Thk, Tb Deck Plate Thickness, Td Circumferential Truss Plates

= = = = = = =

Rafter Posts

44 Nos. of 44 Nos. of

L 75 x 75 x 6 L 75 x 75 x 6

@ unit weight of @ unit weight of

3 mm 0.7 1

9 15 8 8 8 8 8

mm mm mm mm mm

mm mm mm mm mm mm mm

6.85 kg/m 6.85 kg/m

8 .4 8 .4. 1

8 .4.2

8 .5

ROOF SUPPORT LEG ( Refer to Design of Supporting Legs) PONTOON LEG No. of Pontoon Leg, Np Pontoon Leg Size 3" pipe x Sch. 80 Pontoon Leg Housing 4" pipe x Sch. 80 Pontoon Leg length Pontoon Leg Housing length DECK LEG No. of Deck Leg, Nd Deck Leg Size Deck Leg Housing Deck Leg length Deck Leg Housing length

=

22 15.27 22.32 2940 1084

kg/m kg/m mm mm

= =

30 15.27 22.32 2927 823

kg/m kg/m mm mm

x( Øor² - Øir²) x Ttp x ρ (plate) x( Øor² - Øir²) x Tbp x ρ (plate)

= =

15,675.18 kg 15,675.18 kg

Øir x Hir x Tir x ρ Øor x Hor x Tor x ρ

= =

6,651.28 kg 8,355.38 kg

@ unit wt @ unit wt = =

=

(Area od deck / 30m² / leg ) 3" pipe x Sch. 80 4" pipe x Sch. 80

@ unit wt @ unit wt

WEIGHT CALCULATION Top Pontoon Bottom Pontoon

=

Inner Rim Outer Rim

= =

π x

Bulkheads

=

1/2 x (Boh - Bih)x wb x Tb x ρ x N

=

2,075.65 kg

Deck Plate

=

π 4

=

57,852.21 kg

π 4 π 4

π x

x Øir x Td x ρ

Pontoon Legs Pontoon Legs housing Deck Legs Deck Legs housing

kg kg kg kg

= = = =

987.66 532.29 1340.86 551.08

= = =

55,248.45 kg 57,852.21 kg 113,100.66 kg

TOTAL WEIGHT

Pontoon Components: Deck Components: -

(Wpontoon) (Wdeck )

Total Weight of Floating Roof, (Wroof)

9 .0

PONTOON VOLUME O. Rim Ø

38610 m

I. Rim Ø + 2 x 2/3 w h3 = 0.03

37156 mm

3 I. Rim Ø

h1 = 0.35

34248 mm

2

h2 = 0.53

1 2

Volume 1

=

40.70 m³

Volume 2

=

120.17 m³

Volume 3

=

3.85 m³

Total Pontoon Volume, Vol(pontoon)

=

164.72 m³

9 .0 9 .1

SETTING DECK LEVEL

OPERATION FLOATATION LEVEL - DECK Deck Floatation Depth Deck Thk

Density of Deck Density of Product

=

ρ (deck) ρ (product)

Floatation Depth, D(deck) =

9 .2

x Td

=

89.71 mm

=

78.93 m³

=

153.15 mm

OPERATION FLOATATION LEVEL - PONTOON Buoyant Force, FB ρ x Vdisplacement x g

Fpontoon W (Pontoon) x g

= =

Pontoon Weight, W(pontoon) ρ (product)

Product Displacement, Vdisplacement =

To find Floatation Depth of Pontoon from Inner Corner of Pontoon, D(pontoon) =

Vol. Displacement above Inner corner of Pontoon Pontoon Cross Area in Vol. 2 Vdisplacement - Vbackslope (Vol.1) 1/4 x π x (Øor² - Øir²)

D(pontoon) =

Freeboard above deck, 494.56 Product Level

3 89.71

2 153.15

Deck Level

1

63.44 m

The Deck is set at the difference of floation depth in Pontoon & Deck, D(deck) - D(pontoon) 9 .3

