Calculation API 650

ROOF THICKNESS VERIFICATION AS PER API 620

Contents:

1 Design Data

2 Roof Design

3 Shell Desin

4 Compression Area Design

5 Bottom Plate Design

6 Intermediate Wind Girder Calculations

7 Stabiltility Calculations Against Wind Load

8 Stabiltility Calculations Against Seismic Load

8.1 Resistance To Over Turning

8.2 Shell Compression For Unanchored Tanks

8.3 Maximum Allowable Shell Compression For Unanchored Tanks

8.4 Shell Compression For Anchored Tanks

8.5 Maximum Allowable Shell Compression For Anchored Tanks

9 Uplift Load Cases As Per API 650 Table 3-21a

10 Anchor Chair Calculations

11 Foundation Loading Data

12 Nozzle Reinforcement Calculations(LATER)

13 Nozzle Flexibility Analysis As Per Appendix P of API 650(LATER)

14 Venting Calculations As Per API 2000(LATER)

7.1) Roof Thickness and Compression Area Verification As Per API 620

Nomenclature

P =particular condition of loading.

=

P1 =consideration in the tank.

Pg =

of the tank. Pg is the positive except in computation used to investigatethe ability of the tank to withstand a partial vacuum; in such computations its value is negative.

= Meridional unit force in lbs/inch of latitudinal arc, in the wall of the tankat the level of the tank under consideration.

= Latitudinal unit force in lbs/in of maridional arc, in the wall of the tankunder consideration. T2 is positive when in tension.(in cylinderical side walls the latitudinal unit forces are circumfrential unit forces)

= Radius of curvature of the tank side wall in inch in a meridional plane

as provided in 5.10.2.6

= Length in inch of the normal to the tank wall at the level under consideration measured from the wall of the tank to the axis of the

W = Total weight in lbs of that portion of the tank and its contents(eitherabove the level under consideration, as in figure 5-4 panel b, orbelow it, as in figure 5-4 panel a) that is treated as a free body on the computations for that level. Strictly speaking the total weight would include the weight of all metal, gas and liquid in the portion of thetank treated as described; however the gas weight is negligible andthe metal weight may be negligible compared with the liquid weight.W shall be given the same sign as P when it acts in the same

Total pressure in lbs/ft2 acting at a given level of the tank under the

P1 + Pg

Pressure in lbs/ft2 resulting from the liquid head at the level under

Gas pressure in lbs/ft2 above the surface of the liquid. Thwe maximumgas pressure(not exceeding 15 lbs/ft2) is the nominal pressure rating

T1

T1 is positive when in tension.

T2

R1

at the level under consideration. R1 is to be considered negativewhen it is on the side of the tank wall opposite from R2 except

R2

revolution. R2 is always positive except as provided in 5.10.2.6

direction as the pressure on the horizontal face of the free body;it shall be given the opposite sign when it acts in the opposite direction.

=at the level under consideration.

t = Thickness in inch of the side walls, roof or bottom of the tankat the level under consideration.

c = Corrosion allowance in inch

E = Joint efficiency

=table 5-1

=in 5.5.4

Design Data :

Desig CodeClient's Specs

Fluid Sulphuric AcidMaterial A36Design Density of Contents = 1820

= 113.623Density of water for hydrotest 1000

= 62.43Specific Gravity Of Contents 1.82Material Yield Strength = 248.21

= 36000Design Temperature 100Internal Pressure = 1.015

146.16Extrenal Pressure = 0.0725Liquid Level = 4200

= 13.78Design Liquid Level = 4200

= 14Allowable Tensile Stress At Design Temperature = 110.32

16000Corrosion Allowance

Shell 6.4

At Cross section area in in2 of the side walls, roof or bottom of the tank

Sts Maximum allowable stress for simple tension in lbs/in2 as given in

Sca Allowable compresive stress in lbs/in2 established as prescribed

API 620 10TH Ed. ADD.01

0.25197Bottom 6.4

0.25197Roof 6.4

0.25197

Inside Dia Of Tank D = 400013.12

Nominal Dia Of Tank = 401013.16

Outside Dia of tank = 402013.19

158.27Height Of Shell = 4200

14Weight Of Compression Ring IF applicable 450Weight Of Accessories = 3000Wind Velocity = 96.31

Yield Strength Of Steel Structure = 36000Roof Angle = 11.3

Roof Design As Per API 620 B 5.10.2

Assumptions

Taking Thickness t = 14 mm= 0.551 inch

Joint Efficiency E = 0.7

Radius Of Dome = 1 x D= 13.12 ft

Height Of Cone Roof h = 1.31 ft

One Half The included apex angle a = 78.7of the Conical roof or bottom .Radius Of Cone L = 6.69 ftAngle b/w the normal to roof q = 11.30and a vertical line at the roof to shell juncture

Roof Area = 20256= 141

Roof Weight = Density x t x Roof Area3163

Dn

D0

rr

At'

W (Uncorroded)

Roof Weight = 1719

Cross sectional Area = 19478at roof to shell junction = 135

As per API 620 5.10.2.5.a

For Conical Seg. = Infinity ft

As per API 620 5.10.2.5.a

= 6.562 ft= 78.74 inch

Case I : Thickness At The Top Head Edge Against Internal Pressure

= -0.162 psi= -0.156 psi

(force acting in downward direction)Now Calculating Meridional and Latitudinal Forces

= Equation 8 of 5.10.2.5

= 171 lbf/in

= Equation 9 of 5.10.2.5

408 lbf/inNow As Per 5.10.3.2

T =408 lbf/in

== 0.288 inch

Provided Thickness is Ok

Case II : Thickness At The Top Head Center Against Internal Pressure

=

= 0 lbf/in

== 0 lbf/in

W (corroded)

At

R1

R3 = D/2

W/At

W/At'

T1 {R3/(2Cosa)}*{P+W/At}

T2 {(P × R3)/(Cosa)}

If T1 and T2 both are +ve, then

Max.(T1 and T2)

tcalc. T/(Sts.E) + C.A

T1' Rs/2(P+W/At')

T2' Rs x (P+W/At') - T1

Now As Per 5.10.3.2

T == 0 lbf/in

=0.252 inch

As these thicknesses are calculated based on the internal pressure of = 1.015 psi

Therefore,Back calculating the internal pressure limited by the actual provided thickness

=

T == 3351 lbf/in

maximum calculated thickness

=

T =

P == #DIV/0!

