# SIST-TP CEN/TR 13121-5:2018

(Main)## GRP tanks and vessels for use above ground - Part 5: Example calculation of a GRP-vessel

## GRP tanks and vessels for use above ground - Part 5: Example calculation of a GRP-vessel

This Technical Report gives guidance for the design of a vessel using the standard EN 13121-3 GRP tanks and vessels for use above ground. The calculation is done according to the advanced design method given in EN 13121-3:2016, 7.9.3 with approved laminates and laminate properties.

## Oberirdische GFK-Tanks und -Behälter - Teil 5: Berechnungsbeispiel für einen Behälter aus GFK

Dieser Technische Report enthält eine Anleitung für die Bemessung eines Behälters nach EN 13121 3. Die Berechnung erfolgt nach dem in EN 13121 3:2016, 7.9.3, angegebenen fortgeschrittenen Bemessungs-verfahren mit geprüften Laminaten und statistisch abgesicherten Laminateigenschaften.

## Nadzemni rezervoarji in posode iz umetnih mas, ojačanih s steklenimi vlakni - 5. del: Primer izračuna

To tehnično poročilo vsebuje smernice za projektiranje posode na podlagi uporabe standarda EN 13121-3 za cisterne in posode GRP za uporabo nad tlemi. Izračun se izvede v skladu z naprednim načinom projektiranja, navedenim v standardu EN 13121-3:2016, 7.9.3, z odobrenimi laminati in lastnostmi laminatov.

### General Information

### Standards Content (Sample)

SLOVENSKI STANDARD

SIST-TP CEN/TR 13121-5:2018

01-maj-2018

1DG]HPQLUH]HUYRDUMLLQSRVRGHL]XPHWQLKPDVRMDþDQLKVVWHNOHQLPLYODNQL

GHO3ULPHUL]UDþXQD

GRP tanks and vessels for use above ground - Part 5: Example calculation of a GRP-

vessel

Ta slovenski standard je istoveten z: CEN/TR 13121-5:2017

ICS:

23.020.10 1HSUHPLþQHSRVRGHLQ Stationary containers and

UH]HUYRDUML tanks

SIST-TP CEN/TR 13121-5:2018 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST-TP CEN/TR 13121-5:2018

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SIST-TP CEN/TR 13121-5:2018

CEN/TR 13121-5

TECHNICAL REPORT

RAPPORT TECHNIQUE

May 2017

TECHNISCHER BERICHT

ICS 23.020.10

English Version

GRP tanks and vessels for use above ground - Part 5:

Example calculation of a GRP-vessel

This Technical Report was approved by CEN on 18 April 2017. It has been drawn up by the Technical Committee CEN/TC 210.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,

Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,

Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,

Turkey and United Kingdom.

EUROPEAN COMMITTEE FOR STANDARDIZATION

COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels

© 2017 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TR 13121-5:2017 E

worldwide for CEN national Members.

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SIST-TP CEN/TR 13121-5:2018

CEN/TR 13121-5:2017 (E)

Contents Page

European foreword . 5

Introduction . 6

1 Scope . 7

2 General . 7

3 Dimensions of the tank . 7

4 Building materials . 9

5 Loadings (9) . 9

6 Limit strain for laminate (8.2.2) . 11

7 Influence factors (7.9.5.2) . 11

8 Partial safety factors (Table 12) . 12

9 Combination factors (Table 11) . 12

10 Analysis of the cylinder . 12

10.1 Influence factor A . 12

5

10.2 Characteristic strength values . 13

10.3 Moduli of elasticity . 13

10.4 Analysis of the cylinder in axial direction . 13

10.4.1 Proof of strength (Ultimate limit state) . 14

10.4.2 Proof of strain (Serviceability limit state) . 17

10.4.3 Stability proof (Ultimate limit state) . 19

10.5 Analysis of the cylinder in tangential direction . 21

10.5.1 Strength analysis (Ultimate limit state) . 21

10.5.2 Proof of strain (Serviceability limit state) . 23

10.5.3 Stability proof for the cylindrical shell tangential (Ultimate limit state) . 23

10.5.4 Critical buckling pressure for rings (Ultimate limit state) . 24

10.6 Earthquake design of the cylinder . 26

10.6.1 Analysis of the cylinder in axial direction . 26

10.6.2 Analysis of the cylinder in tangential direction . 29

11 Opening in the cylinder . 30

11.1 Analysis in circumferential direction . 31

11.1.1 Proof of strength . 31

11.1.2 Proof of strain . 31

11.2 Analysis in axial direction . 32

11.2.1 Proof of strength . 32

11.2.2 Proof of strain . 32

12 Analysis of the skirt . 33

12.1 Internal forces of the skirt . 33

12.2 Proof of strength (Ultimate limit state) . 34

12.2.1 Design value of actions . 34

12.2.2 Design value of corresponding resistance . 34

12.2.3 Verification . 35

12.3 Proof of strain (Serviceability limit state) . 35

12.3.1 Design value of actions . 35

2

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CEN/TR 13121-5:2017 (E)