=

63.44 mm

NORMAL OPERATION FLOATATION LEVEL FOR ROOF - PONTOON & DECK

Actual Product

161.57 m³

Level Deck

Deck

Level

H, Floatation Height Above Deck Total Volume Displaced by the roof

= Volume Displaced by the Backslope, V1 + Partial Volume Displaced in Pontoon below the deck level, Va + Volume Displaced by the Deck, Vb Total Volume Displaced by the roof, Vdisplacement (roof) : Vdisplacement (roof) =

Roof Total Weight, W(roof) ρ (product)

=

161.57 m³

i)

Volume Displaced by the Backslope, Volume 1

ii)

Partial Volume Displaced in Pontoon below the deck level: Deck level Height, h Bulk head outer height, Bih

iii)

x

Vol. 2

40.70

=

14.98 m³

Volume Displaced by the Deck: Area of Deck Plate x Floatation Height Above Deck 2 π 4 x Øir x H

Hence, The Floatation Height Above Deck, H

94

=

=

921.21 H

=

0.11 m 114.95 mm

FLOATATION LEVEL FOR ROOF - PONTOON & DECK FOR 10" (254MM) OF ACCUMULATED RAIN WATER For deck to support 10" (25 4mm) of rain water: Volume of rain water collected at the deck, Vrain = Vrain = Adeck x Hrain

=

233.99

m³

where 2

2

= 921,213,536.64 mm = 254.00 mm

π /4 x Øir Area of deck = Rain accumulation of 10"

Adeck = Hrain =

Total Volume Displaced by the roof with the 10" of rain water accumulation, Vdisplacement (rain) : W(roof) + Wt(rain) Vdisplacement (rain) = = 495.84 ρ (product) where W(roof) =

Total weight of roof

Wt(rain) =

Weight of 10" rain water

Floatation Height above Deck, Vdisplacement (rain) - Vol.1 - partial of Vol.2 (ii) H(rain) = Area of roof 10 0 10 1

= =

m³

0.38 m 375.95 mm

CHECKING THE STRESSES AND DEFLECTION IN THE CENTRE DECK (Ref. to Roark's Formulas For Stress And Strain, 7th Edition) CASE 1: NORMAL CASE - NO PONTOON PUNCTURED

q

α

Et σα

Et Where: t= α= q= = y= σb = σd = σ= v= E=

4

4

=

K

=

K

y 1

2

2

t y

3

t

+

K

+

K

2

4

 y     t 

3

 y     t 

2

( 11.11.1)

Plate thickness, Deck (mm) = Td = Outer radius of the deck plate = Øir / 2 = Unit lateral pressure (equiv. weight of deck that float on product)

( 11.11.2)

8 17124

Td x ( ρ(plate) - ρ(product) ) = 0.000561 Maximum deflection bending stress diaphragm stress σb + σd = Maximum stress due to flexure and diaphragm tension combined Poisson's ratio = 0.3 Modulus of Elasticity = 209,000

2

N/mm

N/mm²

The deck plate is fixed and held at its outer edge by the pontoon, h ence condition is consider as: Fixed and Held. Uniform pressure q over entire plate (Case 3 in Roark's Formulas) 5.33

K1 =

2

=

5.86

2

=

2.86

=

2.86

=

0.976

=

4.40

K4

=

1.73

qα t

=

56,361.13

=

56,249.31

1 - ν 2.6

K2 =

1 - ν

At the Centre, K3 =

2 1 - ν

K4 At the edge, K3 =

For

4 1 - ν

And

y t

K1

+ K2

qα Et

3

=

t

y

215.81 mm

=

Solving equation 11.11.2

²

σα

E. t

=

K3

y t = =

+

K4 787.3494954 1377.567315

y t

2

(at Deck Center) (at Deck Edge)

At Deck Center, σtotal σbending σdiaphgram

= = =

35.92 N/mm 3.52 N/mm 32.40 N/mm

= = =

62.84 N/mm 5.41 N/mm 57.43 N/mm

At Deck Edge, σtotal σbending σdiaphgram

It is the diaphragm stress at the edge which causes the tension at the outer edge of the Deck. Hence, the radial force on the inner rim, σ diaphgram x deck thickness Rh = =

