Storage Tank
Content
APPENDIX B (DESIGN CALCULATION)
STORAGE TANK DESIGN CALCULATION - API 650 1 .0 DESIGN CODE & SPECIFICATION DESIGN CODE TANK Item number Roof ( Open/Close ) Type of roof ( Cone-roof / Dome-roof / Flat-roof / NA ) 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 MATERIAL & MECHANICAL PROPERTIES Component Material Tensile Stress St(N/mm²) 448.00 448.00 448.00 448.00 448.00 448.00 448.00 448.00 Yield Stress Sy(N/mm²) 241.00 241.00 241.00 241.00 241.00 241.00 241.00 241.00 Corrosion Allowance c.a.(mm) 3.000 3.000 3.000 3.000 3.000 3.00 3.00 3.00
: API 650 11th Edition
1 .1
: 7061T-3901 : Close : Floating Roof
1 .2
= = = = = = = =
39,006 39,028 39,031 20,700 0.790 1.00 24736 20,700
mm mm mm mm
m³ mm
1 .3
(Atmospheric) = = = =
0.00 0.00 70 -17
mbarg mbarg Vac °C °C
1 .4
PLATE Shell Plate
( Mat'l Code # 1 ) (bot) ( Mat'l Code # 2 ) (top)
Annular Plate Bottom Plate Roof Plate STRUCTURE MEMBERS Roof structure (rafter,bracing,etc ) Top Curb Angle Intermediate Wind Girder
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 .0 2 .1
SHELL THICKNESS CALCULATION BY ONE-FOOT METHOD SHELL DESIGN GEOMETRIC DATA Plate size used PTS 34.51.01.31 clause 6.3 Shell plate min. width as per MATERIAL & MECHANICAL PROPERTIES Material used Specified Specified Yield stress Max. allow Max. allow min. tensile min. yield reduction fac design hydro.test stress stress ( App. M ) stress stress St (N/mm²) Sy (Nmm²) k Sd (N/mm²) St (N/mm²) 448.00 448.00 448.00 448.00 448.00 448.00 448.00 448.00 448.00 241.00 241.00 241.00 241.00 241.00 241.00 241.00 241.00 241.00 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 160.67 160.67 160.67 160.67 160.67 160.67 160.67 160.67 160.67 180.75 180.75 180.75 180.75 180.75 180.75 180.75 180.75 180.75 -
: :
2,440 mm 1,500 mm
2 .2 No
Corrosion allowance c.a (mm) 3.00 3.00 3.00 3.00 3.00 3.00 3.00 3.00 3.00 -
1 2 3 4 5 6 7 8 9 10
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 .3
SPECIFIED MINIMUM SHELL THICKNESS Specification Minimum thickness as per API 650 cl 5.6.1.1 PTS 34.51.01.31 Minimum thickness as per
: API 650 11th Edition = 8.00 mm = 11.00 mm
2 .4
SHELL THICKNESS CALCULATION BY ONE-FOOT METHOD ( CLAUSE 5.6.3.1 ) 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
t.min = Min. of t.design, t.hydo & min. thickness as per PTS. tsc = Thicknes selected & used
2 .5 No. Mat'l Code No. 1 2 3 4 5 6 7 8 9 1 1 1 1 1 1 1 1 1
CALCULATION & RESULTS Material Width (mm) Height (mm) t.design (mm) t.hydro. (mm) t.min (mm) tsc. (mm) Result
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
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 No.
MAXIMUM ALLOWABLE STRESS 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 H' = H' max = P'max = Pmax =
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
Effective liquid head at design pressure Max. liquid head for tsc. Max. allowable stress for tsc. Max. allowable stress at shell course.
3 .0
BOTTOM & ANNULAR PLATE DESIGN 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
= = satisfactory. == = =
6.00 mm 9.00 mm
Min. width of overlapping (cl. 5.1.3.5) Min. width of plate (cl. 5.4.1) -
mm 25 mm 1800 mm 50 mm
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 Annular plate thickness ( As per Table 5-1a ) Minimum thickness required (@ 3.00 16.00 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
mm c.a. ) mm (ta) is
satisfactory. = = = = = = = 13.00 mm 600 mm 756.09 mm 16.000 mm 20.70 m 1.00 50 mm
(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 = (HL. SG )0.5 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)
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.
1000 mm
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 Section modulus, Za Since Za 4 .1.2 > Zmin , therefore the angle size selected is
= =
76 x 76 x 6.4 8380 mm3
= 75 x 75x 10 = satisfactory. 13500 mm
3
TOP WIND GIRDER The required minimum section modulus of the stiffening ring shall be as follows:Z= where Dc H2 V Dc².H2 17 V 190
2
= = = = =
1007 cm³ 1,007,140 mm³ 39.031 m 20.7 m 140.00 km/hr
= 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 X 2 8 250 mm 1 X 825 mm L1=16.tsc.cor C1 D= 39037
: T 825 x 250 x 8 x 10 = 825 mm = 250 mm = 8 mm = 10 mm = 8.00 mm
mm
=
128
mm
3
A Y AY h (mm²) (mm) (mm³) (mm) 1 2048 4.00 8192 433.61141 2 6600 420.5 2775300 17.1114101 3 2,500 838.00 2,095,000 400.39 TOTAL 11,148 4,878,492 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
A.h² (mm4) 385062615 1932482.35 400,777,557 787,772,655
I = (bd³)/12 (mm4) 10,923 374343750 20,833 374,375,506 = 438 mm = 1,162,148,161 mm4 = 2,655,662 mm³ satisfactory.
5 .0 5 .1
INTERMEDIATE WIND GIRDERS CALCULATION INTERMEDIATE WIND GIRDERS DESIGN MAXIMUM HEIGHT OF THE UNSTIFFENED SHELL ( CLAUSE 5.9.7.1 )
SI METRIC UNIT :H1 = (9.47 ts.cor) where ts.cor Dc
3
x
190 ² V
= = = = =
9.182 m 9182 mm 8.00 mm 39.03 m 140.00 km/hr
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 5 13.00 2,440 725 6 10.00 2,440 1,397 7 8.00 2,020 2,020 8 8.00 2,020 2,020 9 8.00 2,020 2,020 10 11 12 13 14 15 Height of transformed shell, H2 = 9,230 mm
5 .2
Since H1 < H2, therefore the intermediate required wind girder is/are Minimum number of intermediate wind girders required, = 1 Location of intermediate wind girders from top of tank, L1 = 4615 mm L2 = - mm L3 = - mm - mm L4 = L5 = - 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 :Z.min = 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 X 2 8 150 mm 1 X 450 mm L1=16.tsc.cor = 128 mm C1 D= 39037 = = = 39.031 m 4.615 m 140.40 km/hr Dc². H1 17 V 190
2
= =
225.812 cm³ 225,812.032 mm³
: T 405 x 150 = 450 = 150 8 = = 8 = 8.00
mm mm mm mm mm
mm
3
A Y AY h (mm²) (mm) (mm³) (mm) 1 2048 4.00 8192 200.642523 2 3600 233 838800 28.3574766 3 1,200 462.00 554,400 257.36 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
A.h² (mm4) 82447200.6 2894927.33 79,479,445 164,821,573
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) WIND 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 ), WDL (@ 550,045 327,512 kg ) kg )
= = = = = = = = = = = =
0 N/mm² 75 mm 39,000 20,700 0.000 0 10,350 20,700 0 mm mm ° mm mm mm mm
5,395,939 N 0N 3,212,898 N
6 .2
WIND FORCE CALCULATION As per API 650 clause 5.2.1(j), the wind pressure are as follows:30.00 Wind pressure on conical surfaces, wr (@ Wind pressure on cylindrical surfaces, ws (@ 18.00 Wind correction factor, kw (= V /190)² Projected area of roof, Ar ( = 0.5.k.Do.Hr ) Projected area of shell, As ( = k.Do.Hs ) 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, Mw ( = Fr.Lr + Fs.Ls )
psf ) psf )
= = = = = = = =
0.0014369 N/mm² 0.0008621 N/mm² 1.00 0 mm² 811,564,200 mm² 0N 699,681 N 7,241,700,964 Nmm
6 .3
OVERTURNING STABILITY AGAINST WIND LOADING Wind Uplift Load
Internal Pressure Load D/2
Wind load on shell, Fr H/2
H
Momment about shell to bottom joint Dead Load (WDL)
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
=
0 Nmm
Overturning moment about the shell-to-bottom joint from horizontal
= 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 shell. 0.5. D. WDL Weight of roof = 0,since it is floating on liquid Moment about the shell-to-bottom joint from liquid weight (wa) (wa. π D). D 1000 2 Weight of liquid = 59 tb Fby. H Design liquid height Thickness of Bottom plate under the shell Minimum specified yeid stress of the bottom plate under the shell 0.6 Mw + Mpi < MDL / 1.5
=
7,241,700,964 Nmm
= 62,651,502,376 Nmm
MF = =
= 153,419,379,181 Nmm
wa = H= tb = Fby =
= = = =
64,214.21 N/m 19.2 m 16 mm
2 241 N/mm
FOR CRITERIA 1 0.6 Mw + Mpi MDL / 1.5 FOR CRITERIA 2 Mw + 0.4 Mpi (MDL +MF) / 2 Since, 0.6 Mw + Mpi Mw +0.4 Mpi
= 4,345,020,578 Nmm = 41,767,668,251 Nmm Mw + 0.4 Mpi < (MDL +MF) / 2 = 7,241,700,964 Nmm = 108,035,440,779 Nmm
< <
MDL/1.5, and 1/2 (MDL+ MF)
The tank anchorage is NOT REQUIRED.