12.3.2 Limit design value of serviceability criterion. 35

12.3.3 Verification . 35

12.4 Stability proof (Ultimate limit state) . 35

12.4.1 Design value of actions . 35

12.4.2 Design value of corresponding resistance . 36

12.4.3 Verification . 36

12.5 Earthquake design of the skirt . 36

12.5.1 Internal forces Earthquake . 36

12.5.2 Proof of strength (Ultimate limit state) . 37

12.5.3 Proof of strain (Serviceability limit state) . 37

12.5.4 Stability proof (Ultimate limit state) . 38

13 Overlay laminate connection skirt - vessel . 39

13.1 Proof of strength (Ultimate limit state) . 39

13.1.1 Design value of actions . 39

13.1.2 Design value of corresponding resistance . 40

13.1.3 Verification . 40

13.2 Proof of strain (Serviceability limit state) . 40

13.2.1 Design value of actions . 40

13.2.2 Limit design value of serviceability criterion. 40

13.2.3 Verification . 40

13.3 Seismic design of the skirt overlay . 41

13.3.1 Proof of strength (Ultimate limit state) . 41

13.3.2 Proof of strain (Serviceability limit state) . 41

14 Analysis of the bottom . 42

14.1 Influence factor A . 42

5

14.2 Characteristic strength values . 42

14.3 Moduli of elasticity . 42

14.4 Actions, which cause internal forces for the bottom . 42

14.5 Strength analysis (Ultimate limit state) . 42

14.5.1 Design value of actions . 42

14.5.2 Proof of strain (Serviceability limit state) . 44

14.5.3 Stability proof of the bottom (Ultimate limit state) . 45

15 Lower part of the cylinder (Region 1) . 46

15.1 Strength analysis (Ultimate limit state) . 46

15.1.1 Design value of corresponding resistance . 47

15.1.2 Verification . 47

15.2 Proof of strain (Serviceability limit state) . 47

15.2.1 Design value of actions . 47

15.2.2 Limit design value of serviceability criterion. 47

15.2.3 Verification . 47

15.3 Earthquake design of region 1 (Ultimate limit state) . 48

15.3.1 Strength analysis (Ultimate limit state) . 48

15.3.2 Proof of strain (Serviceability limit state) . 48

16 Upper part of the skirt (Region 2) . 49

16.1 Strength analysis (Ultimate limit state) . 49

16.1.1 Design value of corresponding resistance . 50

16.1.2 Verification . 50

16.2 Proof of strain (Serviceability limit state) . 50

16.2.1 Design value of actions . 50

16.2.2 Limit design value of serviceability criterion. 50

16.2.3 Verification . 50

3

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16.3 Seismic design of region 2 (Ultimate limit state) . 51

16.3.1 Strength analysis (Ultimate limit state) . 51

16.3.2 Design value of corresponding resistance . 51

16.3.3 Verification . 51

16.4 Proof of strain (Serviceability limit state) . 51

16.4.1 Design value of actions . 51

16.4.2 Limit design value of serviceability criterion . 51

16.4.3 Verification . 52

17 Flange design . 52

18 Anchorage . 57

18.1 Anchorage for wind loads (Permanent / Transient situation) . 57

18.1.1 Uplifting anchor force . 57

18.1.2 Anchor shear force. 57

18.2 Anchorage for seismic loads (Seismic design situation) . 57

18.2.1 Uplifting anchor force . 57

18.2.2 Anchor shear force. 58

4

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CEN/TR 13121-5:2017 (E)

European foreword

This document (CEN/TR 13121-5:2017) has been prepared by Technical Committee CEN/TC 210 “GRP

tanks and vessels”, the secretariat of which is held by SFS.

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent

rights.

5

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Introduction

EN 13121 consists of the following parts:

— EN 13121-1, GRP tanks and vessels for use above ground — Part 1: Raw materials — Specification

and acceptance conditions

— EN 13121-2, GRP tanks and vessels for use above ground — Part 2: Composite materials — Chemical

resistance

— EN 13121-3, GRP tanks and vessels for use above ground — Part 3: Design and workmanship

— EN 13121-4, GRP tanks and vessels for use above ground — Part 4: Delivery, installation and

maintenance

— CEN/TR 13121-5, GRP tanks and vessels for use above ground — Part 5: Example calculation of a

GRP-tank (this report)

These five parts together define the responsibilities of the tank or vessel manufacturer and the

materials to be used in their manufacture.

