SIST EN 1993-4-2:2007
(Main)Eurocode 3 - Design of steel structures - Part 4-2: Tanks
Eurocode 3 - Design of steel structures - Part 4-2: Tanks
Part 4.2 of Eurocode 3 provides principles and application rules for the structural design of vertical cylindrical above ground steel tanks for the storage of liquid products with the following characteristics a) characteristic internal pressures above the liquid level not less than 100mbar and not more than 500mbar 1) ; b) design metal temperature in the range of 50ºC to +300ºC. For tanks constructed using austenitic stainless steels, the design metal temperature may be in the range of 165ºC to +300ºC. For fatigue loaded tanks, the temperature should be limited to T < 150ºC; c) maximum design liquid level not higher than the top of the cylindrical shell. This Part 4.2 is concerned only with the requirements for resistance and stability of steel tanks. Other design requirements are covered by EN 14015 for ambient temperature tanks and by EN 14620 for cryogenic tanks, and by EN 1090 for fabrication and erection considerations. These other requirements include foundations and settlement, fabrication, erection and testing, functional performance, and details like man-holes, flanges, and filling devices. Provisions concerning the special requirements of seismic design are provided in EN 1998-4 (Eurocode 8 Part 4 "Design of structures for earthquake resistance: Silos, tanks and pipelines"), which complements the provisions of Eurocode 3 specifically for this purpose. The design of a supporting structure for a tank is dealt with in EN 1993-1-1. The design of an aluminium roof structure on a steel tank is dealt with in EN 1999-1-5. Foundations in reinforced concrete for steel tanks are dealt with in EN 1992 and EN 1997. Numerical values of the specific actions on steel tanks to be taken into account in the design are given in EN 1991-4 "Actions on Silos and Tanks". Additional provisions for tank actions are given in annex A to this Part 4.2 of Eurocode 3. This Part 4.2 does not cover: floating roofs and floating covers; resistance to fire (refer to EN 1993-1-2). The circular planform tanks covered by this standard are restricted to axisymmetric structures, though they can be subject to unsymmetrical actions, and can be unsymmetrically supported.
Eurocode 3 - Bemessung und Konstruktion von Stahlbauten - Teil 4-2: Silos,Tankbauwerke und Rohrleitungen - Tankbauwerke
(1) Teil 4-2 von Eurocode 3 enthält verbindliche und nicht verbindliche Regeln für die Tragwerksbemessung von vertikalen, zylindrischen, oberirdischen Tankbauwerken aus Stahl zur Lagerung von Flüssigkeiten mit den folgenden Eigenschaften
charakteristischer Wert des Innendruckes oberhalb des Flüssigkeitsspiegels nicht kleiner als -100 mbar und nicht größer als 500 mbar );
a) Bemessungstemperatur für den Stahl im Bereich von -50 °C bis +300 °C. Für Tankbauwerke aus austenitischen nicht rostenden Stählen darf die Bemessungstemperatur im Bereich von -165 °C bis +300 °C liegen. Für dauerschwingbeanspruchte Tankbauwerke sollte die Temperatur auf T < 150 °C begrenzt werden;
b) Maximalen Auslegungsfüllhöhe nicht über dem oberen Rand des zylindrischen Mantels.
(2) Dieser Teil 4-2 behandelt nur die Anforderungen an Widerstand und Stabilität von Tankbauwerken aus Stahl. Sonstige Auslegungsanforderungen werden für Tankbauwerke bei Umgebungstemperatur in EN 14015 und für Tankbauwerke zur Lagerung tiefkalter Flüssigkeiten in EN 14620 sowie Betrachtungen zur Herstellung und Montage in EN 1090 behandelt. Diese sonstigen Anforderungen schließen Fundamente und Bodensetzung, Herstellung, Montage und Prüfung, Funktion und Details wie Mannlöcher, Flansche und Befüllvorrichtungen ein.
(3) Bestimmungen für die speziellen Anforderungen der Bemessung gegen Erdbeben sind in EN 1998 4 (Eurocode 8 Teil 4 Auslegung von Bauwerken gegen Erdbeben Silos, Tankbauwerke und Rohrleitungen) angegeben, die spezifisch für diesen Zweck die Bestimmungen von Eurocode 3 ergänzt.
(4) Die Bemessung einer Unterstützungskonstruktion von Tankbauwerken wird in EN 1993 1 1 behandelt.