7 .0 7 .1 7 .1.1
SEISMIC FORCE CALCULATION SEISMIC LOADS DESIGN GEOMETRIC DATA Seismic peak ground acceleration, Sp Importance factor, I Site Class Seismic Use Group, SUG 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 Total weight of tank shell, Ws Total weight of tank roof, Wr Total weight of tank contents, Wp Total weight of tank bottom, Wf (@ (@ (@ (@ 352,948 0 24,728,026 84,961 kg ) kg ) kg ) kg )
= = = = = = = = = = = = = =
0.3 g 1.50 D III 39,031 20,700 10,350 20,700 0 1 3,462,418 0 242,581,931 833,471 mm mm mm mm mm
N N N N
7 .1.2
Note: The total weight of the tank roof will be added to the weight of tank content, since the roof is floating on the liquid. DESIGN SPECTRAL RESPONSE ACCELERATIONS Impulsive spectral acceleration parameter, Ai Ai = 2.5 Q Fa So I Rwi = 0.34
Convective spectral acceleration parameter, Ac When Tc ≤ TL Ac = 2.5 K Q Fa So Ts Tc I Rwc ≤ Ai = -
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
≤ Ai
=
0.063298299
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
sloshing period coefficient 0.578
Ks =
tanh
3.68 H D
=
0.59
Ts = where, Fa = Fv = S1 = Ss =
Fv . S1 Fa . Ss
=
0.69
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
= =
1.2 1.6500
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 = For D/H < 1.333, Wi = Since 1.0 - 0.218 D H . Wp tanh (0.866.D/H) 0.866. D/H . Wp
= = = =
0.375 0.75 0.06 0.34
= 137,636,499.10 N
=
-
N
D/H > 1.333 , effective impulsive portion of the liquid weight, Wi
= 137,636,499.10 N
Effective convective weight, Wc = 0.230 D H tanh 3.67H D . Wp = 100,998,137.14 N
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, Xi = For D/H < 1.333, Xi = Since 0.5 - 0.094 D .H H = = mm 0.375H = 7762.5 mm
D/H > 1.333 , Xi
7,762.50 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, cosh Xc = 1.0 3.67H D 3.67 H D sinh -1 3.67 H D .H = 12,722.55 mm
7 .2.3
OVERTURNING MOMENT The seismic overturning moment at the base of the tank shell shall be the SRSS summation of the impulsive and convective components multiplied by the respective moment arms to the center of action of the forces. Ringwall moment, Mrw = [Ai ( Wi. Xi + Ws. Xs + Wr. Xr)]
2
+ [Ac (Wc. Xc)]
2
= =
3.81453E+11 Nmm 381453029.8 Nm
7 .2.4
SHEAR FORCE The seismic base shear shall be defined as the SRSS combination of the impulsive and convective components. V= where, Vi2 + Vc2 Vi = Vc = Ai (Ws + Wr +Wf + Wi) Ac. Wc = = = 48,326,902.75 N 47,902,181.05 N 6,393,010.26 N
7 .3 7 .3.1
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 Anchorage Ratio, J J= where, Av = Wt = wa = Mrw D2 ( Wt (1 - 0.4 Av) + Wa ) = = =
16.00 mm 28.00 mm 1200.0 mm 241.0 N/mm 2 241.0 N/mm
2
2.17
Vertical earthquake acceleration coefficient Tank and roof weight acting at base of shell Resisting force of the annulus
= = =
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)
=
28.24 N/mm
=
0 N/mm
The resisting force of the annulus, wa = 99 ta Fy. H. Ge wa < 196.H.D.Ge =
≤ 196. H. D. Ge 114,016,732,704.00
=
94,932.54 N/m
Ge = Effective specific gravity including vertical seismic effect = G. (1 - 0.4 Av)
=
0.72
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= 0.01723 ta Fy H. Ge = = = 1,108.57 mm 1,366.09 mm 1,108.57 mm
The maximum width of annulus for determining the resisting force, 0.035 D Since L And, Since Ls 7 .3.3 < > 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 = wt ( 1 + 0.4 Av) + 1.273 Mrw D
2
1 ts = 12.67 N/mm
7 .3.4
MAXIMUM ALLOWABLE SHELL COMPRESSION A= GHD² ts² ( D in m ) = 40.223 m³/mm²
For GHD²/(ts²) < 44 m³/mm², Fc = 83.ts 2.5D + 7.5{G.H}½
=
57.94 N/mm²
For GHD²/(ts²) ≥ 44 m³/mm², Fc = 83.ts D = N/mm²
Therefore, Fa ( < 0.5Fty ) Since σc < Fc, therefore the tank is structurally stable.
=
57.94 N/mm²
7 .4
FREE BOARD FOR SLOSHING WAVE HEIGHT Sloshing wave height above the product design height, δs = 0.5 D. Af where: For SUG I and II, When Tc ≤ 4 Af = When Tc > 4 Af = For SUG III When Tc ≤ TL Af = When Tc > TL Af = Since SUG is K. SD1 III TL Tc and
2
=
1,647.06 mm
K. SD1. I.
1 Tc
=
2.5 K Q Fa So I
Ts Tc
=
0.21
K. SD1. I.
4 Tc
2
=
2.5 K Q Fa So I
4Ts Tc
2
=
0.13
K. SD1
1 Tc
=
2.5 K Q Fa So
Ts Tc
=
0.14
=
2.5 K Q Fa So Tc > TL
Ts. TL Tc , Af
2
= =
0.08 0.08
For SDS = 0.9 Q Fa Ss = Minimum required freeboard, δsreq 7 .5 7 .5.1 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
> 0.33g, ( as per Table E-7)
=
1,647.06 mm
3.000
= = mm) (min.size.25.4 mm ) = = = =
86 64 58 39,320 2,642 1,436
mm mm mm mm² mm
7 .5.2
MATERIAL & MECHANICAL PROPERTIES Material used Specific minimum yield stress, Sy Allowable tensile strength, St.all ( 0.80Sy ) ( Table 5-21a ) Uplift force due to seismic loading, W AB = where Mrw = Dc = wt = Av = wint = 1.273 Mrw Dc² - wt ( 1 - 0.4 Av) + wint
: = =
SA 320 Gr L7 551.5 N/mm² 441.20 N/mm²
=
36,592,019 N
Overturing moment due to seismic Nominal diameter of tank Tank and roof weight acting at base of shell, Vertical earthquake acceleration coefficient Uplift thrust due to internal pressure
= = = = =
3.81453E+11 39,031 28.24 0.70 0
Nmm mm N/mm N/mm
Tensile stress, σb = WAB / N.Ab Since σb < St.all,therefore the anchor bolt size is satisfactory.
=
161.04 N/mm²
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
Inner Rim
Outer Rim
15
975
Post
525
Btm Angle Bulkhead Deck Plate
8
198
2181 38610
Shell I.D
34248
39006 ( All dimensions in mm unless otherwise stated. )
8 .1
TANK GEOMETRY DATA Inside diameter , Di ( corroded ) (@ Tank height (tan/tan), H Material of Construction Specific Minimum Yield Stress, Sy Modulus of Elasticity Density of Material, ρ (plate) Corrosion Allowance Min. Specific Gravity of product Max. Specific Gravity of product
39,000
mm )
= =
39,006 mm
: SA 516 Gr 65N = 275 N/mm² 209,000 N/mm² = = 7,850 kg/m³ = = = 3 mm 0.7 1
8 .2
GEOMETRY DATA Outer Rim Height, Hor Inner Rim Height, Hir Pontoon width, w Rim Gap Outer Rim Extend above pontoon, Hext No. of Pontoons, N Outer Rim Diameter, Øor Inner Rim Diameter, Øir Bulkhead Outer heigh, Boh Bulkhead Inner heigh, Bih Bulkhead Width, wb
= = = = = = = = = = =
975 525 2181 198 75 22
mm mm mm mm mm
38610 mm 34248 mm 884 mm 509 mm 2157 mm
8 .3
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
= = = = = = =
9 15 8 8 8 8 8
mm mm mm mm mm mm mm
6.85 kg/m 6.85 kg/m
8 .4 8 .4.1
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 WEIGHT CALCULATION Top Pontoon Bottom Pontoon Inner Rim Outer Rim Bulkheads Deck Plate =
= @ unit wt @ unit wt = =
22 15.27 22.32 2940 1084
kg/m kg/m mm mm
8 .4.2
(Area od deck / 30m² / leg ) 3" pipe x Sch. 80 4" pipe x Sch. 80
= @ unit wt @ unit wt = =
30 15.27 22.32 2927 823
kg/m kg/m mm mm
8 .5
π /4 x( Øor² - Øir²) x Ttp x ρ (plate) π /4 x( Øor² - Øir²) x Tbp x ρ (plate) π x Øir x Hir x Tir x ρ π x Øor x Hor x Tor x ρ
1/2 x (Boh - Bih)x wb x Tb x ρ x N
= = = = = = = = = =
15,675.18 kg 15,675.18 kg 6,651.28 kg 8,355.38 kg 2,075.65 kg 57,852.21 kg 987.66 532.29 1340.86 551.08 kg kg kg kg
= = = =
π /4 x Øir x Td x ρ
Pontoon Legs Pontoon Legs housing Deck Legs Deck Legs housing TOTAL WEIGHT Pontoon Components: (Wpontoon) Deck Components: (Wdeck) Total Weight of Floating Roof, (Wroof)
= = =
55,248.45 kg 57,852.21 kg 113,100.66 kg
9 .0
PONTOON VOLUME O. Rim Ø I. Rim Ø + 2 x 2/3 w h3 = 0.03 3 I. Rim Ø h2 = 0.53 h1 = 0.35 1 2 Volume 1 Volume 2 Volume 3 Total Pontoon Volume, Vol(pontoon) = = = = 40.70 m³ 120.17 m³ 3.85 m³ 164.72 m³ 2 34248 mm 38610 mm 37156 mm
9 .0 9 .1
SETTING DECK LEVEL OPERATION FLOATATION LEVEL - DECK Deck Floatation Depth Deck Thk Floatation Depth, D(deck) = = Density of Deck Density of Product
ρ (deck) ρ (product)
x Td
=
89.71 mm
9 .2
OPERATION FLOATATION LEVEL - PONTOON Buoyant Force, FB ρ x Vdisplacement x g = = Fpontoon W (Pontoon) x g Pontoon Weight, W(pontoon) ρ (product) = 78.93 m³
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) = 153.15 mm
D(pontoon) =
3 2 153.15 1 The Deck is set at the difference of floation depth in Pontoon & Deck, D(deck) - D(pontoon) 9 .3 = 63.44 mm 89.71