#DIV/0!

As Per 7.18.3.2, our roof will be safe against the hydro test pressure of 1.25 x internal pressure i.e. 1.26875 psi

Case II : Thickness At The Top Head Edge Against External Pressure

W = - (Live Load + Dead Load) x Roof Area -ve sign id due to the downward direction of load

=

= -4985 lbf

= -0.256 psi

If T1 and T2 both are +ve, then

Max.(T1' and T2')


tprov. T/(Sts.E) + C.A

(tprov. - C.A) X Sts X E

Now putting this value of T in the equation of T2, where we find the

T2 Rs x (P+W/At x cos a) - T1

Rs x (P+W/At x cos a) - Rs/2(P+W/At)T2 = T

(2 X T/Rs) - W/At(2*cos a -1)

-(25 + weight of roof in lbs/ft2) x roof area

W/At

= -0.246 psi

Now Calculating Meridional and Latitudinal Forces

= Equation 8 of 5.10.2.5= -66.0 lbf/in

= Equation 9 of 5.10.2.5-29.1 lbf/in

Now As Per 5.10.3.5

T' == 66.0 lbf/in

T" =29.1 lbf/in

Similarly,R' = Infinity

R" = 78.74 inchNow,

= Sqrt{(T'+0.8 X T") X R'}/1342 Solving By Equation 18 of API 620

= Infinity inch

= SQRT{T'' x R''}/1000 + CA Solving By Equation 19 of API 620

0.300 inch

Now; As per 5.10.3.5.b Step-2

= Infinity < .0067R'

= 0.0006 < .0067R''

== 0.300 inch= 0.551 inch

As per 5.5.4.3

Provided thickness is O.K

Case IV : Thickness At The Top Head Center Against External Pressure

W/At'

T1 {R3/(2Cosa)}*{P+W/At}

T2 {(P × R3)/(Cosa)}

Max.{ABS(T1) , ABS(T2)}

Min.{ABS(T1) , ABS(T2)}

t18

t19

t18 - C.A

t19 - C.A

treq Max(t18 , t19)treq

tprovided

Allowable Compressive Stress; Sca

=

= 0.00 lbf/in

== 0.00 lbf/in

Now As Per 5.10.3.5

T' =0.00 lbf/in

T" =0.00 lbf/in

Similarly0.00 inch0.00 inch

Now,= Sqrt{(T'-0.8 X T") X R'}/1342 +Solving By Equation 18 of API 620

0.252= SQRT{T'' x R''}/1000 + CA Solving By Equation 19 of API 620

0.252Now; As per 5.10.3.5.b Step-2

= #DIV/0! < .0067R'

= #DIV/0! < .0067R''

=

= 0.252 inch= 0.551 inch

As per 5.5.4.3(t - C.A)

R'= #DIV/0!

As these thicknesses are calculated based on the external pressure of P = 0.0725 psi

Therefore,Back calculating the external pressure limited by the actual provided thickness

Now; As per 5.10.3.5.a

= SQRT{T'' x R''}/1000 + CA

T1' Rs/2(P+W/At' )

T2' Rs(P+W/At' ) -T1'

Max.{ABS(T1' ) , ABS(T2' )}

Min.{ABS(T1' ) , ABS(T2' )}

R' = R2

R" = R1

t18

t19

t18 - C.A

t19 - C.A

treq Max(t18 , t19)

treq

tprovided

Allowable Compressive Stress; Sca = 106 x

Sca

t19

= SQRT{T'' x R''}/1000 + CA

T'' =

T'' = #DIV/0! lbs/in

T'' =

=#DIV/0! Psi

NOTE:

meter square area.for this purpose, by considering the roof segment of 700mm diamter which is equivelant to 0.4 meter squre area is to be analysed against these loading #DIV/0!

For result and methodolgy see ANNEXURE 1

3) Shell Design

Shell calculations are based on different assumed thicknesses, here we will perform

the specimen calculations for 1st shell course and the others are given in the tabulated

form which are mentioned below.

Case I : Thickness of 1st shell course Against Internal Pressure

Joint Efficiency E = 0.85

Taking thickness of Ist Shell Course = 0.630 inchTotal weight of shell of different = 26004 lbsthicknesses.