EN 13121-1 specifies the requirements and acceptance conditions for the raw materials - resins, curing

agents, thermoplastics linings, reinforcing materials and additives. These requirements are necessary in

order to establish the chemical resistance properties determined in EN 13121-2 and the mechanical,

thermal and design properties determined in EN 13121-3. Together with the workmanship principles

determined in Part 3, requirements and acceptance conditions for raw materials ensure that the tank or

vessel will be able to meet its design requirements. EN 13121-4 of this standard specifies

recommendations for delivery, handling, installation and maintenance of GRP tanks and vessels. This

part of EN 13121 gives guidance in use of the standard. CEN/TC 210 has found it necessary to publish

an example calculation of a vessel according to EN 13121-3 due to the standards complexity, and for the

understanding of how the standard complies with EN 1990:s principles and requirements for safety,

serviceability and durability of structures.

The design and manufacture of GRP tanks and vessels involve a number of different materials such as

resins, thermoplastics and reinforcing fibres and a number of different manufacturing methods. It is

implicit that vessels and tanks covered by this standard are made only by manufacturers who are

competent and suitably equipped to comply with all the requirements of this standard, using materials

manufactured by competent and experienced material manufacturers.

Metallic vessels, and those manufactured from other isotropic, homogeneous materials, are

conveniently designed by calculating permissible loads based on measured tensile and ductility

properties. GRP, on the other hand, is a laminar material, manufactured through the successive

application of individual layers of reinforcement. As a result there are many possible combinations of

reinforcement type that will meet the structural requirement of any one-design case. This allows the

designer to select the laminate construction best suited to the available manufacturing facilities and

hence be most cost effective.

6

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1 Scope

This Technical Report gives guidance for the design of a vessel using the standard EN 13121-3 GRP

tanks and vessels for use above ground. The calculation is done according to the advanced design

method given in EN 13121-3:2016, 7.9.3 with approved laminates and laminate properties.

2 General

Vessels or vessel structures may contain such structural elements or solutions for which this standard

does not provide sufficient guidance. In that case, other methods shall be used in order to obtain a safe

structure.

This example calculation is based on a pressurized GRP vessel with an internal diameter of D 3000 mm.

The cylindrical parts of the vessel are filament wound. Its bottom and roof are torispherical dished ends

that are hand laid up using mixed laminates. Protection against medium attack is obtained by a

chemical resistance layer (CRL).

The tank is located outdoors in a seismic area.

IMPORTANT – This example doesn’t cover all necessary verifications for the calculation of the GRP tank.

Additional verifications have to be performed for the roof, the upper cylinder, etc.

3 Dimensions of the tank

Sketch of the tank dimensions:

7

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General Dimensions:

Diameter: D = 3 000 mm

Total height: H = 8 000 mm

tot

Cylinder:

Thickness cylinder 1: t = t = 9,2 mm

Cyl,1 C1

Thickness cylinder 2: t = t = 11,7 mm

Cyl,2 C2

Thickness cylinder at roof: t = 30,0 mm

Z,R

Thickness cylinder at bottom: t = 46,1 mm

Z,B

Total cylinder length: l = 6 610 mm

Cyl.tot

Distance between stiffeners: l = 3700 mm l = 3303 mm

s.1 s.2

Thickness of the stiffener: t = 20 mm

S

8

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Width of the stiffener: b = 260 mm

S

Skirt:

Thickness skirt: t = 17,0 mm

Sk

Thickness overlay laminate: t = 7,0 mm

02

Height of the skirt: H = 890 mm

Sk

Roof:

Thickness calotte: t = 13,0 mm

R

Radius calotte: R = 3000 mm

R

Thickness knuckle roof: tRk = 30,0 mm

Radius knuckle: r = 300 mm

Rk

Height of the roof: H = 590 mm

R

Bottom:

Thickness calotte: t = 16,5 mm

B

Radius calotte: R = 3 000 mm

B

Thickness knuckle: t = 45,0 mm

Bk

Radius knuckle: r = 300 mm

Bk

Height of the bottom: H = 590 mm

B

4 Building materials

Resin type: UP-resin, Resin group 4

5 Loadings (9)

LC 1: Dead load

The assumed dead loads for the separate tank parts are:

2

Roof: W = 4 kN Area load: w = 0,57 kN/m

R,k R,k

Cylinder + rings: W = 19 kN

C,k

2

Bottom: W = 4 kN Area load: w = 0,57 kN/m

B,k B,k

Skirt: W = 3 kN

Sk

Total dead load of the vessel: W = 30 kN

tot

LC 2: Liquid filling

3

Density of the medium ρ = 1,30 kg/dm

liquid

Filling height h = 7 000 mm

liquid

3

Volume V = 52,0 m

LC 3: Long time design overpressure

2

Design pressure PS = 2,000 bar ≡ 0,20 N/mm

op.l

LC 4: Short time design overpressure

9

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2

Design pressure PS = 2,500 bar ≡ 0,25 N/mm

op.s

LC 5: Long time design negative pressure

2

Design pressure PS = 0,000 bar ≡ 0,00 N/mm

ep.l

LC 6: Short time design negative pressure

2

Design pressure PS = 0,050 bar ≡ 0,005 N/mm

ep.s

LC 7: Wind (9.2.2)