Freeboard above deck, 494.56 Product Level Deck Level 63.44 mm
NORMAL OPERATION FLOATATION LEVEL FOR ROOF - PONTOON & DECK
Actual Product Level Deck Level
161.57 m³ Deck
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
=
40.70
ii)
Partial Volume Displaced in Pontoon below the deck level: Deck level Height, h Bulk head outer height, Bih x Vol. 2 = 14.98 m³
iii)
Volume Displaced by the Deck: Area of Deck Plate x Floatation Height Above Deck π /4 x Øir 2 x H
= =
921.21 H 0.11 m 114.95 mm
Hence, The Floatation Height Above Deck, H
94
FLOATATION LEVEL FOR ROOF - PONTOON & DECK FOR 10" (254MM) OF ACCUMULATED RAIN WATER For deck to support 10" (254mm) of rain water: Volume of rain water collected at the deck, Vrain = Vrain = Adeck x Hrain where Adeck = Hrain =
=
233.99
m³
π /4 x Øir 2 Area of deck = Rain accumulation of 10"
2 = 921,213,536.64 mm = 254.00 mm
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) = Wt(rain) = Total weight of roof Weight of 10" rain water
m³
Floatation Height above Deck, H(rain) = Vdisplacement (rain) - Vol.1 - partial of Vol.2 (ii) Area of roof 10 0 10 1 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
= =
0.38 m 375.95 mm
qα Et
4 4
= K
1
y + K t
2
y t
3
( 11.11.1)
σα
Et
Where: t= α= q= = y= σb = σd = σ= v= E=
2 2
= K
3
y + K t
4
y t
2
( 11.11.2)
Plate thickness, Deck (mm) = Td = Outer radius of the deck plate = Øir / 2 = Unit lateral pressure (equiv. weight of deck that float on product)
8 17124 N/mm2
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
N/mm²
The deck plate is fixed and held at its outer edge by the pontoon, hence condition is consider as: Fixed and Held. Uniform pressure q over entire plate (Case 3 in Roark's Formulas) K1 = K2 = At the Centre, K3 = K4 At the edge, K3 = K4 For 4 1 - ν2 = = = 4.40 1.73 56,361.13 2 1- ν = = 2.86 0.976 5.33 1 - ν2 2.6 1 - ν2 = = 5.86 2.86
q α4 Et4
3
And
K1
y t
+ K2
y
y t
= =
q α4 Et4 215.81 mm
=
56,249.31
Solving equation 11.11.2 σα² E. t 2 = K3 y t = = At Deck Center, + K4 787.3494954 1377.567315 y t 2
(at Deck Center) (at Deck Edge)
2 35.92 N/mm 2 N/mm 3.52 2 32.40 N/mm
σtotal σbending σdiaphgram
At Deck Edge,
= = =
σtotal σbending σdiaphgram
= = =
2 62.84 N/mm 2 5.41 N/mm 2 57.43 N/mm
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 =
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 2160 12 9 8 8 mm mm mm mm
2 2160 525 4 900 α 2187 3
Top Pontoon slope angle @ 1 : 64 = Backslope angle, α = A Y (mm²) (mm) 1 6300 6 2 17282 1092 3 17494 1092 4 8100 2176.5 TOTAL 49,176 Neutral axis of combined section, C1 Moment of inertia of section , Ix-x Section modulus available, Za 10 .2.2 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 AY (mm³) 37,800 18,872,063 19,103,800 17,629,650 55,643,313 h (mm) 1,126 40 40 1,045
0.02 rad 0.16 rad
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 = = 30,572,806,264 mm4 27,019,626 mm³
: SA 516 Gr. 65N = 275.00 N/mm² = 1.000 = 1.00 = 183.33 N/mm² = 165.00 N/mm²
10 .2.3
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, Rh.Do Mm = 4 At Reaction-Point, Bending moment, Rh.Do Mr =1 1 Tr = 2 tan α sin α 1 α 1 Tm = 2.sin α
Circ. tensile force, Rh
Circ. tensile force, Rh
4 α tan α ( Do= Qir, nonimial diamter of inner ring)
10 .2.4
RESULT RING STABILITY CHECK Bending Moment Circumferential force Bending Stress Circumferential stress Allow. bending stress Allow. axial stress Unity Check Condition ( Nmm ) (N) ( N/mm² ) ( N/mm² ) ( N/mm² ) ( N/mm² ) MID-POINT 19.14 7,867,429 0.0000007 159.98 183 165 0.97 OK. LOAD-POINT -38.29 7,867,429 -0.000001 159.98 183.33 165 0.97 OK.
10 .3
CASE 2:
INFLUENCE OF 10" (254mm) OF RAIN ACCUMULATED ON CENTER DECK
10" Rain
For deck to support 10" (254mm) of rain water: Volume of rain water collected at the deck, Vrain = Adeck x Hrain where Adeck = Hrain =
=
233.99
m³
π /4 x Øir 2 Area of deck = Rain accumulation of 10"
Vol. rain x ρ
rain
= 921,213,536.64 mm³ = 254 mm = 233,988.24 kg
Weight of 10" accumulated rain water, Wrain =
Upward Bouyant Load = Deck Area x Floatation Height x Product density = π /4 x (Øir) 2 x H (rain) x ρ Downward load due to deck steel and rain water, = W deck + W rain Nett downward force acting on deck = (Upward bouyant load - Downward Load) = Deck Area
=
242,429.27 kg
=
291,840.45 kg
75
=
53.64
kg/m2
qα Et
4 4
= K
1
y + K t
2
y t
3
( 11.11.1)
σα
Et
Where: t= α= q= y= σb = σd = σ= v= E=
2 2
= K
3
y + K t
4
y t
2
( 11.11.2)
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/mm2
0.3 200,000 N/mm²
The deck plate is fixed and held at its outer edge by the pontoon, hence condition is consider as: Case 3 Fixed and Held. Uniform pressure q over entire plate K1 = K2 = At the Centre, K3 = K4 At the edge, K3 = K4 For 4 1 - ν2 = =
4
5.33 1 - ν2 2.6 1 - ν2
K 3 = 2 1 − v
=
5.86
=
2.86
2 1- ν
= =
2.86 0.976
4.40 1.73 55,228.70
qα Et4 y t
=
And
K1
+ K2
y
y t
3
= =
q α4 Et4 214.38325 mm
=
55,140.73
Solving equation 11.11.2 σα² E. t 2 = K3 y t = = At Deck Center, + K4 777.4581306 1360.154003 y t 2
(at Deck Center) (at Deck Edge)
2 33.94 N/mm 2 3.34 N/mm 2 30.60 N/mm
σtotal σbending σdiaphgram
At Deck edge,
= = =
σtotal σbending σdiaphgram
= = =
2 59.37 N/mm 3 5.14 N/mm 4 54.23 N/mm
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
PONTOON STRESS DESIGN - CASE 2 PONTOON PROPERTIES Nominal diameter of Inner Rim, Øir Section modulus available, Za2 = Cross sectional area, Aa
= = =
34248 mm 27019626.01 mm3 49,176 mm²
10 .4.2
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 PONTOON RING DESIGN
: SA 516 Gr. 65N = 275.00 N/mm² = 1.000 = 1.00 = 183.33 N/mm² = 165.00 N/mm²
10 .4.3
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, Rh.Do Mm = 4 At Reaction-Point, Bending moment, Rh.Do Mr = 4 10 .4.4 RESULT RING STABILITY CHECK Bending Moment Circumferential force Bending Stress Circumferential stress Allow. bending stress Allow. axial stress Unity Check Condition ( Nmm ) (N) ( N/mm² ) ( N/mm² ) ( N/mm² ) ( N/mm² ) MID-POINT 18.08 7,429,209 0.0000007 151.07 183 165 0.92 OK. LOAD-POINT -36.15 7,429,209 -0.000001 151.07 183 165 0.92 OK. α 1 tan α 1 Tr = 2 tan α sin α 1 α 1 Tm = 2.sin α
Circ. tensile force, Rh
Circ. tensile force, Rh
10 .4.5
STRESSES SUMMARY LOAD CASE 1 Deck Center Deck Edge 35.92 62.84 3.52 32.40 5.41 57.43 LOAD CASE 2 Deck Center Deck Edge 33.94 59.37 3.34 30.60 5.14 54.23
σtotal ( N/mm² ) σbending ( N/mm² ) σdiaphgram ( N/mm² )
11 .0
ROOF SUPPORT LEG DESIGN 22 15 10 5 Nos. at R4 Nos. at R3 Nos. at R2 Nos. at R1 18541.00 13716.00 8839.00 4267.00
11 .1
GEOMETRIC DATA Support leg size Pipe outside diameter Pipe Thickness, Pipe Area, Aleg Radius of gyration, r = I Aleg Do2 - Di2 4 = 3" Sch. 80 = 88.9 = 7.62 = 1,945.76 = 24.89 mm mm mm2
11 .2
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 : Deck O.D Deck Thickness, td Deck Area, Adeck Center deck weight, Wdeck Design Live Load, Llive Effective radius for area of deck supported by leg: R3eff =
: SA 333 Gr 6 = 241 N/mm² 209,000 N/mm² = = 7,850 kg/m³
11 .3
Lsp1 Lsp2 Lsp3 Lsp4
= = = =
2927 2927 2927 2940
mm mm mm mm
= 34231 =8
mm mm 2 = 920,299,220.87 mm = 57,794.79 kg KN/m2
= 1.2
1/2(Øir/2-R3) = 15415.75 R2eff = 1/2(R3-R2) = 11277.5 R1eff= 1/2(R2-R1) = 6553
Area of deck supported by legs at i) ii) iii) iv) R1 = π(R1eff)2 R2 = π((R2eff) - (R1eff) ) R3 = π((R3eff) - (R2eff) ) R4 = p((Ødeck) - (R3eff) )
2 2 2 2 2 2 2 = 134,905,671.69 mm 2 = 264,648,384.82 mm 2 = 347,030,823.13 mm 2 = 173,714,341.24 mm
11 .4
SUPPORT LEG AT INNER DECK R1 No. of legs at R1 Area of deck supported by legs at R1, A1 Deck area on each leg, A1' Deck load on one leg = Live load on one leg = Total load on one leg = Wdeck x A1' Adeck
= = = = = = Total Load / Aleg =
5 26,981,134.34 mm2 1,694.42 kg 16.62 KN 32.38 KN 49.00 KN
2 25.18 N/mm
= 134,905,671.69 mm2
Llive x A1' Deck load + Live load
Stress on support leg at inner deck R1, P1 = 11 .4.1
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 < Sc.all, the support leg at inner deck R1 is satisfactory.