Total weight of roof = 3163 lbsTotal Weight; W (Roof Pl.+Shell)= 29167 lbs

= 1.50 psiNow Total Pressure

Internal Pressure + Pressure due to liquid head

= 24.31 psi

Now calculating the latitudinal and maridianal forces

As Per 5.10.2.5.c

= equation 10 of 5.10.2.5= 1,016 lbs/inch

= Rc x P equation 11 of 5.10.2.5= 1,915 lbs/inch

Now As Per 5.10.3.2

T =

tprovided

[(tprovided-C.A) x 1000 ]2 / R''

-Rs/2(P+W/At' )

Pext 2/Rs x T'' - W/At'

As Per 32-SAMSS-006 Para 5.4.k, roof live loads shall not be less than concentrated load of 225 Kgs over 0.4

W/At

T1 Rc/2(P+W/At)

T2

If T1 and T2 both are +ve, thenMax.(T1 and T2)

= 1,915 lbs/inch

== 0.39 inch

The same procedure is adopted while confirming the thickness during hydrotest

As this thickness is calculated based on the internal pressure of P = Internal Pressure + Pressure due to liquid head

= 24.31 psiBack calculating the internal pressure limited by the actual provided thickness

=

T = 5,140 lbs/inch

maximum calculated thickness

= Rc x P

== 65.28 psi

Case II : Thickness of 1st shell course Against External Pressure

W = -(Weight Of Roof Plates + Weight Of shell + Live Load)= -32684 lbs= -0.0725 psi

-ve sign id due to the downward direction of loadNow calculating the latitudinal and maridianal forces

As Per 5.10.2.5.c

= equation 10 of 5.10.2.5-69 lbs/inch

= Rc x P equation 11 of 5.10.2.5-5.71 lbs/inch

Now As Per 5.10.3.5

T' = 69 lbs/inch

T" = 6 lbs/inch

similarly,


tprov. T/(Sts.E) + C.A

Now putting this value of T in the equation of T2, where we find the

T2

Pmax.int T2/Rc T2=T

Pext.

T1 Rc/2(P+W/At)

T2

Max.{ABS(T1) , ABS(T2)}

Min.{ABS(T1) , ABS(T2)}

R' = Rc = 78.74 inchR" = Rc = 78.74 inchNow,

= Sqrt{(T'+0.8 X T") X R'}/1342 + C.A Solving By Equation 18 of API 620= 0.3087 inch= SQRT{T'' x R''}/1000 + CA Solving By Equation 19 of API 620= 0.2732 inch

Now; As per 5.10.3.5.b Step-2

= 0.0007 < .0067R'

= 0.0003 < .0067R''

== 0.3087 inch

As per 5.5.4.3(t - C.A) R'

= 0 Psi

Back calculating the external pressure limited by the actual provided thickness

Now; As per 5.10.3.5.aas the maximum thickness is obtained by equation 18, therefore back

= Sqrt{(T'+0.8 X T") X R'}/1342 + C.A

= T'-0.8 X T"

=

Now Putting the values in the above equation

= -31.27 Psi

-ve sign shows the vacuum condition.

Assuming Thicknesses of Various Shell Courses and Calculate their Weights

Now following the above mentioned procedure for the calculation of remaining shell courses.

CASE 1. Internal Pressure With Full of Liquid

Table 1.

t18

t19

t18 - C.A

t19 - C.A

treq Max(t18 , t19)

Allowable Compressive Stress; Sca = 106 x

Sca

calculating the external pressure limited by tprov.

t18

{1342 x (tprov.-C.A)}2/R'

{1342 x (tprov.-C.A)}2/R' -Rc/2(P+W/At)- 0.8 x (Rc x P)

Pmax.ext.

Shell Thickness Width Weights

Coures # mm inch mm inch Kgs

1 16 0.630 2450 96.46 3,863 2 14 0.551 2450 96.46 3,380 3 12 0.472 2450 96.46 2,897 4 10 0.394 1650 64.96 1,626 5 0 0.000 0 0.00 - 6 0 0.000 0 0.00 -

Total Weight Of Shell =

Table 2.

lbs lbs lbs lbs Psi

1 3,163 26,004 29,167 29,167 1.50 2 3,163 17,467 20,630 20,630 1.06 3 3,163 9,997 13,160 13,160 0.68 4 3,163 3,594 6,756 6,756 0.35 5 3,163 - 3,163 3,163 0.16 6 3,163 - 3,163 3,163 0.16

Table 3.

Psi Psi Psi Psi Psi

1 1.015 23.30 12.80 24.31 14.072 1.015 16.96 9.32 17.97 10.593 1.015 10.61 5.83 11.63 7.104 1.015 4.27 2.35 5.29 3.625 1.015 0.00 0.00 1.02 1.276 1.015 0.00 0.00 1.02 1.27

Now Calculating Meridianal and Latitudinal Forces aginst pressure and

During Hydrotest Condition.

Psi Psi lbs/inch lbs/inch

1 25.81 15.57 1,016.22 612.92

Shell Coures #

Weight of Roof

Weight of Shell

Total Weight W

Total Weight WHydrotest

W/At

Shell Coures #

Internal Pressure

Contents Pressure

head

Water Pressure

Head

Total Pressure

PContents

Total Pressure

PHydrotest

As Per 7.18.3.2 Internal Presssure for Hydrotest is 1.25 * Pint

Shell Coures #

Pcon.+W/At internal

Phydro+W/At Hydrotest

T1 T1hydro

2 19.03 11.64 749.25 458.46 3 12.30 7.78 484.44 306.16 4 5.63 3.96 221.79 156.01

5 1.18 1.43 46.35 56.34 6 1.18 1.43 46.35 56.34

lbs/inch lbs/inch lbs/inch lbs/inch

1 1,914.53 1,107.93 1,914.53 1,107.93 2 1,415.11 833.52 1,415.11 833.52 3 915.69 559.11 915.69 559.11 4 416.27 284.71 416.27 284.71 5 79.92 99.90 79.92 99.90 6 79.92 99.90 79.92 99.90

Now Calculating the required thickness as Per 5.10.3.2

inch inch inch inch

1 0.39 0.33 OK OK

2 0.36 0.31 OK OK

3 0.32 0.29 OK OK

4 0.28 0.27 OK OK

5 0.26 0.26 Not OK Not OK

6 0.26 0.26 Not OK Not OK

Now Back Calculating the pressure limited by actual provided thicknesses.