459.44 N/mm

10 2 10 .2.1

PONTOON STRESS DESIGN - CASE 1

PONTOON PROPERTIES Nominal diameter of Inner Rim, Øir Pontoon Inside Width Inner Rim Thickness, Tir Outer Rim Thickness, Tor Top Pontoon Thk, Ttp Btm Pontoon Thk, Tbp

= = = = = =

34248 mm 2160 mm 12 mm 9 mm 8 8

Top Pontoon slope angle @ 1 : 64 = Backslope angle, α =

0.02 rad 0.16 rad

2 2160 525 4 900

α 2187 3

A (mm²) 6300 17282 17494 8100

Y (mm) 6 1092 1092 2176.5

AY (mm³) 37,800 18,872,063 19,103,800 17,629,650 55,643,313

1 2 3 4 49,176 TOTAL Neutral axis of combined section, C1

10 .2.2

10 .2.3

h (mm) 1,126 40 40 1,045

A.h² I = (bd³)/12 (mm4) (mm4) 7,980,578,762 75,600 26,969,435 6,720,924,525 27,300,602 6,971,562,462 8,845,340,202 54,675 16,880,189,001 13,692,617,263 = 1132 mm 4

Moment of inertia of section , Ix-x Section modulus available, Za

= =

30,572,806,264 mm 27,019,626 mm³

MATERIAL PROPERTIES Material Properties Specified minimum yield stress, Sy Yield strength reduction factor, k ( Table M-1 ) Allowable stress reduction factor ( App. M.3.5 ), Ks ( = k.Sy/206.7 ) Allowable bending stress, Fb Allowable compressive stress, Fc

: SA 516 Gr. 65N = 275.00 N/mm² = 1.000 = 1.00 = 183.33 N/mm² = 165.00 N/mm²

PONTOON RING DESIGN The uniform radial force acting on the Inner Rim is modelled as load point at each mm of circumference, with a very small angle between load point approximtaed to uniform distributed load in the circular ring design. Rh α° Mid Point

Number of load point @ each mm, Nlp = π x Øir = 107,593.27 ° Angle α° = 1/2 x 360/ Nlp = 0.001673 Radial load on rim, Rh = 459.44 N ( Note : Rh is negative for inward force )

(Reference to Roark's Formulas For Stress and Strain, 7th Edition, Table 9.2 Case 7)

At Mid-Point, Bending moment,

Circ. tensile force, Rh.Do

Mm

1

1

=

4

sin α

α

Rh.Do

1

1

At Reaction-Point, Bending moment, Mr

=-

Rh Tm

= 2.sin α

Circ. tensile force, -

α 4 tan α ( Do= Qir, nonimial diamter of inner ring)

Rh Tr

= 2 tan α

10 .2.4

RESULT RING STABILITY CHECK

10 .3

MID-POINT

LOAD-POINT

Bending Moment Circumferential force Bending Stress Circu mferential stress

( Nmm ) (N) ( N/mm² ) ( N/mm² )

19.14 7,867,429 0.0000007 159.98

-38.29 7,867,429 -0.000001 159.98

Allow. bending stress Allow. axial stress Unity Check Condition

( N/mm² ) ( N/mm² )

183 165 0.97

183.33 165 0.97

OK.

OK.

CASE 2:

INFLUENCE OF 10" (254mm) OF RAIN ACCUMULATED ON CENTER DECK

10" Rain

For deck to support 10" (25 4mm) of rain water: Volume of rain water collected at the deck, Vrain = Adeck x Hrain where Adeck = Hrain =

=

2

π /4 x Øir Area of deck = Rain accumulation of 10"

233.99

m³

= 921,213,536.64 mm³ = 254 mm

Weight of 10" accumulated rain water, Wrain =

=

233,988.24 kg

Upward Bouyant Load = Deck Area x Floatation Height x Product density 2 = π 4 x (Øir) x H (rain) x ρ

=

242,429.27 kg

Downward load due to deck steel and rain water, = W deck + W rain

=

291,840.45 kg

=

53.64

Vol. rain x ρ rain

Nett downward force acting on deck =

=

75

(Upward bouyant load - Downward Load) Deck Area

q

α

Et σα

Et

4

4

=

K

y 1

2

2

=

K

t y

3

t

+

+

K

K

2

4

 y     t 

3

 y     t 

2

2

kg/m

( 11.11.1)