(5) Die Bemessung einer Dachkonstruktion aus Aluminium für ein Tankbauwerk aus Stahl wird in EN 1999 1 5 behandelt.
(6) Stahlbetonfundamente für Tankbauwerke aus Stahl werden in EN 1992 und EN 1997 behandelt.
Eurocode 3 - Calcul des structures en acier - Partie 4-2: Réservoirs
Les Etats membres de l'UE et de l'AELE reconnaissent que les Eurocodes servent de documents de référence pour les usages suivants :
comme moyen de prouver la conformité de bâtiments et d'ouvrages de génie civil aux exigences essentielles de la Directive 89/106/CEE du Conseil, en particulier à l'Exigence essentielle N°1 Stabilité et Résistance mécaniques - et l'Exigence essentielle N°2 Sécurité en cas d'incendie ;
• comme base de spécification des contrats pour les travaux de construction et les services techniques associés ;
comme cadre d'établissement de spécifications techniques harmonisées pour les produits de construction (EN et ATE)
Les Eurocodes, dans la mesure où ils concernent les ouvrages de construction eux-mêmes, ont un lien direct avec les Documents interprétatifs ) auxquels il est fait référence dans l'Article 12 de la DPC, bien qu'ils soient de nature différente de celle des normes de produits harmonisées ). En conséquence, les aspects techniques résultant des travaux effectués pour les Eurocodes nécessitent d'être pris en considération de façon adéquate par les Comités techniques du CEN et/ou les Groupes de travail de l'EOTA travaillant sur les normes de produits en vue de parvenir à une complète compatibilité de ces spécifications techniques avec les Eurocodes.
Les normes Eurocodes donnent des règles de calcul structural communes en vue d'une utilisation quotidienne pour le calcul de structures entières et de composants, de nature tant traditionnelle qu'innovante. Les formes de construction ou les conceptions inhabituelles ne sont pas spécifiquement couvertes, et il appartiendra en ces cas au concepteur de se procurer des bases spécialisées supplémentaires.
Evrokod 3: Projektiranje jeklenih konstrukcij - 4-2. del: Rezervoarji
Del 4.2 evrokoda 3 določa načela in pravila za uporabo za konstrukcijsko zasnovo navpičnih valjastih jeklenih nadzemnih rezervoarjev za skladiščenje tekočih proizvodov z naslednjimi lastnostmi: a) značilni notranji tlak nad nivojem tekočine najmanj 100 mbar in največ 500 mbar 1); b) temperature projektiranih kovin v razponu od 50 °C do 300 °C. Pri rezervoarjih, projektiranih z uporabo avstenitnih nerjavnih jekel, je temperatura projektirane kovine lahko v razponu 165–300 ºC. Pri rezervoarjih z obremenitvijo z utrujanjem je temperaturo treba omejiti na T < 150 ºC; c) najvišji nivo tekočine ni višji od vrha cilindrične lupine. Ta del 4.2 se nanaša samo na zahteve za odpornost in stabilnost jeklenih rezervoarjev. Druge zahteve glede projektiranja so zajete v standardu EN 14015 za rezervoarje, projektirane za shranjevanje pri temperaturi okolja, standardu EN 14620 za kriogene rezervoarje ter standardu EN 1090 za izdelavo in postavitev. Te druge zahteve vključujejo temelje in posedanje, izdelavo, postavitev in preskušanje, funkcionalno zmogljivost ter podrobnosti, kot so vstopne odprtine, prirobnice in polnilne naprave. Določbe v zvezi s posebnimi zahtevami za potresnoodporno projektiranje so navedene v standardu EN 1998-4 (Del 4 evrokoda 8 »Projektiranje potresnoodpornih konstrukcij: Silosi, rezervoarji in cevovodi«), ki dopolnjuje določbe evrokoda 3 izključno za ta namen. Projektiranje podpornih struktur za rezervoarje je zajeto v standardu EN 1993-1-1. Projektiranje aluminijevih strešnih struktur na rezervoarjih je zajeto v standardu EN 1999-1-5. Temeljenje v armiranem betonu za jeklene rezervoarje je zajeto v standardih EN 1992 in EN 1997. Številčne vrednosti posameznih dejanj v povezavi z jeklenimi rezervoarji, ki se morajo upoštevati pri projektiranju, so navedene v standardu EN 1991-4 »Vplivi na konstrukcije – 4. del: Silosi in rezervoarji«. Dodatne določbe za dejanja v povezavi z rezervoarji so zajete v dodatku A k delu 4.2 evrokoda 3. Ta del 4.2 ne zajema naslednjih tem: plavajoče strehe in plavajoča prekrivala; protipožarna odpornost (glej EN 1993-1-2). Rezervoarji z okroglim tlorisom, ki jih zajema ta standard, so omejeni na aksisimetrične strukture, čeprav so lahko predmet nesimetričnih dejanj in so lahko nesimetrično podprti.