T

lbs/inch Psi inch

1 5,140 65.28 OK

2 4,069 51.68 OK

3 2,998 38.08 OK

4 1,928 24.48 OK

5 (2,822) (35.84) Not OK

6 (2,822) (35.84) Not OK

CASE 2. External Pressure In Empty Condition

Shell Coures #

T2 T2hydroT{Max.(T1,T2)}

T{Max.(T1hyd.,T2hyd.)}

Shell Coures #

tcalc. thydro tcalc<tprov. thydro<tprov.

Shell Coures #

Pmax. internal Pmax.inter>Pint.

Live Load

Psi lbs lbs lbs lbs

1 -0.0725 3,163 26,004 3516.60 -32683.742 -0.0725 3,163 17,467 3516.60 -24146.343 -0.0725 3,163 9,997 3516.60 -16676.114 -0.0725 3,163 3,594 3516.60 -10273.065 -0.0725 3,163 - 3516.60 -6679.516 -0.0725 3,163 - 3516.60 -6679.51

Psi Psi lbs/inch lbs/inch

1 -1.678 -1.750 -69 -5.7092 -1.240 -1.312 -52 -5.7093 -0.856 -0.929 -37 -5.7094 -0.527 -0.600 -24 -5.7095 -0.343 -0.415 -16 -5.7086614176 -0.343 -0.415 -16 -5.708661417

T' T'' R' R''

lbs/inch lbs/inch inch inch

1 69 6 79 79 2 52 6 79 79 3 37 6 79 79 4 24 6 79 79 5 16 6 79 79 6 16 6 79 79

inch inch inch inch

1 0.3087 0.2732 0.0007 0.0003 2 0.3016 0.2732 0.0006 0.0003 3 0.2944 0.2732 0.0005 0.0003 4 0.2871 0.2732 0.0004 0.0003 5 0.2822 0.2732 0.0004 0.0003 6 0.2822 0.2732 0.0004 0.0003

Shell Coures #

External Pressure

Weight of Roof

Weight of Shell

Total Weight W

Shell Coures #

W/At P+W/At T1 T2

Shell Coures #

Shell Coures #

t18 t19t18-C.A/

R'<.0067t19-C.A/

R'<.0067

Shell Coures #

tcalc. tcalc<tprov.

inch inch

1 0.3087 OK

2 0.3016 OK

3 0.2944 OK

4 0.2871 OK

5 0.2822 Not OK (3,200)6 0.2822 Not OK (3,200)

Now Back Calculating the pressure limited by actual provided thicknesses.

Psi inch

1 -31.27 OK

2 -19.53 OK

3 -10.53 OK

4 -4.29 OK

5 -14.05 OK

6 -14.05 OK

Compression Area Design As Per API 620

As Per 5.12.4.2

= Width in inch of roof consider to participate in resisting the circumfrential forces acting on the compression ring region.

Wc = Corresponding Width in inch of shell to be participating.

= Thickness in inch of roof at and near the juncture of theroof including corrosion allowance.

= Corresponding thickness in inch of shell at and near the juncture of the roof and shell.

= Length in inch of the normal to the roof at the juncture b/wthe roof and the shell measured from the roof to the tank vertical axis of of revolution.

Rc = Horizontal radius in inch of the cylinderical shell at its juncture with the roof of the tank.

= Circumfrential unit force in the shell side wall of the tankat its juncture with the roof in lbf/in measured along an

Shell Coures #

Shell Coures #

Pmax. External

Pmax.ext.>Pext.

Wh

th

tc

R2

T2s

element of the cylinder.

a =

Q = Total circumfrential force in lbs acting in a vertical crosssection through the corresponding ring region.

= Net Area in Inch2 of the vertical cross section of metal required in the compression ring region exclusive of of all corrosion allowances.

Now,

Calculating the Wh and Wc based on the acual provided thickess of the roof and shell.

== 2.91 inch

Wc == 2.91 inch

Now,As per 5.12.4.3

Q = equation 26

Therefore,

T2s =79.92125984 lbs/inch

Q = -11807

So, As per 5.12.4.3

= Q/15000 equation 27= 0.79 507.84

= 2.01 1295Provided thickness and the compression area is sufficient compared with values, achieved, based on API 620.

Angle b/w the direction of T1 and a vertical line .

AC

Wh 0.6 x {R2 x (th-C.A)}0.5

0.6 x {Rc x (tc-C.A)}0.5

T2 X Wh + T2s x Wc - T1 X Rc x Sin a

P X R3

AC

inch2 mm2

Aprovided inch2 mm2

Providing the compression Area As per Figure 5-6 of API 620 Detail f

Provided Thickened Plate t 36 mm1.417 inch

== 0.00 inch

Wc == 5.75 inch

Therefore,

=

= 6.7

As Aprov.>Areq. Compresssion Ring Is OK

As the required area for compression ring region is extra ordinary high

Therfore we will provide the Curved Knuckle region in order to avoid the

requirement of compression ring region.

Tori Spherical Head Knuckle Calculation (Per ASME Section VIII Division 1 Sec.4)

L = Inside Dish Radius 0 inch

P = Internal Design Pressure 1.015 psi

E = Joint Efficiency 0.7

t = Provided Thickness 0.551 inch

Wh 0.6 x {R2 x (t-C.A)}0.5

0.6 x {Rc x (t-C.A)}0.5

Aprov. Wh x (t-C.A) + Wc x (t-C.A)

inch2

r = Knuckle Radius(12% of diamet 100.8 inchof shell as per 5.12.3.1)

s = Material Allowable Design St 16000 psi

M =

= 0.75

= [{P X L X M}/{2 X S x E - 0.2 X P}] + C.A= 0.252 inch

Now back calculting the internal pressure limited by actual provided thickness.