( 11.11.2)

Where: t= α= q= y= σb = σd = σ= v= E=

Plate thickness, Deck (mm) = Td = Outer radius of the deck plate = Øir / 2 = Unit lateral pressure = Maximum deflection bending stress diaphragm stress σb + σd = Maximum stress due to flexure and diaphragm tension combined Poisson's ratio = Modulus of Elasticity =

8 17124 0.000526 N/mm

0.3 200,000 N/mm²

The deck plate is fixed and held at its outer edge by the pontoon, h ence condition is consider as: Case 3 Fixed and Held. Uniform pressure q over entire plate K1 =

5.33 1 - ν

K2 =

2.6 1 - ν

=

5.86

=

2.86

=

2.86

=

0.976

=

4.40

K4

=

1.73

qα t

=

55,228.70

=

55,140.73

K 3

2 =

1

−

v

At the Centre, K3 =

2 1 - ν

K4 At the edge, K3 =

For

4 1 - ν

And

y t

K1

+ K2

t

y

qα t

=

.

=

mm

Solving equation 11.11.2

²

σα

E. t

=

K3

y t = =

+

K4 777.4581306 1360.154003

y t

2

(at Deck Center) (at Deck Edge)

At Deck Center, σtotal σbending σdiaphgram

= = =

33.94 N/mm 3.34 N/mm 30.60 N/mm

= = =

59.37 N/mm 5.14 N/mm 54.23 N/mm

At Deck edge, σtotal σbending σdiaphgram

It is the diaphragm stress at the edge which causes the tension at the outer edge of the Deck. Hence, the radial force on the inner rim, Rh = = σ diaphgram x deck thickness

433.85 N/mm

10 4 10 .4.1

10 .4.2

10 .4.3

PONTOON STRESS DESIGN - CASE 2

PONTOON PROPERTIES Nominal diameter of Inner Rim, Øir

=

Section modulus available, Za2 = Cross sectional area, Aa

= =

MATERIAL PROPERTIES Material Properties Specified minimum yield stress, Sy Yield strength reduction factor, k ( Table M-1 ) Allowable stress reduction factor ( App. M.3.5 ), Ks ( = k.Sy/206.7 ) Allowable bending stress, Fb Allowable compressive stress, Fc

: SA 516 Gr. 65N = 275.00 N/mm² = 1.000 = 1.00 = 183.33 N/mm² = 165.00 N/mm²

34248 mm 3

27019626.01 mm 49,176 mm²

PONTOON RING DESIGN The uniform radial force acting on the Inner Rim is modelled as load point at each mm of circumference, with a very small angle between load point approximtaed to uniform distributed load in the circular ring design. Rh Number of load point @ each mm, Nlp = π x Øir = 107593.27 ° Angle α° = 1/2 x 360/ Nlp = 0.001673 Radial load on rim, Rh = 433.85 N/ load pt ( Note : Rh is negative for inward force )

α° Mid Point

(Reference to Roark's Formulas For Stress and Strain, 7th Edition, Table 9.2 Case 7)

At Mid-Point, Bending moment,

Circ. tensile force, Rh.Do

Mm

1

1

=

Rh

-

Tm

4

sin α

α

Rh.Do

1

1

2.sin α

At Reaction-Point, Bending moment, Mr

Circ. tensile force,

=

Rh

4

10 .4.4

α

Tr tan α

= 2 tan α

RESULT RING STABILITY CHECK

10 .4.5

=

MID-POINT

LOAD-POINT

Bending Moment Circumferential force Bending Stress Circu mferential stress

( Nmm ) (N) ( N/mm² ) ( N/mm² )

18.08 7,429,209 0.0000007 151.07

-36.15 7,429,209 -0.000001 151.07

Allow. bending stress Allow. axial stress n y ec Condition

( N/mm² ) ( N/mm² )

183 165 .

183 165 .

OK.

OK.