2

Peak velocity pressure q = 0,8 kN/m (EN 1991–1-4)

p

Force coefficient (cylindrical vessel) c = 0,8

f

External pressure arising from wind load:

p =0,6⋅=q 0,6⋅0,8=0,48 kN/m²

wind p

LC 8: Snow (9.2.1)

2

Characteristic snow load s = 0,85 kN/m (EN 1991–1-3)

k

Shape coefficient μ = 0,80

Snow load

p = s⋅=µ 0,85⋅0,8=0,68 kN/m²

snow k

LC 9: Personnel loading (9.2.8)

2

Live load on the roof p = 1,5 kN/m

access

LC 10: Temperature

Design temperature TS = 50°C

Difference in temperature ΔT = 20 K

LC 11: Earthquake (9.2.3.4)

2

Reference peak ground a = 1,00 m/s

gR

acceleration

Importance factor γ = 1,4

1

Design ground acceleration

a a ⋅ γ 1,00⋅ 1, 4 1, 40 ms/²

g gR 1

Ground type according to D

EN 1998–1

Viscous damping 5 %

Control periods of the T = 0,20 s T = 0,8 s T = 2,0 s

B C D

response spectrum

Soil factor S = 1,35

Behaviour factor q = 1,5

2

Bending modulus cylinder E = 19 000 N/mm

ϕ,b

tangential

2

Bending modulus cylinder E = 12 000 N/mm

x,b

axial

Modulus of elasticity for

E=1,5⋅ E ⋅=E 1,5 ⋅ 19 000⋅ 12 000=22 650N / mm²

e φ,,b xb

short time impact

Cylinder thickness lower t approximately t = 17 mm

1/2 Sk

10

= = =

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third

Vibration period

2

ρ ⋅⋅h hh2

liquid liquid liquid liquid

T ⋅⋅D 0,,628⋅ + + 1 49

Et⋅ D D

e 12

2

1,33 ⋅⋅7200 7200 2 7200

T ⋅⋅3,,0 0 628⋅++ 1, 49 0,15 s

3

3000 3000

22650 ⋅⋅17,0 10

Design spectrum T ≤ T

C 25,,25

S T=a⋅ S⋅=1, 40⋅ 1,35⋅=3,15 ms/²

( )

D g

(plateau area):

q 1,5

Total mass of the vessel

W

30

tot

W +⋅V ρ + 52⋅ 1,30 70,66 Tonnen

(approximately)

G liquid

g 9, 81

Horizontal load (Base shear)

H ≅ S T⋅=W 3,15⋅ 70,66= 222,6 kN

( )

AE D G

Overturning moment

h

WH

liquid

tot tot

M ≅⋅ V ρ ⋅ + H − H + ⋅ ⋅ ST

( )

AE,tot liquid Sk B D

22g

7 000 8 000

30

−−33

M ≅⋅ 52 1,30 ⋅ + 800 − 590 ⋅ 10 + ⋅ ⋅ 10 ⋅ 3,15 =828,5 kNm

AE,tot

2 9, 81 2

6 Limit strain for laminate (8.2.2)

For the used UP resin is:

The roof is made of a mixed laminate ε = ε = 0,25 %

lim,R d,R

The bottom is made of a mixed laminate ε = ε = 0,25 %

lim,B d,B

The cylinder is made of a wound laminate 0° ε = ε = 0,20 % ε = ε = 0,27 %

lim,x,Cyl d,x,Cyl lim,ϕ,Cyl d,ϕ,Cyl

/90°

The skirt is made of a wound laminate 0° /90° ε = ε = 0,20 % ε = ε = 0,27 %

lim,x,Sk d,x,Sk lim,ϕ,Sk d,ϕ,Sk

7 Influence factors (7.9.5.2)

Influence factor A A = 1,0

1 1

Influence factor A A = 1,4 (Table A.4 of EN 13121–2)

2 2

Medium category 2, T = 50°C

d

HDT of the used resin HDT = 90 °C

Influence factor A

3

TS −°20 C 50 − 20

A 1,,00+ 0 4⋅ 1,,00+ 0 4⋅ 1,20

3

HDT −°30 C 90 − 30

Influence factor A A = 1,0

4 4

Influence factor A The influence factor A depends on laminate type and is selected separately

5 5

for each kind of laminate.

11

= = =

= = =

= =

=

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8 Partial safety factors (Table 12)

Situation

Action Symbol

P/T A/AE

Independent permanent actions (s.a): γ 1,35 1,00

G,sup

unfavourable γ 1,00 1,00

G,inf

favourable γ 1,35 1,00

G,sup

For liquid filling γ 0 0

G,inf

unfavourable γ 1,50 1,00

Q,sup

favourable γ 0 0

Q,inf

Independent variable actions: γ 1,00

A

unfavourable γ 1,00

AE

favourable

Accidental actions:

Seismic actions:

9 Combination factors (Table 11)

In the following table are shown the relevant Ψ-factors for this example.