== 112000.00 psi

5) Bottom Plate Design

Bottom Plate Area == 7140

Annular Plate Area == 13540

Joint Efficiency E = 0.7As per 5.9.4.2

= .25 + C.A= 0.502 inch= 10 mm

0.394 mm= .25 + C.A

0.502 inch10 mm

0.3937 inchTotal Weight =

= 2307 lbs= 830 lbs (Corroded)

Vacuum Calculations as Per ASME Section VIII Div.1

Weight of bottom plate resisting =external vacuum = 0.0402 psi

Effective External =Pressure = -0.0323 psi

0.25 X {3 + (L/r)0.5}

tcalc

Pmax. Int {2 x S x E x (tprov.-C.A)}/{L x M + 0.2 x (tprov.-C.A)}

p/4(Bottom OD-2 X Annular Ring Width)2

inch2

p/4(Bottom OD)2 - Bottom Plate Areainch2

tmin bottom

tprov bottom

tmin annular

tprov.annular

Density x (tprov.x Bottom Area + tprov x Annular Area)

0.2833 x tprov.bottom.corr.

Pbottom

Pext.eff Pext + Pbottom

As the weigt of bottom plate is greater than the vacuum.

So there is no need to calculate the thickness agianst vacuum.

for 1st shell course == 0.14 inch

for 1st shell course =0.38 inch

C == 0.12

Therefore,Thickness required against vacuum

== 0.318 inch

== 0.502 inch= 0.394 inch

Now back calculating the maximum external pressure limited by bottom plate

== -0.1132 psi

6) Design Of Intermediate Wind Girder As Per 5.10.6

=Where,

= Vertical Distance b/w the intermediate wind girder and the topof the shell or in the case of the formad head the vertical distance b/w the intermediate wind girder and the head bend line plusone third the depth of the formed head.

t = The thickness of the top shell course as ordered condition unless otherwise specified in inch.

D = Nominal tank diameter in ft.

= 1928.97 ft

Now, As per 5.10.6.1.a

Dynamic Pressure Against the wind velocity @ 100mph = 31

Dynamic Pressure due to internal vacuum = 5

Total Dynamic Pressure @ 100mph = 36

td ext (tcalc. - C.A)

tprov ext (tprov. - C.A)

0.33 X td ext./tprov

tvacuum OD X ( C X Pext.eff/S X E)0.5 + C.A

tcalc. Max.(tcalc.,tvac.)

tprov.

Pmax.ext. -[{tprov. - C.A}/OD}2 X {S X E/C} + Pbottom]

H1 6 x (100 x t) x (100xt/D)3/2

H1

H1

Now, As per 5.10.6.1.d

Dynamic Pressure due to vacuum = 10.44

Actual Dynamic Pressure = 41.44

Therefore H1 shell be decreased by the factor = 0.87

Now,= 1675.7 ft (after multiplying with load factor)

Transformed Shell Thicknesses As Per 5.10.6.2

Wtr =Where,

= Thickness Of Top Shell Course as ordered condition in inch.

= Thickness Of Shell Course for which transposed width is being calculated as ordered condition in inch.

W = Actual course width in ft

Wtr = Transposed course width in ft

1st Shell Course

Thickness Of First Shell Course = 0.630

Transposed Course Width Wtr = 3.92

2nd Shell Course

Thickness Of 2nd Shell Course = 0.551


3rd Shell Course

Thickness Of 3rd Shell Course = 0.472


4th Shell Course

Thickness Of 4th Shell Course = 0.394

H1

W X (tuniform/ttop)2.5

tuniform

ttop

t1

t2

t3

t4


5th Shell Course


Transposed Course Width Wtr = #DIV/0!

6th Shell Course


Transposed Course Width Wtr = #DIV/0!

Now,Transformrd height of shell = 22.83

As Htr<H1Intermediate Wind Girder In Not Required

7) Stability Calculations Against Wind Load Per ASCE-02

Wind Velocity V = 0.0

Height Of Tank including Roof Height = 15.1= 4.6

Effective Wind Gust Factor = 0.85

Force Coefficient = 0.7

Wind Directionality Factor = 0.95

Velocity Pressure Exposure Co-eff = 0.95

Topo Graphic Factor = 1

Importance Factor I = 1.25

V = 38.89

Design Wind Pressure =

= 1.046

Design Wind Load =

t5

t6

Htr

Ht

qf

Cf

Kd

Kz

Kzt

qz 0.6013 x Kz x Kzt x Kd x V2 X I/1000

P1 qz x D0 x qf x Cf x Ht

= 11.51

Overturning Wind Moment

=2

= 26

19530

Resisting Moment

3 2

Ws' = Total Weight Of Tank Shell 13426 lbs

Wr' = Total Weight Of Tank Roof 1719 lbs

8555 lbs-ftUplift is graeter than shell and roof weight

As Mw>Mr Anchorage is Required

8) Stability Calculations Against Seismic Load Per API 620 Appendix. L

= Over Turning Moment Due To Siesmic Forces=

Therefore,Z = Seismic Zone Factor From Table L-2

= 0.075 For Seismic Zone OneI = Importance Factor

= 1.25S = Site Amplification Factor From Table L-3

= 1.2= Lateral Earthquake Force Coefficient= 0.6 As Per L.3.3.1

C2 = Lateral Earthquake Force Coefficient= 0.75 X S As Per L.3.3.2

Where TT = Natural Period Of First Slosh As Per L.3.3.2

=And

k = Factor For D/H Obtained From Figure L-4So,

Mw P1 X Ht

Mr 2 x (Ws' + Wr' - Uplift Due to Internal Pressure)