= =
118 1
=
130.84
=
75.08 N/mm²
=
77.80 N/mm²
= =
74.20 N/mm² 75.08 N/mm²
11 .5
SUPPORT LEG AT INNER DECK R2 No. of legs at R2 Area of deck supported by legs at R2, A2 Deck area on each leg, A2' Deck load on one leg = Live load on one leg = Total load on one leg = Wdeck x A2' Adeck
= = = = = = =
10 26,464,838.48 mm2 1,661.99 kg 16.30 KN 31.76 KN 48.06 KN
2 24.70 N/mm
= 264,648,384.82 mm2
Llive x A2' Deck load + Live load
Stresses on support leg at inner deck R2, P2 = 11 .5.1 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
= =
118 1
=
130.84
When λ ≤ Cc, [ 1 - λ² / 2Cc² ].Sy Sc.all = (i) = 75.08 N/mm² 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 <
(ii)
=
77.80 N/mm²
= = satisfactory.
74.20 N/mm² 75.08 N/mm²
Sc.all, the support leg at inner deck R2 is
SUPPORT LEG AT INNER DECK R3 No. of legs at R3 Area of deck supported by legs at R3, A3 Deck area on each leg, A3' Deck load on one leg = Live load on one leg = Total load on one leg = Wdeck x A3' Adeck
= = = = = = Total Load / Aleg =
15 23,135,388.21 mm2 1,452.90 kg 14.25 KN 27.76 KN 42.02 KN
2 21.59 N/mm
= 347,030,823.13 mm2
Llive x A3' Deck load + Live load
Stresses on support leg at inner deck R3, P3 = 11 .6.1
ALLOWABLE STRESS As per AISC code, Slenderness ratio, λ = K.Lsp3 / 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 P3 < Sc.all, the support leg at inner deck R3 is
= =
118 1
=
130.84
=
75.08 N/mm²
=
77.80 N/mm²
= = satisfactory.
74.20 N/mm² 75.08 N/mm²
11 .7
SUPPORT LEG AT PONTOON No. of legs at R4 Area of deck supported by legs at R4, A4 Deck area on each leg, A4' Deck load on one leg = Wdeck x A4' Adeck
= = = = = = = = = =
27 6,433,864.49 mm2 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
= 173,714,341.24 mm2
Pontoon weight, Wpontoon Pontoon weight on one leg, Wpontoon' Live load on one leg = Total load on one leg = Llive x A4' Deck load + Live load + Pontoon weight Total Load / Aleg
Stresses on support leg at Pontoon, P4 = 11 .7.1
ALLOWABLE STRESS As per AISC code, Slenderness ratio, λ = K.Lsp4 / 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 P3 < Sc.all, the support leg at inner deck R3 is
= =
118 1
=
130.84
=
74.62 N/mm²
=
77.12 N/mm²
= = satisfactory.
73.93 N/mm² 74.62 N/mm²
11 .8
STRESSES SUMMARY Actual stress, (N/mm2) 25.18 24.70 21.59 31.33 Allowable stress, (N/mm2) 75.08 75.08 75.08 74.62
Leg at radius 4267.00 8839.00 13716.00 18541.00
No. of leg 5.00 10.00 15.00 22.00
RESULT OK OK OK OK
12 .0 12 .1
BLEEDER VENT CALCULATION 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 OPERATING VENTING NORMAL VACUUM VENTING Maximum liquid movement out of a tank Flow rate of free air, Vv1 ( = Vo/15.9 x 15.89 )
FP
)
: API STD 2000 = 39000 = 20700 24000 = 2.50 = 67 = 427 = 1,100
mm mm m³ mbarg °C m³/hr m³/hr
12 .2 12 .2.1
=
1097.23 m³/hr
12 .2.2
Thermal inbreathing Tank capacity, V From Table 2, column 2 (Thermal Venting Capacity Req't ), Flow rate of free air,Vv2 (@ 0 ft³/hr ) Total vacuum flow required, Vv ( = Vv1 + Vv2 )
= = =
155,535 barrels 0 m³/hr 1,097 m³/hr
12 .3 12 .3.1
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 ) 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 ) OPEN VENT SIZING ( BLEEDER VENT SIZING ) OPEN VENT SIZING CALCULATION Maximum flow, Q ( @ Vacuum flow at ( @ Q= where K= A= g= H= K. A. 2. g. H Discharge coefficient cross sectional area of vent acceleration due to gravity Head as measure pressure differential Dp H= g
= =
0.17 m³/hr 457 m³/hr
12 .3.2
= =
0 m³/hr 457 m³/hr
12 .4
2.50
mbarg. )
=
1,097 m³/hr
0.62
=
21 m
Minimum require cross sectional area of vent, Av_req = where Q= g= r= Dp = 12 .5 Q K. 2. g. H = Q K g 2. g. Dp = = = =rg = = = 0.0241 m² 24,124 mm² 0.3048 mm³/s 11.812 kg/m2s2 1.204 kg/m³ 250 N/m²
Max. Air flow required Specific weight of Air Air density Differential pressure
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, Av_actual Since Av_actual > Ar_gnv, therefore the nos. & size of vents is
: =
8" Sch Std 1 219 = 202.64 mm = 32,251 mm² satisfactory.
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 Roof Deck Area Design Rain Fall Design drainage required, Qreq. No. of Roof Drain, N Roof drain pipe size (rigid & fitting) Dain Pipe Outside Diameter, Do Drain pipe thickness Drain Pipe length : L1 = Rigid L2 = Flexible 13 .2 = = = = = = = = = = = 39,000 20,100 1500 225 mm mm mm mm
920.30 m2 50 mm/hr 46.01 m3/ hr 2 4" Sch 80 101.6 mm 8.56 mm
20 m x 23.14 m x
2 1
nos. nos.
= =
40 m 23.14 m
Number of Fitting & Accessories per drain pipe - 45º elbow 90º elbow Valve Rigid pipe Flexible pipe
N45º N90º Nv
= = = = =
2 1 1 2 1
13 .3
TOTAL HEAD H = h+ V2 2g
13 .4
TOTAL HEAD LOSS OF ROOF DRAIN PIPE V2 x 2g K L' D
h= Where H = G = K =
L' = D = 13 .5
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
m
K1 K2
= 0.0168 = 0.03 = 0.08448 m
EQUIVALENT PIPE LENGTH OF VALVE AND FITTING Accordance to NFPA 15 Table 8.5.2.1, 45º elbow, L45º Equivalent length for 4" 90º elbow, L90º Valve, Lv Total equivalent pipe length for RIGID PIPE: L1' = L1 + N45º x L45º + N90º x L90º + Nv x Lv Total equivalent pipe length for Flexible PIPE: L2' = L2
= = =
3.1 1.2 0.6
=
48 m
=
23.14 m
13 .6
TOTAL HEAD LOSS OF ROOF DRAIN PIPE h= H= H= V2 2g K1 L1' D + K2 L2' + 1 D V2 x 2g K1 L1' D + K2 L2' D
13 .7
FLOW VELOCITY 2gH V= K1 L1' D + K2 L2' + 1 D = 1.15 m/s
13 .8
DRAINAGE FLOW RATE PER DRAIN PIPE Q = AREA x Velocity = π/4 x D2 x V x 3600 (s/hr) = 23.30 m3 / hr
13 .9
MINIMUM ROOF DRAIN REQUIRED Drainage flow rate required Nreq = Actual flow rate per drain MINIMUM REQUIRED
= = 2
1.97
14
WEIGHT ANALYSIS ITEM NO : 7061T-3901
1 GENERAL Design code : API 650 11th Edition Inside diameter : 39,000 mm Steel density Shell / Btm : 7,850 kg/m³ Roof : 8,027 kg/m³ 2 SHELL COURSES ONE - FOOT METHOD (OUTER TANK) Course No. Material 1 2 3 4 5 6 7 8 9 10 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 -
Type of roof support : NA Tank height : 20,700 Roof plates lapping factor : 20.70
Type of roof : Floating Roof mm Annular/Bottom plates lapping factor : 1
Y Thickness (mm) 28.00 25.00 22.00 19.00 16.00 13.00 11.00 11.00 11.00 Width (mm) 2,440 2,440 2,440 2,440 2,440 2,440 2,020 2,020 2,020 Weight (kg) 65,757 58,707 51,658 44,611 37,564 30,518 21,377 21,377 21,377 352,948 kg
Total weight of shell plates = 3 BOTTOM PLATES Material A 516 GR. 65N 4 TOP CURB ANGLE Material A 516 GR. 65N 5 TOP WIND GIRDERS Material A 516 GR. 65N Y Thickness (mm) 9.00 Outside Dia. (mm) 39,130 Y Size 76 x 76 x 6.4 Qty 1 Length (mm) 122,827 Unit Weight (kg/m) 10.33 Y Size Qty 1 Length (mm) 125,183 Unit Weight (kg/m) 87.51 Y Qty 1 Length (mm) 124,476 Unit Weight (kg/m) 53.76 Y 1,500 Y 5.00 % of total weight Y 16,820 = 22,916 = = Weight (kg) 6,691 Weight (kg) 10,955 Weight (kg) 1,269 Weight (kg) 84,961
=
84,961 kg
=
1,269 kg
T 825 x 250 x 8 x 10
=
10,955 kg
6 INTERMEDIATE WIND GIRDERS Material Size A 516 GR. 65N 7 NOZZLES Total weight of nozzles 8 MISCELLANEOUS Assuming T 405 x 150
=
6,691 kg
1,500 kg
22,916 kg
9 STAIRWAY & PERIMETER PLATFORM Platform Weight 165.00 KN 10 OPERATING LIQUID WEIGHT Operating liquid height 11 HYDROSTATIC WATER WEIGHT Hydrostatic water height ERECTION WEIGHT (Exclude roof) OPERATING WEIGHT FIELD HYDROSTATIC TEST WEIGHT
16,820 kg
(@ =
20,700
mm & sg @=
1.00 )
=
24,728,026 kg
(@
20,700
mm )
= = = =
24,728,026 kg 498,060 kg 25,226,086 kg 25,226,086 kg