Action ψ ψ ψ

0 1 2

Pressures: 1,0 1,0 1,0

- Long term pressures 0 0 0

- Short-term pressures

Imposed loads in buildings, category (see EN 1991–1-1) 0 0 0

- Category H: roofs

a)

Snow loads on buildings (see EN 1991–1-3) : 0,5 0,2 0

Remainder of CEN Member States,

- for sites located at altitude H ≤ 1000 m a.s.l.

Wind loads on buildings (see EN 1991–1-4) 0,6 0,2 0

Temperature (non-fire) in buildings (see EN 1991–1-5) 0,6

**...**

SLOVENSKI STANDARD

kSIST-TP FprCEN/TR 13121-5:2017

01-marec-2017

1DG]HPQLUH]HUYRDUMLLQSRVRGHL]XPHWQLKPDVRMDþDQLKVVWHNOHQLPLYODNQL

GHO3ULPHUL]UDþXQD

GRP tanks and vessels for use above ground - Part 5: Example calculation of a GRP-

vessel

Ta slovenski standard je istoveten z: FprCEN/TR 13121-5

ICS:

23.020.10 1HSUHPLþQHSRVRGHLQ Stationary containers and

UH]HUYRDUML tanks

kSIST-TP FprCEN/TR 13121-5:2017 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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kSIST-TP FprCEN/TR 13121-5:2017

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kSIST-TP FprCEN/TR 13121-5:2017

FINAL DRAFT

TECHNICAL REPORT

FprCEN/TR 13121-5

RAPPORT TECHNIQUE

TECHNISCHER BERICHT

December 2016

ICS 23.020.10

English Version

GRP tanks and vessels for use above ground - Part 5:

Example calculation of a GRP-vessel

This draft Technical Report is submitted to CEN members for Vote. It has been drawn up by the Technical Committee CEN/TC

210.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,

Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,

Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and

United Kingdom.

Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are

aware and to provide supporting documentation.

Warning : This document is not a Technical Report. It is distributed for review and comments. It is subject to change without

notice and shall not be referred to as a Technical Report.

EUROPEAN COMMITTEE FOR STANDARDIZATION

COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels

© 2016 CEN All rights of exploitation in any form and by any means reserved Ref. No. FprCEN/TR 13121-5:2016 E

worldwide for CEN national Members.

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kSIST-TP FprCEN/TR 13121-5:2017

FprCEN/TR 13121-5:2016 (E)

Contents Page

European foreword . 5

Introduction . 6

1 Scope . 7

2 General . 7

3 Dimensions of the tank . 7

4 Building materials . 9

5 Loadings (9) . 9

6 Limit strain for laminate (8.2.2) . 11

7 Influence factors (7.9.5.2) . 11

8 Partial safety factors (Table 12) . 12

9 Combination factors (Table 11) . 12

10 Analysis of the cylinder . 12

10.1 Influence factor A . 13

5

10.2 Characteristic strength values . 13

10.3 Moduli of elasticity . 13

10.4 Analysis of the cylinder in axial direction . 13

10.4.1 Proof of strength (Ultimate limit state) . 14

10.4.2 Proof of strain (Serviceability limit state) . 17

10.4.3 Stability proof (Ultimate limit state) . 19

10.5 Analysis of the cylinder in tangential direction . 21

10.5.1 Strength analysis (Ultimate limit state) . 21

10.5.2 Proof of strain (Serviceability limit state) . 23

10.5.3 Stability proof for the cylindrical shell tangential (Ultimate limit state) . 23

10.5.4 Critical buckling pressure for rings (Ultimate limit state) . 24

10.6 Earthquake design of the cylinder . 26

10.6.1 Analysis of the cylinder in axial direction . 26

10.6.2 Analysis of the cylinder in tangential direction . 29

11 Opening in the cylinder . 30

11.1 Analysis in circumferential direction . 31

11.1.1 Proof of strength . 31

11.1.2 Proof of strain . 31

11.2 Analysis in axial direction . 32

11.2.1 Proof of strength . 32

11.2.2 Proof of strain . 32

12 Analysis of the skirt . 32

12.1 Internal forces of the skirt . 33

12.2 Proof of strength (Ultimate limit state) . 34

12.2.1 Design value of actions . 34

12.2.2 Design value of corresponding resistance . 34

12.2.3 Verification . 35

12.3 Proof of strain (Serviceability limit state) . 35

12.3.1 Design value of actions . 35

2

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12.3.2 Limit design value of serviceability criterion. 35