Mr

Ms

Ms Z x I x {C1 x WS x XS + C1 x Wr x Ht + C1 x W1 x X1 + C2 x W2 x X2}

C1

k x OD0.5

D/H = 0.957Now,

k = 0.607 From Figure L-4

T = 2.204

C2 = 0.4083

Now,From Figures L-2 and L-3

= 0.375 From Figure L-3= 0.585 From Figure L-3= 0.543 From Figure L-2= 0.461 From Figure L-2

Where= Weight of tank Contents @ Maximum Liquid Level= 211,777 lbs

So,= 5.17= 8.06= 114,994.96 = 97,629.24 = Height From The Bottom Of Tank Shell To The Shell Centre Of Gravity = 6.89 ft

Now,

= 107498= 26,150 = 356,530 = 321,305.66

= 76,077 lbs-ft

8.1) Resistance To Over Turning Per API 620 Appendix. L.4

Assuming No Anchors are provided

=

= 2837.1 lbs/ftNow,

1.25 x G x H x D = 413.5 lbs/ft

AS WL>1.25GHD Therefore WL=1.25GHD

= 413.5 lbs/ft

8.2) Shell Compression For Unanchored Tanks Per API 620 Appendix. L.5.1

X1/HX2/HW1/Wt

W2/Wt

Wt

X1

X2

W1

W2

Xs

C1 x WS x XS

C1 x Wr x Ht

C1 x W1 x X1

C2 x W2 x X2

Ms

WL 7.9 x tb x (Fby x G x H)0.5

WL

Ms = 0.39

Where,== 704 lbs/ft

As Ms/{D2*(Wt+WL)<0.785 Use b=Wt+ 1.273*Ms/D2

The Maximum Longitudinal Compressive Force at The Bottom Of The ShellSo,

b =

= 1,260.68 lbs/ft

8.3) Maximum Allowable Shell Compression For Unanchored Per API 620 Appendix. L.5.3

b/12t = Maximum Longitudinal Compressive Stress= 166.78 psi

Now,

< 1.00E+06

So,

= 10994

As GHD2/t2<1000000 Use Fa=(1000000*t/2.5*D)+600*sqrt(GH)

Therefore,

= 1000000 x t

2.5 x D= 22109.2 psi

As b/12t<Fa Shell is Safe In Compression

8.4) Shell Compression For Anchored Tanks Per API 620 Appendix. L.5.2

The Maximum Longitudinal Compressive Force at The Bottom Of The ShellSo,

b =

= 1,260.68 lbs/ft8.5) Maximum Allowable Shell Compression For Anchored TaPer API 620 Appendix. L.5.3

D2(Wt+WL)

Wt {Weight of Roof + Weight Of Shell}/p x D

Wt + 1.273 x M s

D2

GHD2

t2

GHD2

t2

Fa + 600 (GH)0.5

Wt + 1.273 x M s

D2

b/12t = Maximum Longitudinal Compressive Stress= 166.78 psi

Now,

< 1.00E+06

So,

= 11486

As GHD2/t2<1000000 Use Fa=(1000000*t/2.5*D)+600*sqrt(GH)

Therefore,

= 1000000 x t

2.5 x D= 22109.2 psi

As b/12t<Fa Shell is Safe In Compression

9) Uplift Load Cases As Per API 650 Table 3-21a

P = Design Pressure in inch of water Column 28.0952

= Test Pressure in inch of water column 35.119

= Roof Plate thickness in inches 0.551

= Wind Moment in ft-lbs 19530

= Seismic Moment in ft-lbs 76,077

= Dead Load Of shell minus any corrosion all 16,426 any dead load other than roof plate acting on the shellminus any corrosion allowance in lbs

= Dead Load Of shell minus any corrosion all 18,145 any dead load including roof plate acting on the shellminus any corrosion allowance in lbs

= Dead Load Of shell using as built thicknesse 29004any dead load other than roof plate acting on the shellusing as built thicknesses in lbs

GHD2

t2

GHD2

t2

Fa + 600 (GH)0.5

Pt

th

Mw

Ms

W1

W2

W3

Note = The Allowable Tension Stresses are Taken From Table 5-7of API 620

Material = A36

Fy = 36000 psi From Table 1 of B55-E01

UPLIFT LOAD CASES NET UPLIFT F(lbf)

Design Pressure 217 15300

Test Pressure 5153 20349

Wind Load -12192.06 28800

Seismic Load 5043.39 28800

Design Pressure + Wind 6170 20349

Design Pressure + Seismic 23405 20349

UPLIFT LOAD CASES

Design Pressure 0.00025 0.16Test Pressure 0.00452 2.92Wind Load -0.00756 -4.88Seismic Load 0.00313 2.02Design Pressure + Wind 0.00541 3.49Design Pressure + Seismic 0.02054 13.25

No Of Anchor Bolt Provided N 56

Max. Required Bolt Area 0.02054

Bolt Area Provided 3.25 (Providing 2.25" anchor bolt area by consideringthe corrosion allowance of 1/4"on the dia)

Dia Of Anchor Bolt d 2.5 inch

Bolt Circle Dia 20240 mm

Bolt Spacing 1135 mmValue of Area is obtained from Table II of B55-E01

As Aprov.>Areq. Anchor Bolt Is Safe.