STRESSES SUMMARY LOAD CASE 1 Deck Center Deck Edge

LOAD CASE 2 Deck Center Deck Edge

σtotal

( N/mm² )

35.92

62.84

33.94

59.37

σbending

( N/mm² )

3.52

5.41

3.34

5.14

( N/mm² )

32.40

57.43

30.60

54.23

σdiaphgram

11 .0

ROOF SUPPORT LEG DESIGN

22 15 10 5

11 .1

11 .2

11 .3

Nos. at R4 Nos. at R3 Nos. at R2 Nos. at R1

18541.00 13716.00 8839.00 4267.00

GEOMETRIC DATA Support leg size

= 3" Sch. 80

Pipe outside diameter

= 88.9

mm

Pipe Thickness,

= 7.62

mm

Pipe Area, Aleg Radius of gyration, r =

= 1,945.76

mm

I Aleg

Do2 - Di2 4

MATERIAL PROPERTIES Material of Construction for roof support leg Specific Minimum Yield Stress, Sy Modulus of Elasticity Density of Material, ρ (plate) Leg Material LOADING DATA Support leg length at i) R1 : ii) R2 : iii) R3 : iv) R4 :

2

= 24.89

: SA 333 Gr 6 = 241 N/mm² = 209,000 N/mm² = 7,850 kg/m³

Lsp1 Lsp2 Lsp3 Lsp4

= = = =

2927 2927 2927 2940

mm mm mm mm

Deck O.D Deck Thickness, td

= 34231 =8

Deck Area, Adeck Center deck weight, Wdeck

= 920,299,220.87 = 57,794.79

mm mm 2 mm

Design Live Load, Llive

= 1.2

kg 2

KN/m

Effective radius for area of deck supported by leg: 1/2(Øir/2-R3) = 15415.75 R2eff = 1/2(R3-R2) = 11277.5 R1eff = 1/2(R2-R1) = 6553

R3eff =

Area of deck supported by legs at 2

2

= 134,905,671.69 mm

i)

R1 = π(R1eff )

ii)

R2 = π((R2eff ) - (R1eff ) )

2

2

2

= 264,648,384.82 mm

2

2

= 347,030,823.13 mm

2

2

= 173,714,341.24 mm

iii)

R3 = π((R3eff ) - (R2eff ) )

iv)

R4 = p((Ødeck ) - (R3eff ) )

2 2

11 .4

SUPPORT LEG AT INNER DECK R1 No. of legs at R1

=

Area of deck supported by legs at R1, A1

= 134,905,671.69 mm

Deck area on each leg, A1'

=

Deck load on one leg = Live load on one leg = Total load on one leg =

Wdeck x

2

A1' Adeck

Total Load / Aleg

ALLOWABLE STRESS As per AISC code, Slenderness ratio, λ = K.Lsp1 / Rx-x where K Column slenderness ratio dividing elastic and inelastic buckling, 2π²E Cc = Sy When λ ≤ Cc, [ 1 - λ² / 2Cc² ].Sy Sc.all = (i) 5/3 + 3λ /8Cc - λ³/8Cc³ When Cc ≤ λ ≤ 120, 12π²E Sc.all = (ii) 23 λ² When 120 ≤ λ ≤ 200, Smaller of (i) or (ii) Sc.all = 1.6 - λ /200 In this case, the allowable stress Sc.all is Since P1

11 .5

=

Llive x A1' Deck load + Live load

Stress on support leg at inner deck R1, P1 = 11 .4.1

<

Sc.all, the support leg at inner deck R1 is

2

26,981,134.34 mm 1,694.42 kg

= = =

16.62 KN 32.38 KN 49.00 KN

=

25.18 N/mm

2

=

118

=

1

=

130.84

=

75.08 N/mm²

=

77.80 N/mm²

=

74.20 N/mm²

=

75.08 N/mm²

satisfactory.