General Information
Relations
Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Evrokod 3: Projektiranje jeklenih konstrukcij - 4-2. del: RezervoarjiEurocode 3 - Bemessung und Konstruktion von Stahlbauten - Teil 4-2: Silos,Tankbauwerke und Rohrleitungen - TankbauwerkeEurocode 3 - Calcul des structures en acier - Partie 4-2: RéservoirsEurocode 3 - Design of steel structures - Part 4-2: Tanks91.080.10Kovinske konstrukcijeMetal structures91.010.30Technical aspects23.020.10UH]HUYRDUMLStationary containers and tanksICS:Ta slovenski standard je istoveten z:EN 1993-4-2:2007SIST EN 1993-4-2:2007en01-julij-2007SIST EN 1993-4-2:2007SLOVENSKI
STANDARDSIST ENV 1993-4-2:20011DGRPHãþD
SIST EN 1993-4-2:2007
EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 1993-4-2February 2007ICS 23.020.01; 91.010.30; 91.080.10Supersedes ENV 1993-4-2:1999
English VersionEurocode 3 - Design of steel structures - Part 4-2: TanksEurocode 3 - Calcul des structures en acier - Partie 4-2:RéservoirsEurocode 3 - Bemessung und Konstruktion vonStahlbauten - Teil 4-2: Silos,Tankbauwerke undRohrleitungen - TankbauwerkeThis European Standard was approved by CEN on 12 June 2006.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the CEN Management Centre or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36
B-1050 Brussels© 2007 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 1993-4-2:2007: ESIST EN 1993-4-2:2007
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Contents
Foreword 4 1 General 8 1.1 Scope 8 1.2 Normative references 8 1.3 Assumptions 10 1.4 Distinction between principles and application rules 10 1.5 Terms and definitions 10 1.6 Symbols used in Part 4.2 of Eurocode 3 12 1.7 Sign conventions 13 1.8 Units 18 2
Basis of design 19 2.1 Requirements 19 2.2 Reliability differentiation 19 2.3 Limit states 19 2.4 Actions and environmental effects 19 2.5 Material properties 19 2.6 Geometrical data 20 2.7 Modelling of the tank for determining action effects 20 2.8 Design assisted by testing 20 2.9 Action effects for limit state verifications 20 2.10 Combinations of actions 22 2.11 Durability 22 3 Properties of materials 23 3.1 General 23 3.2 Structural steels 23 3.3 Steels for pressure purposes 23 3.4 Stainless steels 23 3.5 Toughness requirements 24 4 Basis for structural analysis 25 4.1 Ultimate limit states 25 4.2 Analysis of the circular shell structure of a tank 25 4.3 Analysis of the box structure of a rectangular tank 27 4.4 Equivalent orthotropic properties of corrugated sheeting 28 5 Design of cylindrical walls 29 5.1 Basis 29 5.2 Distinction of cylindrical shell forms 29 5.3 Resistance of the tank shell wall 29 5.4 Considerations for supports and openings 30 5.5 Serviceability limit states 33 6 Design of conical hoppers 34 7 Design of circular roof structures 34 7.1 Basis 34 7.2 Distinction of roof structural forms 34 7.3 Resistance of circular roofs 35 7.4 Considerations for individual structural forms 35 SIST EN 1993-4-2:2007
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7.5 Serviceability limit states 36 8 Design of transition junctions at the bottom of the shell and supporting ring girders 36 9 Design of rectangular and planar-sided tanks 37 9.1 Basis 37 9.2 Distinction of structural forms 37 9.3 Resistance of vertical walls 37 9.4 Serviceability limit states 38 10 Requirements on fabrication, execution and erection with relation to design 38 11 Simplified design 39 11.1 General 39 11.2 Fixed roof design 40 11.3 Shell design 46 11.4 Bottom design 50 11.5 Anchorage design 51 Annex A [normative] 53 Actions on tanks 53 A.1 General 53 A.2 Actions 53
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Foreword This European Standard EN 1993-4-2, Eurocode 3: Design of steel structures: “Design of Steel Structures – Part 4-2: Tanks”, has been prepared by Technical Committee CEN/TC250 « Structural Eurocodes », the Secretariat of which is held by BSI. CEN/TC250 is responsible for all Structural Eurocodes.