12.3.3 Verification . 35

12.4 Stability proof (Ultimate limit state) . 36

12.4.1 Design value of actions . 36

12.4.2 Design value of corresponding resistance . 36

12.4.3 Verification . 36

12.5 Earthquake design of the skirt . 37

12.5.1 Internal forces Earthquake . 37

12.5.2 Proof of strength (Ultimate limit state) . 37

12.5.3 Proof of strain (Serviceability limit state) . 38

12.5.4 Stability proof (Ultimate limit state) . 39

13 Overlay laminate connection skirt - vessel . 39

13.1 Proof of strength (Ultimate limit state) . 39

13.1.1 Design value of actions . 39

13.1.2 Design value of corresponding resistance . 40

13.1.3 Verification . 40

13.2 Proof of strain (Serviceability limit state) . 40

13.2.1 Design value of actions . 40

13.2.2 Limit design value of serviceability criterion. 40

13.2.3 Verification . 41

13.3 Seismic design of the skirt overlay . 41

13.3.1 Proof of strength (Ultimate limit state) . 41

13.3.2 Proof of strain (Serviceability limit state) . 41

14 Analysis of the bottom . 42

14.1 Influence factor A . 42

5

14.2 Characteristic strength values . 42

14.3 Moduli of elasticity . 42

14.4 Actions, which cause internal forces for the bottom . 42

14.5 Strength analysis (Ultimate limit state) . 42

14.5.1 Design value of actions . 42

14.5.2 Proof of strain (Serviceability limit state) . 44

14.5.3 Stability proof of the bottom (Ultimate limit state) . 45

15 Lower part of the cylinder (Region 1) . 46

15.1 Strength analysis (Ultimate limit state) . 46

15.1.1 Design value of corresponding resistance . 47

15.1.2 Verification . 47

15.2 Proof of strain (Serviceability limit state) . 47

15.2.1 Design value of actions . 47

15.2.2 Limit design value of serviceability criterion. 47

15.2.3 Verification . 48

15.3 Earthquake design of region 1 (Ultimate limit state) . 48

15.3.1 Strength analysis (Ultimate limit state) . 48

15.3.2 Proof of strain (Serviceability limit state) . 49

16 Upper part of the skirt (Region 2) . 49

16.1 Strength analysis (Ultimate limit state) . 49

16.1.1 Design value of corresponding resistance . 50

16.1.2 Verification . 50

16.2 Proof of strain (Serviceability limit state) . 50

16.2.1 Design value of actions . 50

16.2.2 Limit design value of serviceability criterion. 50

16.2.3 Verification . 51

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16.3 Seismic design of region 2 (Ultimate limit state) . 51

16.3.1 Strength analysis (Ultimate limit state) . 51

16.3.2 Design value of corresponding resistance . 51

16.3.3 Verification . 51

16.4 Proof of strain (Serviceability limit state) . 51

16.4.1 Design value of actions . 51

16.4.2 Limit design value of serviceability criterion . 52

16.4.3 Verification . 52

17 Flange design . 52

18 Anchorage . 57

18.1 Anchorage for wind loads (Permanent / Transient situation) . 57

18.1.1 Uplifting anchor force . 57

18.1.2 Anchor shear force. 57

18.2 Anchorage for seismic loads (Seismic design situation) . 57

18.2.1 Uplifting anchor force . 57

18.2.2 Anchor shear force. 58

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European foreword

This document (FprCEN/TR 13121-5:2016) has been prepared by Technical Committee CEN/TC 210

“GRP tanks and vessels”, the secretariat of which is held by SFS.

This document is currently submitted to the Vote on TR.

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Introduction

EN 13121 consists of the following parts:

— EN 13121-1, GRP tanks and vessels for use above ground — Part 1: Raw materials — Specification

and acceptance conditions

— EN 13121-2, GRP tanks and vessels for use above ground — Part 2: Composite materials — Chemical

resistance

— EN 13121-3, GRP tanks and vessels for use above ground — Part 3: Design and workmanship

— EN 13121-4, GRP tanks and vessels for use above ground — Part 4: Delivery, installation and

maintenance

— CEN/TR 13121-5, GRP tanks and vessels for use above ground — Part 5: Example calculation of a

GRP-tank (this report)

These five parts together define the responsibilities of the tank or vessel manufacturer and the

materials to be used in their manufacture.

EN 13121-1 specifies the requirements and acceptance conditions for the raw materials - resins, curing

agents, thermoplastics linings, reinforcing materials and additives. These requirements are necessary in

order to establish the chemical resistance properties determined in EN 13121-2 and the mechanical,

thermal and design properties determined in EN 13121-3. Together with the workmanship principles

determined in Part 3, requirements and acceptance conditions for raw materials ensure that the tank or

vessel will be able to meet its design requirements. EN 13121-4 of this standard specifies

recommendations for delivery, handling, installation and maintenance of GRP tanks and vessels. This

part of EN 13121 gives guidance in use of the standard. CEN/TC 210 has found it necessary to publish

an example calculation of a vessel according to EN 13121-3 due to the standards complexity, and for the

understanding of how the standard complies with EN 1990:s principles and requirements for safety,

serviceability and durability of structures.