=


= 264,648,384.82 mm


=


Wdeck x

10 2

A2' Adeck


Stresses on support leg at inner deck R2, P2 = 11 .5.1

5

ALLOWABLE STRESS As per AISC code, Slenderness ratio, λ = K.Lsp2 / Rx-x where K Column slenderness ratio dividing elastic and inelastic buckling, 2π²E Cc = Sy

=

2

26,464,838.48 mm 1,661.99 kg

= = =

16.30 KN 31.76 KN 48.06 KN

=

24.70 N/mm

2

=

118

=

1

=

130.84

When λ ≤ Cc, [ 1 - λ² / 2Cc² ].Sy Sc.all

=

5/3 + 3λ /8Cc - λ³/8Cc³ When Cc ≤ λ ≤ 120, 12π²E Sc.all = 23 λ² When 120 ≤ λ ≤ 200, Smaller of (i) or (ii) Sc.all = 1.6 - λ /200 In this case, the allowable stress Sc.all is Since P2 11 .6

<

=

75.08 N/mm²

(ii)

=

77.80 N/mm²

=

74.20 N/mm²

=

75.08 N/mm²


satisfactory.


=


= 347,030,823.13 mm


=


Wdeck x

A3' Adeck

Total Load / Aleg

<


2

23,135,388.21 mm

=


15 2


Stresses on support leg at inner deck R3, P3 = 11 .6.1

(i)

1,452.90 kg

= = =

14.25 KN 27.76 KN 42.02 KN

=

21.59 N/mm

=

118

=

1

=

130.84

=

75.08 N/mm²

=

77.80 N/mm²

=

74.20 N/mm²

=

75.08 N/mm²

satisfactory.

11 .7

SUPPORT LEG AT PONTOON

No. of legs at R4

=


= 173,714,341.24 mm


=

Deck load on one leg =

Wdeck x

2

A4' Adeck

Llive x A4' Deck load + Live load + Pontoon weight

Stresses on support leg at Pontoon, P4 = 11 .7.1


11 .8

Total Load / Aleg

<


STRESSES SUMMARY

Leg at radius

No. of leg

4267.00 8839.00 13716.00 18541.00

5.00 10.00 15.00 22.00

Actual stress, (N/mm2) 25.18 24.70 21.59 31.33

Allowable stress, (N/mm2) 75.08 75.08 75.08 74.62

RESULT OK OK OK OK

2

6,433,864.49 mm

=

Pontoon weight, Wpontoon Pontoon weight on one leg, Wpontoon' Live load on one leg = Total load on one leg =

27

= = = = = = =

404.05 kg 3.96 KN 55,248.45 kg 5,022.59 kg 49.27 KN 7.72 KN 60.96 KN 2

31.33 N/mm

=

118

=

1

=

130.84

=

74.62 N/mm²

=

77.12 N/mm²

=

73.93 N/mm²

=

74.62 N/mm²

satisfactory.

BLEEDER VENT CALCULATION

12 .0 12 .1

DESIGN OF AIR VENTING SYSTEM GEOMETRIC DATA Design Code Inside diameter, Di Tank height, H Nominal Capacity Design pressure, Pi Flash point (FP)/Normal boiling point (NBP) (@ Filling rate ( Pumping in/Flow rate to tank ), Vi Emptying rate ( Pumping out/Flow rate from tank ), Vo

FP

)

: API STD 2000 = 39000 = 20700 24000 = 2.50 = 67 = 427 = 1,100

mm mm m³ mbarg °C m³/hr m³/hr

OPERATING VENTING

12 .2 12 .2.1

12 .2.2

12 .3 12 .3.1

12 .3.2

12 .4

NORMAL VACUUM VENTING Maximum liquid movement out of a tank Flow rate of free air, Vv1 ( = Vo/15.9 x 15.89 ) Thermal inbreathing Tank capacity, V From Table 2, column 2 (Thermal Venting Capacity Req't ), Flow rate of free air,Vv2 (@ 0 ft³/hr )

=

1097.23 m³/hr

=

155,535 arrels

=

0 m³/hr

Total vacuum flow required, Vv ( = Vv1 + Vv2 )

=

1,097 m³/hr

NORMAL PRESSURE VENTING Maximum liquid movement into a tank Rate of free air per 0.159m³/hr of product import rate, m Flow rate of free air, Vp1 ( = Vi/0.159 x m )

= =

0.17 m³/hr 457 m³/hr

Thermal outbreathing From Table 2, column 3 (Thermal Venting Capacity Req't), Flow rate of free air,Vp2 (@ 0 ft³/hr )

=

Total pressure flow required, Vp ( = Vp1 + Vp2 )