This European Standard shall be given the status of a National Standard, either by publication of an identical text or by endorsement, at the latest by August 2007, and conflicting National Standards shall be withdrawn at latest by March 2010.
This Eurocode supersedes ENV1993-4-2: 1999.
According to the CEN-CENELEC Internal Regulations, the National Standard Organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
Background of the Eurocode programme In 1975, the Commission of the European Community decided on an action programme in the field of construction, based on article 95 of the Treaty. The objective of the programme was the elimination of technical obstacles to trade and the harmonisation of technical specifications. Within this action programme, the Commission took the initiative to establish a set of harmonised technical rules for the design of construction works which, in a first stage, would serve as an alternative to the national rules in force in the Member States and, ultimately, would replace them.
For fifteen years, the Commission, with the help of a Steering Committee with Representatives of Member States, conducted the development of the Eurocodes programme, which led to the first generation of European codes in the 1980’s.
In 1989, the Commission and the Member States of the EU and EFTA decided, on the basis of an agreement1)
between the Commission and CEN, to transfer the preparation and the publication of the Eurocodes to the CEN through a series of Mandates, in order to provide them with a future status of European Standard (EN). This links de facto the Eurocodes with the provisions of all the Council’s Directives and/or Commission’s Decisions dealing with European standards (e.g. the Council Directive 89/106/EEC on construction products - CPD - and Council Directives 93/37/EEC, 92/50/EEC and 89/440/EEC on public works and services and equivalent EFTA Directives initiated in pursuit of setting up the internal market). The Structural Eurocode programme comprises the following standards generally consisting of a number of Parts: EN1990 Eurocode 0: Basis of structural design EN1991 Eurocode 1: Actions on structures EN1992 Eurocode 2: Design of concrete structures
1) Agreement between the Commission of the European Communities and the European Committee for Standardisation (CEN) concerning the work on EUROCODES for the design of building and civil engineering works (BC/CEN/03/89). SIST EN 1993-4-2:2007
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EN1993 Eurocode 3: Design of steel structures EN1994 Eurocode 4: Design of composite steel and concrete structures EN1995 Eurocode 5: Design of timber structures EN1996 Eurocode 6: Design of masonry structures EN1997 Eurocode 7: Geotechnical design EN1998 Eurocode 8: Design of structures for earthquake resistance EN1999 Eurocode 9: Design of aluminium structures Eurocode standards recognise the responsibility of regulatory authorities in each Member State and have safeguarded their right to determine values related to regulatory safety matters at national level where these continue to vary from State to State. Status and field of application of Eurocodes The Member States of the EU and EFTA recognise that EUROCODES serve as reference documents for the following purposes:
as a means to prove compliance of building and civil engineering works with the essential requirements of Council Directive 89/106/EEC, particularly Essential Requirement N°1 - Mechanical resistance and stability - and Essential Requirement N°2 - Safety in case of fire ; · as a basis for specifying contracts for construction works and related engineering services ; · as a framework for drawing up harmonised technical specifications for construction products (ENs and ETAs) The Eurocodes, as far as they concern the construction works themselves, have a direct relationship with the Interpretative Documents2) referred to in Article 12 of the CPD, although they are of a different nature from harmonised product standards3). Therefore, technical aspects arising from the Eurocodes work need to be adequately considered by CEN Technical Committees and/or EOTA Working Groups working on product standards with a view to achieving full compatibility of these technical specifications with the Eurocodes. The Eurocode standards provide common structural design rules for everyday use for the design of whole structures and component products of both a traditional and an innovative nature. Unusual forms of construction or design conditions are not specifically covered and additional expert consideration will be required by the designer in such cases. National Standards implementing Eurocodes The National Standards implementing Eurocodes will comprise the full text of the Eurocode (including any annexes), as published by CEN, which may be preceded by a National title page and National foreword, and may be followed by a National Annex.