STORAGE TANK DESIGN CALCULATION - API 650 1 .0 DESIGN CODE & SPECIFICATION DESIGN CODE TANK Item number Roof ( Open/Close ) Type of roof ( Cone-roof / Dome-roof / Flat-roof / NA ) 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 MATERIAL & MECHANICAL PROPERTIES Component Material Tensile Stress St(N/mm²) 448.00 448.00 448.00 448.00 448.00 448.00 448.00 448.00 Yield Stress Sy(N/mm²) 241.00 241.00 241.00 241.00 241.00 241.00 241.00 241.00 Corrosion Allowance c.a.(mm) 3.000 3.000 3.000 3.000 3.000 3.00 3.00 3.00
: API 650 11th Edition
1 .1
: 7061T-3901 : Close : Floating Roof
1 .2
= = = = = = = =
39,006 39,028 39,031 20,700 0.790 1.00 24736 20,700
mm mm mm mm
m³ mm
1 .3
(Atmospheric) = = = =
0.00 0.00 70 -17
mbarg mbarg Vac °C °C
1 .4
PLATE Shell Plate
( Mat'l Code # 1 ) (bot) ( Mat'l Code # 2 ) (top)
Annular Plate Bottom Plate Roof Plate STRUCTURE MEMBERS Roof structure (rafter,bracing,etc ) Top Curb Angle Intermediate Wind Girder
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 .0 2 .1
SHELL THICKNESS CALCULATION BY ONE-FOOT METHOD SHELL DESIGN GEOMETRIC DATA Plate size used PTS 34.51.01.31 clause 6.3 Shell plate min. width as per MATERIAL & MECHANICAL PROPERTIES Material used Specified Specified Yield stress Max. allow Max. allow min. tensile min. yield reduction fac design hydro.test stress stress ( App. M ) stress stress St (N/mm²) Sy (Nmm²) k Sd (N/mm²) St (N/mm²) 448.00 448.00 448.00 448.00 448.00 448.00 448.00 448.00 448.00 241.00 241.00 241.00 241.00 241.00 241.00 241.00 241.00 241.00 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 1.000 160.67 160.67 160.67 160.67 160.67 160.67 160.67 160.67 160.67 180.75 180.75 180.75 180.75 180.75 180.75 180.75 180.75 180.75 -
: :
2,440 mm 1,500 mm
2 .2 No
Corrosion allowance c.a (mm) 3.00 3.00 3.00 3.00 3.00 3.00 3.00 3.00 3.00 -
1 2 3 4 5 6 7 8 9 10
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 .3
SPECIFIED MINIMUM SHELL THICKNESS Specification Minimum thickness as per API 650 cl 5.6.1.1 PTS 34.51.01.31 Minimum thickness as per
: API 650 11th Edition = 8.00 mm = 11.00 mm
2 .4
SHELL THICKNESS CALCULATION BY ONE-FOOT METHOD ( CLAUSE 5.6.3.1 ) 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
t.min = Min. of t.design, t.hydo & min. thickness as per PTS. tsc = Thicknes selected & used
2 .5 No. Mat'l Code No. 1 2 3 4 5 6 7 8 9 1 1 1 1 1 1 1 1 1
CALCULATION & RESULTS Material Width (mm) Height (mm) t.design (mm) t.hydro. (mm) t.min (mm) tsc. (mm) Result
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
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 No.
MAXIMUM ALLOWABLE STRESS 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 H' = H' max = P'max = Pmax =
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
Effective liquid head at design pressure Max. liquid head for tsc. Max. allowable stress for tsc. Max. allowable stress at shell course.
3 .0
BOTTOM & ANNULAR PLATE DESIGN 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
= = satisfactory. == = =
6.00 mm 9.00 mm
Min. width of overlapping (cl. 5.1.3.5) Min. width of plate (cl. 5.4.1) -
mm 25 mm 1800 mm 50 mm
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 Annular plate thickness ( As per Table 5-1a ) Minimum thickness required (@ 3.00 16.00 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
mm c.a. ) mm (ta) is
satisfactory. = = = = = = = 13.00 mm 600 mm 756.09 mm 16.000 mm 20.70 m 1.00 50 mm
(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 = (HL. SG )0.5 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)
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.
1000 mm
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 Section modulus, Za Since Za 4 .1.2 > Zmin , therefore the angle size selected is
= =
76 x 76 x 6.4 8380 mm3
= 75 x 75x 10 = satisfactory. 13500 mm
3
TOP WIND GIRDER The required minimum section modulus of the stiffening ring shall be as follows:Z= where Dc H2 V Dc².H2 17 V 190
2
= = = = =
1007 cm³ 1,007,140 mm³ 39.031 m 20.7 m 140.00 km/hr
= 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 X 2 8 250 mm 1 X 825 mm L1=16.tsc.cor C1 D= 39037
: T 825 x 250 x 8 x 10 = 825 mm = 250 mm = 8 mm = 10 mm = 8.00 mm
mm
=
128
mm
3
A Y AY h (mm²) (mm) (mm³) (mm) 1 2048 4.00 8192 433.61141 2 6600 420.5 2775300 17.1114101 3 2,500 838.00 2,095,000 400.39 TOTAL 11,148 4,878,492 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
A.h² (mm4) 385062615 1932482.35 400,777,557 787,772,655
I = (bd³)/12 (mm4) 10,923 374343750 20,833 374,375,506 = 438 mm = 1,162,148,161 mm4 = 2,655,662 mm³ satisfactory.
5 .0 5 .1
INTERMEDIATE WIND GIRDERS CALCULATION INTERMEDIATE WIND GIRDERS DESIGN MAXIMUM HEIGHT OF THE UNSTIFFENED SHELL ( CLAUSE 5.9.7.1 )
SI METRIC UNIT :H1 = (9.47 ts.cor) where ts.cor Dc
3
x
190 ² V
= = = = =
9.182 m 9182 mm 8.00 mm 39.03 m 140.00 km/hr
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 5 13.00 2,440 725 6 10.00 2,440 1,397 7 8.00 2,020 2,020 8 8.00 2,020 2,020 9 8.00 2,020 2,020 10 11 12 13 14 15 Height of transformed shell, H2 = 9,230 mm
5 .2
Since H1 < H2, therefore the intermediate required wind girder is/are Minimum number of intermediate wind girders required, = 1 Location of intermediate wind girders from top of tank, L1 = 4615 mm L2 = - mm L3 = - mm - mm L4 = L5 = - 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 :Z.min = 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 X 2 8 150 mm 1 X 450 mm L1=16.tsc.cor = 128 mm C1 D= 39037 = = = 39.031 m 4.615 m 140.40 km/hr Dc². H1 17 V 190
2
= =
225.812 cm³ 225,812.032 mm³
: T 405 x 150 = 450 = 150 8 = = 8 = 8.00
mm mm mm mm mm
mm
3
A Y AY h (mm²) (mm) (mm³) (mm) 1 2048 4.00 8192 200.642523 2 3600 233 838800 28.3574766 3 1,200 462.00 554,400 257.36 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
A.h² (mm4) 82447200.6 2894927.33 79,479,445 164,821,573
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) WIND 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 ), WDL (@ 550,045 327,512 kg ) kg )
= = = = = = = = = = = =
0 N/mm² 75 mm 39,000 20,700 0.000 0 10,350 20,700 0 mm mm ° mm mm mm mm
5,395,939 N 0N 3,212,898 N
6 .2
WIND FORCE CALCULATION As per API 650 clause 5.2.1(j), the wind pressure are as follows:30.00 Wind pressure on conical surfaces, wr (@ Wind pressure on cylindrical surfaces, ws (@ 18.00 Wind correction factor, kw (= V /190)² Projected area of roof, Ar ( = 0.5.k.Do.Hr ) Projected area of shell, As ( = k.Do.Hs ) 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, Mw ( = Fr.Lr + Fs.Ls )
psf ) psf )
= = = = = = = =
0.0014369 N/mm² 0.0008621 N/mm² 1.00 0 mm² 811,564,200 mm² 0N 699,681 N 7,241,700,964 Nmm
6 .3
OVERTURNING STABILITY AGAINST WIND LOADING Wind Uplift Load
Internal Pressure Load D/2
Wind load on shell, Fr H/2
H
Momment about shell to bottom joint Dead Load (WDL)
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
=
0 Nmm
Overturning moment about the shell-to-bottom joint from horizontal
= 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 shell. 0.5. D. WDL Weight of roof = 0,since it is floating on liquid Moment about the shell-to-bottom joint from liquid weight (wa) (wa. π D). D 1000 2 Weight of liquid = 59 tb Fby. H Design liquid height Thickness of Bottom plate under the shell Minimum specified yeid stress of the bottom plate under the shell 0.6 Mw + Mpi < MDL / 1.5
=
7,241,700,964 Nmm
= 62,651,502,376 Nmm
MF = =
= 153,419,379,181 Nmm
wa = H= tb = Fby =
= = = =
64,214.21 N/m 19.2 m 16 mm
2 241 N/mm
FOR CRITERIA 1 0.6 Mw + Mpi MDL / 1.5 FOR CRITERIA 2 Mw + 0.4 Mpi (MDL +MF) / 2 Since, 0.6 Mw + Mpi Mw +0.4 Mpi
= 4,345,020,578 Nmm = 41,767,668,251 Nmm Mw + 0.4 Mpi < (MDL +MF) / 2 = 7,241,700,964 Nmm = 108,035,440,779 Nmm
< <
MDL/1.5, and 1/2 (MDL+ MF)
The tank anchorage is NOT REQUIRED.