10) Anchor Chair CalculationsAs Per AISI E-1, Volume II Part VII

Fall For Anchor Bolts (PSI)

((P - 8th) x D2 x 4.08) - W1

((Pt - 8th) x D2 x4.08) - W1

(4 x Mw / D) - W2

(4 x Ms / D) - W2

((P - 8th) x D2 x 4.08) + (4 x Mw / D) - W1

((P - 8th) x D2 x 4.08) + (4 x Ms / D) - W1

Reqd. Bolt Area Ar = tb/Fall (in2)

Reqd. Bolt Area

Areq. inch2

Aprov. inch2

Top Plate Thickness C =

Critical Stress b/w the hole and S = 21 ksiand the free edge of plateDistance from outside of the f = 2.67 inchtop plate to edge of the hole

Distance b/w gussett plates g = 3.93 inch

Anchor Bolt Diameter d = 2.5 inch

Design Load Or Maximum P = 1 kipsAllowable load or 1.5 times the actual bolt load whichever is lesser

So,Top Plate Thickness C = 0.10 inch

2.58 mmActual Used Plate Thickness C = 30 mm

Thickness Provided Is OK

Anchor Chair Height Calculations

=

Reduction Factor Z =

Top Plate Width a = 13.77 inch

Anchor Chair Height h = 22 inch

Nominal Shell Radius R = 79 inch

[P(0.375g-0.22d)/Sf]0.5

Sinduced Pe[{1.32*Z/(1.43*a*h2/Rt)+(4ah2)0.333}+{0.031/(Rt)0.5}] t2

1/[{0.177am(m/t)2/(Rt)0.5}+1]

Shell Thickness Corroded t = 0.378 inch

Bottom Plate Thickness Corr. m = 0.142 inch

Anchor Bolt Accentricity e = 4.01 inch

Allowable Stress = 25 ksi

So,Z = 0.991

= 0.17 ksi

Gussett Plate Thickness Calculations

Gussett Plate Thickness = 0.04(h-C)

= 0.83 inch= 21.152 mm

Actual Gussett Plate Thickness J = 30

Gussett Plate Thickness Is Adequate

Now

J x K P/25 =J = 1.181 in

Average Width of Gussett = K = 5.118 in

J x K = 6.045P/25 = 0.0251

OK

11) Foundation Loading Data

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

Live load transferred to foundation

Live Load on roof = 25 psf

Area Of Roof = 20256

Total Live Load = 3517 lbs

Circimference of tank C = 41 ft

Sallowable

Sinduced

Jmin

³

Ar inch2

Live Load Transferred = 85 lbs/ftto foundation

Dead load transferred to foundation

Self Weight Of Shell Ws = 26004 lbs

Self Weight Of Shell Wr = 3163 lbs

Self Weight Of Bottom = 2307 lbsincluding annular plate

Weight of accessories = 3000 lbs

Toatal Dead Load = 32167 lbsActing On Shell

Dead Load Transferred = 778 lbs/ftto foundation

Operating & Hydrostatic Test Loads

Self weight of tank = 34474 lbs

Weight of contents in = 211777 lbsoperating condition

Weight Of Water = 249,345 lbsin hydrotest condition

Uniform Load In = 36039operating condition

Uniform Load In = 283,819 test condition

Wind Load Transferred to Foundation

Base Shear Due to = 2588 lbswind load

Reaction Due To = 36 lbs/ftWind Load

LL

Wb

Wa

WD

DL

Self Wt + Fluid=Wo lbs/ft2

Self Wt+Water=Wh lbs/ft2

Fw

Rw

Moment Due to = 19530 lbs-ftwind load

Seismic Load Transferred to Foundation

Base Shear Due to = 10083 lbsSeismic load

Reaction Due To = 140 lbs/ftSeismic Load

Moment Due to = 76,077 lbs-ftSeismic load

Summary of Foundation Loading Data

Dead Load 778 lbs/ftLive Load 85 lbs/ftUniform Load Operating Condition 36039uniform Load Test Condition 283,819 Base Shear Due TO wind Load 2588 lbsReaction Due To Wind Load 36 lbs/ftMoment Due To Wind Load 19530 lbs-ftBase Shear Due TO Seismic Load Fs 10083 lbsReaction Due To Seismic Load Rs 140 lbs/ftMoment Due To Seismic Load Ms 76,077 lbs-ft

Mw

Fs

Rs

Ms

DL

LL

WO lbs/ft2

Wh lbs/ft2

Fw

Rw

Mw

of the tank. Pg is the positive except in computation used to investigatethe ability of the tank to withstand a partial vacuum; in such

Meridional unit force in lbs/inch of latitudinal arc, in the wall of the tank

Latitudinal unit force in lbs/in of maridional arc, in the wall of the tankunder consideration. T2 is positive when in tension.(in cylinderical side walls the latitudinal unit forces are circumfrential unit forces)

Radius of curvature of the tank side wall in inch in a meridional plane

Length in inch of the normal to the tank wall at the level under consideration measured from the wall of the tank to the axis of the

Total weight in lbs of that portion of the tank and its contents(eitherabove the level under consideration, as in figure 5-4 panel b, orbelow it, as in figure 5-4 panel a) that is treated as a free body on the computations for that level. Strictly speaking the total weight would include the weight of all metal, gas and liquid in the portion of thetank treated as described; however the gas weight is negligible andthe metal weight may be negligible compared with the liquid weight.W shall be given the same sign as P when it acts in the same

acting at a given level of the tank under the

resulting from the liquid head at the level under

above the surface of the liquid. Thwe maximum) is the nominal pressure rating

is to be considered negativewhen it is on the side of the tank wall opposite from R2 except

is always positive except as provided in 5.10.2.6

direction as the pressure on the horizontal face of the free body;it shall be given the opposite sign when it acts in the opposite

Thickness in inch of the side walls, roof or bottom of the tank

Sulphuric Acid

Mpapsi

psipsfpsi

mmft

mmft

Mpapsi

mm

of the side walls, roof or bottom of the tank

Maximum allowable stress for simple tension in lbs/in2 as given in

established as prescribed

API 620 10TH Ed. ADD.01

Kg/m3

lbs/ft3

Kg/m3

lbs/ft3

OC

inchmminchmminch

mmft

mmft

mmft

inchmm

ftlbslbs

mph

psi0

( 0.8D TO 1.2D)

lbf

in2

ft2

B

lbf

(force acting in downward direction)

Equation 8 of 5.10.2.5


in2

ft2



Solving By Equation 18 of API 620


Psi



Psi

#DIV/0!

for this purpose, by considering the roof segment of 700mm diamter which is equivelant to 0.4 meter squre

, roof live loads shall not be less than concentrated load of 225 Kgs over 0.4

Internal Pressure + Pressure due to liquid head



Now following the above mentioned procedure for the calculation of remaining shell courses.