2) According to Art. 3.3 of the CPD, the essential requirements (ERs) shall be given concrete form in interpretative documents for the creation of the necessary links between the essential requirements and the mandates for harmonised ENs and ETAGs/ETAs. 3) According to Art. 12 of the CPD the interpretative documents shall : a) give concrete form to the essential requirements by harmonising the terminology and the technical bases and indicating classes or levels for each requirement where necessary ; b) indicate methods of correlating these classes or levels of requirement with the technical specifications, e.g. methods of calculation and of proof, technical rules for project design, etc. ; c) serve as a reference for the establishment of harmonised standards and guidelines for European technical approvals.
The Eurocodes, de facto, play a similar role in the field of the ER 1 and a part of ER 2. SIST EN 1993-4-2:2007
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The National Annex may only contain information on those parameters which are left open in the Eurocode for national choice, known as Nationally Determined Parameters, to be used for the design of buildings and civil engineering works to be constructed in the country concerned, i.e. : · values and/or classes where alternatives are given in the Eurocode, · values to be used where a symbol only is given in the Eurocode, · country specific data (geographical, climatic, etc), e.g. snow map, · the procedure to be used where alternative procedures are given in the Eurocode. It may also contain:
decisions on the application of informative annexes, · references to non-contradictory complementary information to assist the user to apply the Eurocode. Links between Eurocodes and harmonised technical specifications (ENs and ETAs) for products There is a need for consistency between the harmonised technical specifications for construction products and the technical rules for works4). Furthermore, all the information accompanying the CE Marking of the construction products which refer to Eurocodes should clearly mention which Nationally Determined Parameters have been taken into account. Additional information specific to EN1993-4-2 EN 1993-4-2 gives design guidance for the structural design of tanks. EN 1993-4-2 gives design rules that supplement the generic rules in the many parts of EN 1993-1. EN 1993-4-2 is intended for clients, designers, contractors and relevant authorities. EN 1993-4-2 is intended to be used in conjunction with EN 1990, with EN 1991-4, with the other Parts of EN 1991, with EN 1993-1-6 and EN 1993-4-1, with the other Parts of EN 1993, with EN 1992 and with the other Parts of EN 1994 to EN 1999 relevant to the design of tanks.
Matters that are already covered in those documents are not repeated. Numerical values for partial factors and other reliability parameters are recommended as basic values that provide an acceptable level of reliability. They have been selected assuming that an appropriate level of workmanship and quality management applies. Safety factors for ‘product type’ tanks (factory production) can be specified by the appropriate authorities.
When applied to ‘product type’ tanks, the factors in 2.9 are for guidance purposes only.
They are provided to show the likely levels needed to achieve consistent reliability with other designs. National Annex for EN1993-4-2 This standard gives alternative procedures, values and recommendations for classes with notes indicating where national choices may have to be made. Therefore the National Standard implementing EN 1993-4-2 should have a National Annex containing all Nationally Determined Parameters to be used for the design of buildings and civil engineering works to be constructed in the relevant country. National choice is allowed in EN 1993-4-2 through: – 2.2 (1) – 2.2 (3)
4) see Art.3.3 and Art.12 of the CPD, as well as clauses 4.2, 4.3.1, 4.3.2 and 5.2 of ID 1. SIST EN 1993-4-2:2007
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– 2.9.2.1 (1)P – 2.9.2.1 (2)P – 2.9.2.1 (3)P – 2.9.2.2 (3) P – 2.9.3 (2) – 3.3 (3) – 4.1.4 (3) – 4.3.1 (6) – 4.3.1 (8) SIST EN 1993-4-2:2007
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1 General 1.1 Scope (1) Part 4.2 of Eurocode 3 provides principles and application rules for the structural design of vertical cylindrical above ground steel tanks for the storage of liquid products with the following characteristics a) characteristic internal pressures above the liquid level not less than -100mbar and not more than 500mbar 1) ; b) design metal temperature in the range of -50ºC to +300ºC.
For tanks constructed using austenitic stainless steels, the design metal temperature may be in the range of -165ºC to +300ºC. For fatigue loaded tanks, the temperature should be limited to T < 150ºC; c) maximum design liquid level not higher than the top of the cylindrical shell. (2) This Part 4.2 is concerned only with the requirements for resistance and stability of steel tanks. Other design requirements are covered by EN 14015 for ambient temperature tanks and by EN 14620 for cryogenic tanks, and by EN 1090 for fabrication and erection considerations.
These other requirements include foundations and settlement, fabrication, erection and testing, functional performance, and details like man-holes, flanges, and filling devices.