7 .0 7 .1 7 .1.1
SEISMIC FORCE CALCULATION SEISMIC LOADS DESIGN GEOMETRIC DATA Seismic peak ground acceleration, Sp Importance factor, I Site Class Seismic Use Group, SUG 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 Total weight of tank shell, Ws Total weight of tank roof, Wr Total weight of tank contents, Wp Total weight of tank bottom, Wf (@ (@ (@ (@ 352,948 0 24,728,026 84,961 kg ) kg ) kg ) kg )
= = = = = = = = = = = = = =
0.3 g 1.50 D III 39,031 20,700 10,350 20,700 0 1 3,462,418 0 242,581,931 833,471 mm mm mm mm mm
N N N N
7 .1.2
Note: The total weight of the tank roof will be added to the weight of tank content, since the roof is floating on the liquid. DESIGN SPECTRAL RESPONSE ACCELERATIONS Impulsive spectral acceleration parameter, Ai Ai = 2.5 Q Fa So I Rwi = 0.34
Convective spectral acceleration parameter, Ac When Tc ≤ TL Ac = 2.5 K Q Fa So Ts Tc I Rwc ≤ Ai = -
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
≤ Ai
=
0.063298299
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
sloshing period coefficient 0.578
Ks =
tanh
3.68 H D
=
0.59
Ts = where, Fa = Fv = S1 = Ss =
Fv . S1 Fa . Ss
=
0.69
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
= =
1.2 1.6500
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 = For D/H < 1.333, Wi = Since 1.0 - 0.218 D H . Wp tanh (0.866.D/H) 0.866. D/H . Wp
= = = =
0.375 0.75 0.06 0.34
= 137,636,499.10 N
=
-
N
D/H > 1.333 , effective impulsive portion of the liquid weight, Wi
= 137,636,499.10 N
Effective convective weight, Wc = 0.230 D H tanh 3.67H D . Wp = 100,998,137.14 N
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, Xi = For D/H < 1.333, Xi = Since 0.5 - 0.094 D .H H = = mm 0.375H = 7762.5 mm
D/H > 1.333 , Xi
7,762.50 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, cosh Xc = 1.0 3.67H D 3.67 H D sinh -1 3.67 H D .H = 12,722.55 mm
7 .2.3
OVERTURNING MOMENT The seismic overturning moment at the base of the tank shell shall be the SRSS summation of the impulsive and convective components multiplied by the respective moment arms to the center of action of the forces. Ringwall moment, Mrw = [Ai ( Wi. Xi + Ws. Xs + Wr. Xr)]
2
+ [Ac (Wc. Xc)]
2
= =
3.81453E+11 Nmm 381453029.8 Nm
7 .2.4
SHEAR FORCE The seismic base shear shall be defined as the SRSS combination of the impulsive and convective components. V= where, Vi2 + Vc2 Vi = Vc = Ai (Ws + Wr +Wf + Wi) Ac. Wc = = = 48,326,902.75 N 47,902,181.05 N 6,393,010.26 N
7 .3 7 .3.1
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 Anchorage Ratio, J J= where, Av = Wt = wa = Mrw D2 ( Wt (1 - 0.4 Av) + Wa ) = = =
16.00 mm 28.00 mm 1200.0 mm 241.0 N/mm 2 241.0 N/mm
2
2.17
Vertical earthquake acceleration coefficient Tank and roof weight acting at base of shell Resisting force of the annulus
= = =
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)
=
28.24 N/mm
=
0 N/mm
The resisting force of the annulus, wa = 99 ta Fy. H. Ge wa < 196.H.D.Ge =
≤ 196. H. D. Ge 114,016,732,704.00
=
94,932.54 N/m
Ge = Effective specific gravity including vertical seismic effect = G. (1 - 0.4 Av)
=
0.72
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= 0.01723 ta Fy H. Ge = = = 1,108.57 mm 1,366.09 mm 1,108.57 mm
The maximum width of annulus for determining the resisting force, 0.035 D Since L And, Since Ls 7 .3.3 < > 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 = wt ( 1 + 0.4 Av) + 1.273 Mrw D
2
1 ts = 12.67 N/mm
7 .3.4
MAXIMUM ALLOWABLE SHELL COMPRESSION A= GHD² ts² ( D in m ) = 40.223 m³/mm²
For GHD²/(ts²) < 44 m³/mm², Fc = 83.ts 2.5D + 7.5{G.H}½
=
57.94 N/mm²
For GHD²/(ts²) ≥ 44 m³/mm², Fc = 83.ts D = N/mm²
Therefore, Fa ( < 0.5Fty ) Since σc < Fc, therefore the tank is structurally stable.
=
57.94 N/mm²
7 .4
FREE BOARD FOR SLOSHING WAVE HEIGHT Sloshing wave height above the product design height, δs = 0.5 D. Af where: For SUG I and II, When Tc ≤ 4 Af = When Tc > 4 Af = For SUG III When Tc ≤ TL Af = When Tc > TL Af = Since SUG is K. SD1 III TL Tc and
2
=
1,647.06 mm
K. SD1. I.
1 Tc
=
2.5 K Q Fa So I
Ts Tc
=
0.21
K. SD1. I.
4 Tc
2
=
2.5 K Q Fa So I
4Ts Tc
2
=
0.13
K. SD1
1 Tc
=
2.5 K Q Fa So
Ts Tc
=
0.14
=
2.5 K Q Fa So Tc > TL
Ts. TL Tc , Af
2
= =
0.08 0.08
For SDS = 0.9 Q Fa Ss = Minimum required freeboard, δsreq 7 .5 7 .5.1 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
> 0.33g, ( as per Table E-7)
=
1,647.06 mm
3.000
= = mm) (min.size.25.4 mm ) = = = =
86 64 58 39,320 2,642 1,436
mm mm mm mm² mm
7 .5.2
MATERIAL & MECHANICAL PROPERTIES Material used Specific minimum yield stress, Sy Allowable tensile strength, St.all ( 0.80Sy ) ( Table 5-21a ) Uplift force due to seismic loading, W AB = where Mrw = Dc = wt = Av = wint = 1.273 Mrw Dc² - wt ( 1 - 0.4 Av) + wint
: = =
SA 320 Gr L7 551.5 N/mm² 441.20 N/mm²
=
36,592,019 N
Overturing moment due to seismic Nominal diameter of tank Tank and roof weight acting at base of shell, Vertical earthquake acceleration coefficient Uplift thrust due to internal pressure
= = = = =
3.81453E+11 39,031 28.24 0.70 0
Nmm mm N/mm N/mm
Tensile stress, σb = WAB / N.Ab Since σb < St.all,therefore the anchor bolt size is satisfactory.
=
161.04 N/mm²
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
Inner Rim
Outer Rim
15
975
Post
525
Btm Angle Bulkhead Deck Plate
8
198
2181 38610
Shell I.D
34248
39006 ( All dimensions in mm unless otherwise stated. )
8 .1
TANK GEOMETRY DATA Inside diameter , Di ( corroded ) (@ Tank height (tan/tan), H Material of Construction Specific Minimum Yield Stress, Sy Modulus of Elasticity Density of Material, ρ (plate) Corrosion Allowance Min. Specific Gravity of product Max. Specific Gravity of product
39,000
mm )
= =
39,006 mm
: SA 516 Gr 65N = 275 N/mm² 209,000 N/mm² = = 7,850 kg/m³ = = = 3 mm 0.7 1
8 .2
GEOMETRY DATA Outer Rim Height, Hor Inner Rim Height, Hir Pontoon width, w Rim Gap Outer Rim Extend above pontoon, Hext No. of Pontoons, N Outer Rim Diameter, Øor Inner Rim Diameter, Øir Bulkhead Outer heigh, Boh Bulkhead Inner heigh, Bih Bulkhead Width, wb
= = = = = = = = = = =
975 525 2181 198 75 22
mm mm mm mm mm
38610 mm 34248 mm 884 mm 509 mm 2157 mm
8 .3
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
= = = = = = =
9 15 8 8 8 8 8
mm mm mm mm mm mm mm
6.85 kg/m 6.85 kg/m
8 .4 8 .4.1
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 WEIGHT CALCULATION Top Pontoon Bottom Pontoon Inner Rim Outer Rim Bulkheads Deck Plate =
= @ unit wt @ unit wt = =
22 15.27 22.32 2940 1084
kg/m kg/m mm mm
8 .4.2
(Area od deck / 30m² / leg ) 3" pipe x Sch. 80 4" pipe x Sch. 80
= @ unit wt @ unit wt = =
30 15.27 22.32 2927 823
kg/m kg/m mm mm
8 .5
π /4 x( Øor² - Øir²) x Ttp x ρ (plate) π /4 x( Øor² - Øir²) x Tbp x ρ (plate) π x Øir x Hir x Tir x ρ π x Øor x Hor x Tor x ρ
1/2 x (Boh - Bih)x wb x Tb x ρ x N
= = = = = = = = = =
15,675.18 kg 15,675.18 kg 6,651.28 kg 8,355.38 kg 2,075.65 kg 57,852.21 kg 987.66 532.29 1340.86 551.08 kg kg kg kg
= = = =
π /4 x Øir x Td x ρ
Pontoon Legs Pontoon Legs housing Deck Legs Deck Legs housing TOTAL WEIGHT Pontoon Components: (Wpontoon) Deck Components: (Wdeck) Total Weight of Floating Roof, (Wroof)
= = =
55,248.45 kg 57,852.21 kg 113,100.66 kg
9 .0
PONTOON VOLUME O. Rim Ø I. Rim Ø + 2 x 2/3 w h3 = 0.03 3 I. Rim Ø h2 = 0.53 h1 = 0.35 1 2 Volume 1 Volume 2 Volume 3 Total Pontoon Volume, Vol(pontoon) = = = = 40.70 m³ 120.17 m³ 3.85 m³ 164.72 m³ 2 34248 mm 38610 mm 37156 mm
9 .0 9 .1
SETTING DECK LEVEL OPERATION FLOATATION LEVEL - DECK Deck Floatation Depth Deck Thk Floatation Depth, D(deck) = = Density of Deck Density of Product
ρ (deck) ρ (product)
x Td
=
89.71 mm
9 .2
OPERATION FLOATATION LEVEL - PONTOON Buoyant Force, FB ρ x Vdisplacement x g = = Fpontoon W (Pontoon) x g Pontoon Weight, W(pontoon) ρ (product) = 78.93 m³
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) = 153.15 mm
D(pontoon) =
3 2 153.15 1 The Deck is set at the difference of floation depth in Pontoon & Deck, D(deck) - D(pontoon) 9 .3 = 63.44 mm 89.71