=

457 m³/hr

=

1,097 m³/hr

0 m³/hr

OPEN VENT SIZING ( BLEEDER VENT SIZING ) OPEN VENT SIZING CALCULATION

Maximum flow, Q ( @ Q=

Vacuum

flow at ( @

2.50

mbarg. )

K. A. 2. g. H

where K= A= g= H=

Discharge coefficient cross sectional area of vent acceleration due to gravity Head as measure pressure differential D p H= g

0.62

=

21 m

Minimum require cross sectional area of vent, A

_req

where Q= g= r= D p =

12 .5

=

Q K. 2. g. H

=

Q g K 2. g. D p

Max. Air flow required Specific weight of Air Air densit Differential pressure

= rg

BLEEDER VENT SELECTED Selected bleeder vent size Number of vent, N Outside diameter of the vent, do Inside Dia. of one vent , di ( @ vent pipe thickness = 8.18 mm ) Total cross sectional area of vents, A _actual Since A _actual > Ar_gnv, therefore the nos. & size of vents is

= =

0.0241 m² 24,124 mm²

=

0.3048 mm³/s

= = =

11.812 kg/m s 1.204 kg/m³ 250 N/m²

: =

8" Sch Std 1 219 = 202.64 mm = 32,251 mm² satisfactory.

2 2

13 .0

ROOF DRAIN DESIGN

Rigid Pipe

1275

Flexible pipe

225 Rigid Pipe 13 .1

GEOMETRIC DATA Tank Nominal Diameter Tank Height, Roof lowest height, H Drain outlet nozzle elevation, z

= = = =

39,000 20,100 1500 225

Roof Deck Area

=

920.30 m

Design Rain Fall

=

50 mm/hr

Design drainage required, Qreq.

=

46.01 m / hr

No. of Roof Drain, N Roof drain pipe size (rigid & fitting) Dain Pipe Outside Diameter, Do Drain pipe thickness

= = = =

2 4" Sch 80 101.6 mm 8.56 mm

= =

40 m 23.14 m

Drain Pipe length : L1 = Rigid L2 = Flexible 13 .2

20 m x 23.14 m x

Number of Fitting & Accessories per drain pipe - 45º elbow - 90º elbow

TOTAL HEAD 2

H = h +

nos. nos.

=

2

N90

=

1

Nv

= = =

1 2 1

º

V 2g

2

3

N45

º

- Valve - Rigid pipe - Flexible pipe 13 .3

2 1

mm mm mm mm

13 .4

TOTAL HEAD LOSS OF ROOF DRAIN PIPE 2

h= Where H = G = K =

L' = D = 13 .5

V x 2g

K L' D

Total head between the lowest position of deck and the roof drain nozzle Gravity acceleration Friction Coefficient - For rigid pipe : - For flexible pipe : Total equivalent length of drain pipe Inside Diameter of drain pipe

=

1.275

K1

=

0.0168

K2

=

0.03

=

0.08448

Accordance to NFPA 15 Table 8.5.2.1, 45º elbow, L45 Equivalent length for 4"

=

3.1

90º elbow, L90

=

1.2

Valve, Lv

=

0.6

º

Total equivalent pipe length for RIGID PIPE: L1' = L1 + N45 x L45º + N90º x L90º + Nv x Lv

=

48 m

Total equivalent pipe length for Flexible PIPE: L2' = L2

=

23.14 m

º

TOTAL HEAD LOSS OF ROOF DRAIN PIPE h=

H= 13 .7

m

EQUIVALENT PIPE LENGTH OF VALVE AND FITTING º

13 .6

m

V

2

2g

V

2

2g

x

K1 L1' D

+

K2 L2' D

K1 L1' D

+

K2 L2' + 1 D

FLOW VELOCITY 2gH V=

13 .8

K1 L1' D

+

K2 L2' + 1 D

1.15 m/s

DRAINAGE FLOW RATE PER DRAIN PIPE Q = AREA x Velocity 2

= π /4 x D x V x 3600 (s/hr) 13 .9

=

MINIMUM ROOF DRAIN REQUIRED Drainage flow rate required Nreq = Actual flow rate per drain MINIMUM REQUIRED

3

=

23.30 m / hr

=

=

1.97

2

Storage Tank

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