The design and manufacture of GRP tanks and vessels involve a number of different materials such as

resins, thermoplastics and reinforcing fibres and a number of different manufacturing methods. It is

implicit that vessels and tanks covered by this standard are made only by manufacturers who are

competent and suitably equipped to comply with all the requirements of this standard, using materials

manufactured by competent and experienced material manufacturers.

Metallic vessels, and those manufactured from other isotropic, homogeneous materials, are

conveniently designed by calculating permissible loads based on measured tensile and ductility

properties. GRP, on the other hand, is a laminar material, manufactured through the successive

application of individual layers of reinforcement. As a result there are many possible combinations of

reinforcement type that will meet the structural requirement of any one-design case. This allows the

designer to select the laminate construction best suited to the available manufacturing facilities and

hence be most cost effective.

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1 Scope

This Technical Report gives guidance for the design of a vessel using the standard EN 13121-3 GRP

tanks and vessels for use above ground. The calculation is done according to the advanced design

method given in EN 13121-3:2016, 7.9.3 with approved laminates and laminate properties.

2 General

Vessels or vessel structures may contain such structural elements or solutions for which this standard

does not provide sufficient guidance. In that case, other methods shall be used in order to obtain a safe

structure.

This example calculation is based on a pressurized GRP vessel with an internal diameter of D 3000 mm.

The cylindrical parts of the vessel are filament wound. Its bottom and roof are torispherical dished ends

that are hand laid up using mixed laminates. Protection against medium attack is obtained by a

chemical resistance layer (CRL).

The tank is located outdoors in a seismic area.

IMPORTANT – This example doesn’t cover all necessary verifications for the calculation of the GRP tank.

Additional verifications have to be performed for the roof, the upper cylinder, etc.

3 Dimensions of the tank

Sketch of the tank dimensions:

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General Dimensions:

Diameter: D = 3 000 mm

Total height: H = 8 000 mm

tot

Cylinder:

Thickness cylinder 1: t = t = 9,2 mm

Cyl,1 C1

Thickness cylinder 2: t = t = 11,7 mm

Cyl,2 C2

Thickness cylinder at roof: t = 30,0 mm

Z,R

Thickness cylinder at bottom: t = 46,1 mm

Z,B

Total cylinder length: l = 6 610 mm

Cyl.tot

Distance between stiffeners: l = 3700 mm l = 3303 mm

s.1 s.2

Thickness of the stiffener: t = 20 mm

S

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Width of the stiffener: b = 260 mm

S

Skirt:

Thickness skirt: t = 17,0 mm

Sk

Thickness overlay laminate: t = 7,0 mm

02

Height of the skirt: H = 890 mm

Sk

Roof:

Thickness calotte: t = 13,0 mm

R

Radius calotte: R = 3000 mm

R

Thickness knuckle roof: tRk = 30,0 mm

Radius knuckle: r = 300 mm

Rk

Height of the roof: H = 590 mm

R

Bottom:

Thickness calotte: t = 16,5 mm

B

Radius calotte: R = 3 000 mm

B

Thickness knuckle: t = 45,0 mm

Bk

Radius knuckle: r = 300 mm

Bk

Height of the bottom: H = 590 mm

B

4 Building materials

Resin type: UP-resin, Resin group 4

5 Loadings (9)

LC 1: Dead load

The assumed dead loads for the separate tank parts are:

2

Roof: W = 4 kN Area load: w = 0,57 kN/m

R,k R,k

Cylinder + rings: W = 19 kN

C,k

2

Bottom: W = 4 kN Area load: w = 0,57 kN/m

B,k B,k

Skirt: W = 3 kN

Sk

Total dead load of the vessel: W = 30 kN

tot

LC 2: Liquid filling

3

Density of the medium ρ = 1,30 kg/dm

liquid

Filling height h = 7 000 mm

liquid

3

Volume V = 52,0 m

LC 3: Long time design overpressure

2

Design pressure PS = 2,000 bar ≡ 0,20 N/mm

op.l

LC 4: Short time design overpressure

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2

Design pressure PS = 2,500 bar ≡ 0,25 N/mm

op.s

LC 5: Long time design negative pressure

2

Design pressure PS = 0,000 bar ≡ 0,00 N/mm

ep.l

LC 6: Short time design negative pressure

2

Design pressure PS = 0,050 bar ≡ 0,005 N/mm

ep.s

LC 7: Wind (9.2.2)

2

Peak velocity pressure q = 0,8 kN/m (EN 1991–1-4)

p

Force coefficient (cylindrical vessel) c = 0,8

f

𝑝 = 0,6∙𝑞 = 0,6∙ 0,8 = 0,48 𝑘𝑘/𝑚²

External pressure arising from wind load:

𝑤𝑤𝑤𝑤 𝑝

LC 8: Snow (9.2.1)

2

Characteristic snow load s = 0,85 kN/m (EN 1991–1-3)

k

Shape coefficient μ = 0,80

Snow load 𝑝 =𝑠 ∙𝜇 = 0,85∙ 0,8 = 0,68 𝑘𝑘/𝑚²

𝑘

𝑠𝑤𝑠𝑤

LC 9: Personnel loading (9.2.8)

2

Live load on the roof p = 1,5 kN/m

access

LC 10: Temperature

Design temperature TS = 50°C

Difference in temperature ΔT = 20 K

LC 11: Earthquake (9.2.3.4)

2

Reference peak ground a = 1,00 m/s

gR

acceleration

Importance factor γ = 1,4

1

Design ground acceleration

a a ⋅ γ 1,00⋅ 1, 4 1, 40 /²ms

g gR 1

Ground type according to D

EN 1998–1

Viscous damping 5 %

Control periods of the T = 0,20 s T = 0,8 s T = 2,0 s

B C D

response spectrum

Soil factor S = 1,35

Behaviour factor q = 1,5

2

Bending modulus cylinder E = 19 000 N/mm

ϕ,b

tangential

2

Bending modulus cylinder E = 12 000 N/mm

x,b

axial

Modulus of elasticity for

E=1,5⋅ E ⋅=E 1, 5⋅ 19 000⋅ 12 000=22 650N / mm²

e φ,,b xb

short time impact

Cylinder thickness lower t approximately t = 17 mm

1/2 Sk

third

10

= = =

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Vibration period

2

ρ ⋅⋅h hh2

liquid liquid liquid liquid

T ⋅⋅D 0,,628⋅ + + 1 49

Et⋅ D D

e 12

2

1,33 ⋅⋅7200 7200 2 7200

T ⋅⋅3,,0 0 628⋅++ 1, 49 0,15 s

3

3000 3000

22650 ⋅⋅17,0 10

Design spectrum T ≤ T

C 25,,25

S T=a⋅ S⋅=1, 40⋅ 1,35⋅=3,15 /²ms

( )

D g

(plateau area):

q 1,5

Total mass of the vessel

W

30

tot

W +⋅V ρ + 52⋅ 1,30 70, 66Tonnen

(approximately) G liquid

g 9, 81

Horizontal load (Base shear)

( ≅ S T⋅=W 3,15⋅ 70,66= 222,6 kN

( )

AE D G

Overturning moment

h

W(

liquid

tot tot

− ≅⋅ V ρ ⋅ + ( − ( + ⋅ ⋅ ST

( )

AE,tot liquid Sk B D

22g

7 000 8 000

30

−−33

− ≅⋅ ,52 1 30 ⋅ + 800 − 590 ⋅ 10 + ⋅ ⋅ 10 ⋅ 3,15 =828, 5 kNm

AE,tot

2 9, 81 2

6 Limit strain for laminate (8.2.2)

For the used UP resin is:

The roof is made of a mixed laminate ε = ε = 0,25 %

lim,R d,R

The bottom is made of a mixed laminate ε = ε = 0,25 %

lim,B d,B

The cylinder is made of a wound laminate 0° ε = ε = 0,20 % ε = ε = 0,27 %

lim,x,Cyl d,x,Cyl lim,ϕ,Cyl d,ϕ,Cyl

/90°

The skirt is made of a wound laminate 0° /90° ε = ε = 0,20 % ε = ε = 0,27 %

lim,x,Sk d,x,Sk lim,ϕ,Sk d,ϕ,Sk

7 Influence factors (7.9.5.2)

Influence factor A A = 1,0

1 1

Influence factor A A = 1,4 (Table A.4 of EN 13121–2)

2 2

Medium category 2, Td = 50°C

HDT of the used resin HDT = 90 °C

Influence factor A

3

TS −°20 C 50 − 20

A 1,,00+ 0 4⋅ 1,,00+ 0 4⋅ 1,20

3

(DT −°30 C 90 − 30

Influence factor A A = 1,0

4 4

Influence factor A The influence factor A depends on laminate type and is selected separately

5 5

for each kind of laminate.

11

= = =

= = =

= =

=

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8 Partial safety factors (Table 12)

Situation

Action Symbol

P/T A/AE

Independent permanent actions (s.a):

unfavourable γ 1,35 1,00

G,sup

favourable γ 1,00 1,00

G,inf

For liquid filling

unfavourable γ 1,35 1,00

G,sup

favourable γ 0 0

G,inf

Independent variable actions:

unfavourable γ 1,50 1,00

Q,sup

favourable γ 0 0

Q,inf

Accidental actions: γ 1,00

A

Seismic actions: γ 1,00

AE

9 Combination factors (Table 11)

In the following table are shown the relevant Ψ-factors for this example.

Action ψ ψ ψ

0 1 2

Pressures:

**...**

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