Freeboard above deck, 494.56 Product Level Deck Level 63.44 mm
NORMAL OPERATION FLOATATION LEVEL FOR ROOF - PONTOON & DECK
Actual Product Level Deck Level
161.57 m³ Deck
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
=
40.70
ii)
Partial Volume Displaced in Pontoon below the deck level: Deck level Height, h Bulk head outer height, Bih x Vol. 2 = 14.98 m³
iii)
Volume Displaced by the Deck: Area of Deck Plate x Floatation Height Above Deck π /4 x Øir 2 x H
= =
921.21 H 0.11 m 114.95 mm
Hence, The Floatation Height Above Deck, H
94
FLOATATION LEVEL FOR ROOF - PONTOON & DECK FOR 10" (254MM) OF ACCUMULATED RAIN WATER For deck to support 10" (254mm) of rain water: Volume of rain water collected at the deck, Vrain = Vrain = Adeck x Hrain where Adeck = Hrain =
=
233.99
m³
π /4 x Øir 2 Area of deck = Rain accumulation of 10"
2 = 921,213,536.64 mm = 254.00 mm
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) = Wt(rain) = Total weight of roof Weight of 10" rain water
m³
Floatation Height above Deck, H(rain) = Vdisplacement (rain) - Vol.1 - partial of Vol.2 (ii) Area of roof 10 0 10 1 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
= =
0.38 m 375.95 mm
qα Et
4 4
= K
1
y + K t
2
y t
3
( 11.11.1)
σα
Et
Where: t= α= q= = y= σb = σd = σ= v= E=
2 2
= K
3
y + K t
4
y t
2
( 11.11.2)
Plate thickness, Deck (mm) = Td = Outer radius of the deck plate = Øir / 2 = Unit lateral pressure (equiv. weight of deck that float on product)
8 17124 N/mm2
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
N/mm²
The deck plate is fixed and held at its outer edge by the pontoon, hence condition is consider as: Fixed and Held. Uniform pressure q over entire plate (Case 3 in Roark's Formulas) K1 = K2 = At the Centre, K3 = K4 At the edge, K3 = K4 For 4 1 - ν2 = = = 4.40 1.73 56,361.13 2 1- ν = = 2.86 0.976 5.33 1 - ν2 2.6 1 - ν2 = = 5.86 2.86
q α4 Et4
3
And
K1
y t
+ K2
y
y t
= =
q α4 Et4 215.81 mm
=
56,249.31
Solving equation 11.11.2 σα² E. t 2 = K3 y t = = At Deck Center, + K4 787.3494954 1377.567315 y t 2
(at Deck Center) (at Deck Edge)
2 35.92 N/mm 2 N/mm 3.52 2 32.40 N/mm
σtotal σbending σdiaphgram
At Deck Edge,
= = =
σtotal σbending σdiaphgram
= = =
2 62.84 N/mm 2 5.41 N/mm 2 57.43 N/mm
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 =
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 2160 12 9 8 8 mm mm mm mm
2 2160 525 4 900 α 2187 3
Top Pontoon slope angle @ 1 : 64 = Backslope angle, α = A Y (mm²) (mm) 1 6300 6 2 17282 1092 3 17494 1092 4 8100 2176.5 TOTAL 49,176 Neutral axis of combined section, C1 Moment of inertia of section , Ix-x Section modulus available, Za 10 .2.2 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 AY (mm³) 37,800 18,872,063 19,103,800 17,629,650 55,643,313 h (mm) 1,126 40 40 1,045
0.02 rad 0.16 rad
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 = = 30,572,806,264 mm4 27,019,626 mm³
: SA 516 Gr. 65N = 275.00 N/mm² = 1.000 = 1.00 = 183.33 N/mm² = 165.00 N/mm²
10 .2.3
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, Rh.Do Mm = 4 At Reaction-Point, Bending moment, Rh.Do Mr =1 1 Tr = 2 tan α sin α 1 α 1 Tm = 2.sin α
Circ. tensile force, Rh
Circ. tensile force, Rh
4 α tan α ( Do= Qir, nonimial diamter of inner ring)
10 .2.4
RESULT RING STABILITY CHECK Bending Moment Circumferential force Bending Stress Circumferential stress Allow. bending stress Allow. axial stress Unity Check Condition ( Nmm ) (N) ( N/mm² ) ( N/mm² ) ( N/mm² ) ( N/mm² ) MID-POINT 19.14 7,867,429 0.0000007 159.98 183 165 0.97 OK. LOAD-POINT -38.29 7,867,429 -0.000001 159.98 183.33 165 0.97 OK.
10 .3
CASE 2:
INFLUENCE OF 10" (254mm) OF RAIN ACCUMULATED ON CENTER DECK
10" Rain
For deck to support 10" (254mm) of rain water: Volume of rain water collected at the deck, Vrain = Adeck x Hrain where Adeck = Hrain =
=
233.99
m³
π /4 x Øir 2 Area of deck = Rain accumulation of 10"
Vol. rain x ρ
rain
= 921,213,536.64 mm³ = 254 mm = 233,988.24 kg
Weight of 10" accumulated rain water, Wrain =
Upward Bouyant Load = Deck Area x Floatation Height x Product density = π /4 x (Øir) 2 x H (rain) x ρ Downward load due to deck steel and rain water, = W deck + W rain Nett downward force acting on deck = (Upward bouyant load - Downward Load) = Deck Area
=
242,429.27 kg
=
291,840.45 kg
75
=
53.64
kg/m2
qα Et
4 4
= K
1
y + K t
2
y t
3
( 11.11.1)
σα
Et
Where: t= α= q= y= σb = σd = σ= v= E=
2 2
= K
3
y + K t
4
y t
2
( 11.11.2)
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/mm2
0.3 200,000 N/mm²
The deck plate is fixed and held at its outer edge by the pontoon, hence condition is consider as: Case 3 Fixed and Held. Uniform pressure q over entire plate K1 = K2 = At the Centre, K3 = K4 At the edge, K3 = K4 For 4 1 - ν2 = =
4
5.33 1 - ν2 2.6 1 - ν2
K 3 = 2 1 − v
=
5.86
=
2.86
2 1- ν
= =
2.86 0.976
4.40 1.73 55,228.70
qα Et4 y t
=
And
K1
+ K2
y
y t
3
= =
q α4 Et4 214.38325 mm
=
55,140.73
Solving equation 11.11.2 σα² E. t 2 = K3 y t = = At Deck Center, + K4 777.4581306 1360.154003 y t 2
(at Deck Center) (at Deck Edge)
2 33.94 N/mm 2 3.34 N/mm 2 30.60 N/mm
σtotal σbending σdiaphgram
At Deck edge,
= = =
σtotal σbending σdiaphgram
= = =
2 59.37 N/mm 3 5.14 N/mm 4 54.23 N/mm
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
PONTOON STRESS DESIGN - CASE 2 PONTOON PROPERTIES Nominal diameter of Inner Rim, Øir Section modulus available, Za2 = Cross sectional area, Aa
= = =
34248 mm 27019626.01 mm3 49,176 mm²
10 .4.2
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 PONTOON RING DESIGN
: SA 516 Gr. 65N = 275.00 N/mm² = 1.000 = 1.00 = 183.33 N/mm² = 165.00 N/mm²
10 .4.3
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, Rh.Do Mm = 4 At Reaction-Point, Bending moment, Rh.Do Mr = 4 10 .4.4 RESULT RING STABILITY CHECK Bending Moment Circumferential force Bending Stress Circumferential stress Allow. bending stress Allow. axial stress Unity Check Condition ( Nmm ) (N) ( N/mm² ) ( N/mm² ) ( N/mm² ) ( N/mm² ) MID-POINT 18.08 7,429,209 0.0000007 151.07 183 165 0.92 OK. LOAD-POINT -36.15 7,429,209 -0.000001 151.07 183 165 0.92 OK. α 1 tan α 1 Tr = 2 tan α sin α 1 α 1 Tm = 2.sin α
Circ. tensile force, Rh
Circ. tensile force, Rh
10 .4.5
STRESSES SUMMARY LOAD CASE 1 Deck Center Deck Edge 35.92 62.84 3.52 32.40 5.41 57.43 LOAD CASE 2 Deck Center Deck Edge 33.94 59.37 3.34 30.60 5.14 54.23
σtotal ( N/mm² ) σbending ( N/mm² ) σdiaphgram ( N/mm² )
11 .0
ROOF SUPPORT LEG DESIGN 22 15 10 5 Nos. at R4 Nos. at R3 Nos. at R2 Nos. at R1 18541.00 13716.00 8839.00 4267.00
11 .1
GEOMETRIC DATA Support leg size Pipe outside diameter Pipe Thickness, Pipe Area, Aleg Radius of gyration, r = I Aleg Do2 - Di2 4 = 3" Sch. 80 = 88.9 = 7.62 = 1,945.76 = 24.89 mm mm mm2
11 .2
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 : Deck O.D Deck Thickness, td Deck Area, Adeck Center deck weight, Wdeck Design Live Load, Llive Effective radius for area of deck supported by leg: R3eff =
: SA 333 Gr 6 = 241 N/mm² 209,000 N/mm² = = 7,850 kg/m³
11 .3
Lsp1 Lsp2 Lsp3 Lsp4
= = = =
2927 2927 2927 2940
mm mm mm mm
= 34231 =8
mm mm 2 = 920,299,220.87 mm = 57,794.79 kg KN/m2
= 1.2
1/2(Øir/2-R3) = 15415.75 R2eff = 1/2(R3-R2) = 11277.5 R1eff= 1/2(R2-R1) = 6553
Area of deck supported by legs at i) ii) iii) iv) R1 = π(R1eff)2 R2 = π((R2eff) - (R1eff) ) R3 = π((R3eff) - (R2eff) ) R4 = p((Ødeck) - (R3eff) )
2 2 2 2 2 2 2 = 134,905,671.69 mm 2 = 264,648,384.82 mm 2 = 347,030,823.13 mm 2 = 173,714,341.24 mm
11 .4
SUPPORT LEG AT INNER DECK R1 No. of legs at R1 Area of deck supported by legs at R1, A1 Deck area on each leg, A1' Deck load on one leg = Live load on one leg = Total load on one leg = Wdeck x A1' Adeck
= = = = = = Total Load / Aleg =
5 26,981,134.34 mm2 1,694.42 kg 16.62 KN 32.38 KN 49.00 KN
2 25.18 N/mm
= 134,905,671.69 mm2
Llive x A1' Deck load + Live load
Stress on support leg at inner deck R1, P1 = 11 .4.1
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 < Sc.all, the support leg at inner deck R1 is satisfactory.