Weights Weights corroded

lbs Kgs

8,537 2,318 7,470 1,835 6,403 1,352 3,594 585 - - - - 26,004 corroded weig

lbs

453,808 330,271 206,735 83,198 - -

211,777

lbs

278,512 202,098 126,750 52,470 3,163 3,163

lbs/inch

1,933.49 1,416.82

902.31 389.96

-

Weight of Contents

Total Weight WHydrotest

T1

-

lbs/inch

1,933.49 1,416.82 915.69

416.27 - -

T{Max.(T1,T2)}

by using eq.18

326720481112459

14521452

Width in inch of roof consider to participate in resisting the circumfrential forces acting on the compression ring region.

Length in inch of the normal to the roof at the juncture b/wthe roof and the shell measured from the roof to the tank

[1342(tprov-C.A)]2/Rc

Provided thickness and the compression area is sufficient compared with values, achieved, based on API 620.

.x Bottom Area + tprov x Annular Area)

Vertical Distance b/w the intermediate wind girder and the topof the shell or in the case of the formad head the vertical distance b/w the intermediate wind girder and the head bend line plus

The thickness of the top shell course as ordered condition

psf

psf

psf

/S X E)0.5 + C.A

-[{tprov. - C.A}/OD}2 X {S X E/C} + Pbottom]

psf

psf

(after multiplying with load factor)

Thickness Of Top Shell Course as ordered condition in inch.

Thickness Of Shell Course for which transposed width is being calculated as ordered condition in inch.

inch

ft

inch

ft

inch

ft

inch

ft

inch

ft

inch

ft

ft

km/hr

ftm

m/sec

0.6013 x Kz x Kzt x Kd x V2 X I/1000

KN/m2

x D0 x qf x Cf x Ht

KN-m

lbs-ft

(Corroded)

(Corroded)

Uplift is graeter than shell and roof weight

(Ws' + Wr' - Uplift Due to Internal Pressure)

+ C2 x W2 x X2}

Height From The Bottom Of Tank Shell To The Shell Centre Of Gravity

Per API 620 Appendix. L.5.1




inch

ft-lbs

ft-lbs

lbs

lbs

lbs

inch of H2O

inch of H2O

15300 3.88

20349 92.01

28800 -217.72

28800 90.06

20349 110.18

20349 417.95

(Providing 2.25" anchor bolt area by consideringthe corrosion allowance of 1/4"on the dia)

all For Anchor Bolts (PSI)

tb = U / N Load / Anchor

[{1.32*Z/(1.43*a*h2/Rt)+(4ah2)0.333}+{0.031/(Rt)0.5}]

1/[{0.177am(m/t)2/(Rt)0.5}+1]

0.025

11 KN/m1 KN/m

1726 13,589

12 KN1 KN/m

26 KN-m45 KN

2 KN/m 103 KN-m

KN/m2

KN/m2

Weights corroded

lbs

5,110 4,045 2,981 1,290 - - 13,426

lbs lbs

249,345 482,975 705896.6275 181,468 350,901 113,591 219,894 45,713 89,955 - 3,163 - 3,163

Psi Psi Psi Psi

24.80 14.30 49.11 28.37 18.02 10.38 35.99 20.96 11.29 6.51 22.92 13.61 4.62 2.69 9.90 6.31 0.16 0.16 1.18 1.43 0.16 0.16 1.18 1.43

lbs/inch lbs/inch lbs/inch

1,116.91 1,914.53 1,107.93 825.25 1,415.11 833.52

535.75 915.69 559.11 248.41 416.27 284.71

- - -

Weight of Water

Total Weight W

W/At W/AthydroPcon.+W/At internal

Phydro+W/At Hydrotest

T1hydro T2 T2hydro

- - -

lbs/inch inch inch inch inch

1,116.91 0.17 0.35 OK OK

833.52 0.13 0.33 OK OK

559.11 0.08 0.30 OK OK

284.71 0.04 0.28 OK OK

- - 0.25 Not OK Not OK

- - 0.25 Not OK Not OK

T{Max.(T1hyd.,T2hyd.)}

tcalc. thydro tcalc<tprov. thydro<tprov.

by using eq.18Rc/2+W/At Rc/2 0.8*Rc (Rc/2+0.8*Rc) P

3201.20 66.1 -39.37007874 -62.99212598 -102.3622047 -31.271998.90 48.8 -39.37007874 -62.99212598 -102.3622047 -19.531078.07 33.7 -39.37007874 -62.99212598 -102.3622047 -10.53

438.69 20.8 -39.37007874 -62.99212598 -102.3622047 -4.291438.61 13.5 -39.37007874 -62.99212598 -102.3622047 -14.051438.61 13.5 -39.37007874 -62.99212598 -102.3622047 -14.05

[1342(tprov-C.A)]2/Rc-Rc/2+W/At

Documents

Calculation API 650