= =
118 1
=
130.84
=
75.08 N/mm²
=
77.80 N/mm²
= =
74.20 N/mm² 75.08 N/mm²
11 .5
SUPPORT LEG AT INNER DECK R2 No. of legs at R2 Area of deck supported by legs at R2, A2 Deck area on each leg, A2' Deck load on one leg = Live load on one leg = Total load on one leg = Wdeck x A2' Adeck
= = = = = = =
10 26,464,838.48 mm2 1,661.99 kg 16.30 KN 31.76 KN 48.06 KN
2 24.70 N/mm
= 264,648,384.82 mm2
Llive x A2' Deck load + Live load
Stresses on support leg at inner deck R2, P2 = 11 .5.1 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
= =
118 1
=
130.84
When λ ≤ Cc, [ 1 - λ² / 2Cc² ].Sy Sc.all = (i) = 75.08 N/mm² 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 <
(ii)
=
77.80 N/mm²
= = satisfactory.
74.20 N/mm² 75.08 N/mm²
Sc.all, the support leg at inner deck R2 is
SUPPORT LEG AT INNER DECK R3 No. of legs at R3 Area of deck supported by legs at R3, A3 Deck area on each leg, A3' Deck load on one leg = Live load on one leg = Total load on one leg = Wdeck x A3' Adeck
= = = = = = Total Load / Aleg =
15 23,135,388.21 mm2 1,452.90 kg 14.25 KN 27.76 KN 42.02 KN
2 21.59 N/mm
= 347,030,823.13 mm2
Llive x A3' Deck load + Live load
Stresses on support leg at inner deck R3, P3 = 11 .6.1
ALLOWABLE STRESS As per AISC code, Slenderness ratio, λ = K.Lsp3 / 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 P3 < Sc.all, the support leg at inner deck R3 is
= =
118 1
=
130.84
=
75.08 N/mm²
=
77.80 N/mm²
= = satisfactory.
74.20 N/mm² 75.08 N/mm²
11 .7
SUPPORT LEG AT PONTOON No. of legs at R4 Area of deck supported by legs at R4, A4 Deck area on each leg, A4' Deck load on one leg = Wdeck x A4' Adeck
= = = = = = = = = =
27 6,433,864.49 mm2 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
= 173,714,341.24 mm2
Pontoon weight, Wpontoon Pontoon weight on one leg, Wpontoon' Live load on one leg = Total load on one leg = Llive x A4' Deck load + Live load + Pontoon weight Total Load / Aleg
Stresses on support leg at Pontoon, P4 = 11 .7.1
ALLOWABLE STRESS As per AISC code, Slenderness ratio, λ = K.Lsp4 / 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 P3 < Sc.all, the support leg at inner deck R3 is
= =
118 1
=
130.84
=
74.62 N/mm²
=
77.12 N/mm²
= = satisfactory.
73.93 N/mm² 74.62 N/mm²
11 .8
STRESSES SUMMARY Actual stress, (N/mm2) 25.18 24.70 21.59 31.33 Allowable stress, (N/mm2) 75.08 75.08 75.08 74.62
Leg at radius 4267.00 8839.00 13716.00 18541.00
No. of leg 5.00 10.00 15.00 22.00
RESULT OK OK OK OK
12 .0 12 .1
BLEEDER VENT CALCULATION 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 OPERATING VENTING NORMAL VACUUM VENTING Maximum liquid movement out of a tank Flow rate of free air, Vv1 ( = Vo/15.9 x 15.89 )
FP
)
: API STD 2000 = 39000 = 20700 24000 = 2.50 = 67 = 427 = 1,100
mm mm m³ mbarg °C m³/hr m³/hr
12 .2 12 .2.1
=
1097.23 m³/hr
12 .2.2
Thermal inbreathing Tank capacity, V From Table 2, column 2 (Thermal Venting Capacity Req't ), Flow rate of free air,Vv2 (@ 0 ft³/hr ) Total vacuum flow required, Vv ( = Vv1 + Vv2 )
= = =
155,535 barrels 0 m³/hr 1,097 m³/hr
12 .3 12 .3.1
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 ) 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 ) OPEN VENT SIZING ( BLEEDER VENT SIZING ) OPEN VENT SIZING CALCULATION Maximum flow, Q ( @ Vacuum flow at ( @ Q= where K= A= g= H= K. A. 2. g. H Discharge coefficient cross sectional area of vent acceleration due to gravity Head as measure pressure differential Dp H= g
= =
0.17 m³/hr 457 m³/hr
12 .3.2
= =
0 m³/hr 457 m³/hr
12 .4
2.50
mbarg. )
=
1,097 m³/hr
0.62
=
21 m
Minimum require cross sectional area of vent, Av_req = where Q= g= r= Dp = 12 .5 Q K. 2. g. H = Q K g 2. g. Dp = = = =rg = = = 0.0241 m² 24,124 mm² 0.3048 mm³/s 11.812 kg/m2s2 1.204 kg/m³ 250 N/m²
Max. Air flow required Specific weight of Air Air density Differential pressure
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, Av_actual Since Av_actual > Ar_gnv, therefore the nos. & size of vents is
: =
8" Sch Std 1 219 = 202.64 mm = 32,251 mm² satisfactory.
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 Roof Deck Area Design Rain Fall Design drainage required, Qreq. No. of Roof Drain, N Roof drain pipe size (rigid & fitting) Dain Pipe Outside Diameter, Do Drain pipe thickness Drain Pipe length : L1 = Rigid L2 = Flexible 13 .2 = = = = = = = = = = = 39,000 20,100 1500 225 mm mm mm mm
920.30 m2 50 mm/hr 46.01 m3/ hr 2 4" Sch 80 101.6 mm 8.56 mm
20 m x 23.14 m x
2 1
nos. nos.
= =
40 m 23.14 m
Number of Fitting & Accessories per drain pipe - 45º elbow 90º elbow Valve Rigid pipe Flexible pipe
N45º N90º Nv
= = = = =
2 1 1 2 1
13 .3
TOTAL HEAD H = h+ V2 2g
13 .4
TOTAL HEAD LOSS OF ROOF DRAIN PIPE V2 x 2g K L' D
h= Where H = G = K =
L' = D = 13 .5
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
m
K1 K2
= 0.0168 = 0.03 = 0.08448 m
EQUIVALENT PIPE LENGTH OF VALVE AND FITTING Accordance to NFPA 15 Table 8.5.2.1, 45º elbow, L45º Equivalent length for 4" 90º elbow, L90º Valve, Lv Total equivalent pipe length for RIGID PIPE: L1' = L1 + N45º x L45º + N90º x L90º + Nv x Lv Total equivalent pipe length for Flexible PIPE: L2' = L2
= = =
3.1 1.2 0.6
=
48 m
=
23.14 m
13 .6
TOTAL HEAD LOSS OF ROOF DRAIN PIPE h= H= H= V2 2g K1 L1' D + K2 L2' + 1 D V2 x 2g K1 L1' D + K2 L2' D
13 .7
FLOW VELOCITY 2gH V= K1 L1' D + K2 L2' + 1 D = 1.15 m/s
13 .8
DRAINAGE FLOW RATE PER DRAIN PIPE Q = AREA x Velocity = π/4 x D2 x V x 3600 (s/hr) = 23.30 m3 / hr
13 .9
MINIMUM ROOF DRAIN REQUIRED Drainage flow rate required Nreq = Actual flow rate per drain MINIMUM REQUIRED
= = 2
1.97
14
WEIGHT ANALYSIS ITEM NO : 7061T-3901
1 GENERAL Design code : API 650 11th Edition Inside diameter : 39,000 mm Steel density Shell / Btm : 7,850 kg/m³ Roof : 8,027 kg/m³ 2 SHELL COURSES ONE - FOOT METHOD (OUTER TANK) Course No. Material 1 2 3 4 5 6 7 8 9 10 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 -
Type of roof support : NA Tank height : 20,700 Roof plates lapping factor : 20.70
Type of roof : Floating Roof mm Annular/Bottom plates lapping factor : 1
Y Thickness (mm) 28.00 25.00 22.00 19.00 16.00 13.00 11.00 11.00 11.00 Width (mm) 2,440 2,440 2,440 2,440 2,440 2,440 2,020 2,020 2,020 Weight (kg) 65,757 58,707 51,658 44,611 37,564 30,518 21,377 21,377 21,377 352,948 kg
Total weight of shell plates = 3 BOTTOM PLATES Material A 516 GR. 65N 4 TOP CURB ANGLE Material A 516 GR. 65N 5 TOP WIND GIRDERS Material A 516 GR. 65N Y Thickness (mm) 9.00 Outside Dia. (mm) 39,130 Y Size 76 x 76 x 6.4 Qty 1 Length (mm) 122,827 Unit Weight (kg/m) 10.33 Y Size Qty 1 Length (mm) 125,183 Unit Weight (kg/m) 87.51 Y Qty 1 Length (mm) 124,476 Unit Weight (kg/m) 53.76 Y 1,500 Y 5.00 % of total weight Y 16,820 = 22,916 = = Weight (kg) 6,691 Weight (kg) 10,955 Weight (kg) 1,269 Weight (kg) 84,961
=
84,961 kg
=
1,269 kg
T 825 x 250 x 8 x 10
=
10,955 kg
6 INTERMEDIATE WIND GIRDERS Material Size A 516 GR. 65N 7 NOZZLES Total weight of nozzles 8 MISCELLANEOUS Assuming T 405 x 150
=
6,691 kg
1,500 kg
22,916 kg
9 STAIRWAY & PERIMETER PLATFORM Platform Weight 165.00 KN 10 OPERATING LIQUID WEIGHT Operating liquid height 11 HYDROSTATIC WATER WEIGHT Hydrostatic water height ERECTION WEIGHT (Exclude roof) OPERATING WEIGHT FIELD HYDROSTATIC TEST WEIGHT
16,820 kg
(@ =
20,700
mm & sg @=
1.00 )
=
24,728,026 kg
(@
20,700
mm )
= = = =
24,728,026 kg 498,060 kg 25,226,086 kg 25,226,086 kg