(3) Provisions concerning the special requirements of seismic design are provided in EN 1998-4 (Eurocode 8 Part 4 “Design of structures for earthquake resistance: Silos, tanks and pipelines”), which complements the provisions of Eurocode 3 specifically for this purpose. (4) The design of a supporting structure for a tank is dealt with in EN 1993-1-1. (5) The design of an aluminium roof structure on a steel tank is dealt with in EN 1999-1-5. (6) Foundations in reinforced concrete for steel tanks are dealt with in EN 1992 and EN 1997. (7) Numerical values of the specific actions on steel tanks to be taken into account in the design are given in EN 1991-4 "Actions on Silos and Tanks".
Additional provisions for tank actions are given in annex A to this Part 4.2 of Eurocode 3.
(8) This Part 4.2 does not cover: - floating roofs and floating covers; - resistance to fire (refer to EN 1993-1-2). (9) The circular planform tanks covered by this standard are restricted to axisymmetric structures, though they can be subject to unsymmetrical actions, and can be unsymmetrically supported. 1.2 Normative references This European Standard incorporates, by dated and undated reference, provisions from other standards.
These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to, or revisions of, any of these publications apply to the European Standard only when incorporated in it by amendment or revision.
For undated references the latest edition of the publication referred to applies.
1) All pressures are in mbar gauge unless otherwise specified SIST EN 1993-4-2:2007
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EN 1090-2 Execution of steel and aluminium structures – Technical requirements for steel structures EN 1990 Eurocode:
Basis of structural design; EN 1991 Eurocode 1: Actions on structures; Part 1.1:
Actions on Structures - Densities, self weight and imposed loads for buildings; Part 1.2:
Actions on structures - Actions on structures exposed to fire; Part 1.3:
Actions on structures - Snow loads; Part 1.4:
Actions on structures - Wind loads; Part 4:
Actions on silos and tanks; EN 1992 Eurocode 2 : Design of concrete structures ; EN 1993 Eurocode 3: Design of steel structures; Part 1.1: General rules and rules for buildings; Part 1.3:
General rules - Supplementary rules for cold formed members and sheeting; Part 1.4: General rules – Supplementary rules for stainless steels; Part 1.6:
General rules - Supplementary rules for the strength and stability of shell structures; Part 1.7:
General rules - Supplementary rules for planar plated structures loaded transversely;
Part 1.10: Material toughness and through thickness properties; Part 4.1:
Silos; EN 1997 Eurocode 7: Geotechnical design; EN 1998 Eurocode 8: Design of structures for earthquake resistance; Part 4:
Silos, tanks and pipelines; EN 1999 Eurocode 9: Design of aluminium structures;
Part 1.5: Shell structures; EN 10025 Hot rolled products of non-alloy structural steels – technical delivery conditions; EN 10028 Flat products made of steel for pressure purposes; EN 10088 Stainless steels EN 10149 Specification for hot-rolled flat products made of high yield strength steels for cold forming.
Part 1:
General delivery conditions
Part 2: Delivery conditions for thermomechanically rolled steels
Part 3: Delivery conditions for normalized or normalized rolled steels
EN 13084 Freestanding industrial chimneys
Part 7: Product specification of cylindrical steel fabrications for use in single wall steel chimneys and steel liners EN 14015 Specification for the design and manufacture of site built, vertical, cylindrical, flat bottomed, above ground, welded, metallic tanks for the storage of liquids at ambient temperatures
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EN 14620
Design and manufacture of site built, vertical, cylindrical, flat-bottomed steel tanks for the storage of refrigerated, liquefied gases with operating temperatures between –5°C and –165°C; ISO 1000 SI Units; ISO 3898 Bases for design of structures – Notation – General symbols; ISO 8930 General principles on reliability for structures - List of equivalent terms.
1.3 Assumptions (1) In addition to the general assumptions of EN 1990 the following assumption applies:
- fabrication and erection complies with EN 1090, EN 14015 and 14620 as appropriate 1.4 Distinction between principles and application rules (1) See 1.4 in EN 1990.
1.5 Terms and definitions (1) The terms that are defined in 1.5 in EN 1990 for common use in the Structural Eurocodes and the definitions given in ISO 8930 apply to this Part 4.2 of EN 1993, unless otherwise stated, but for the purposes of this Part 4.2 the following supplementary definitions are given: 1.5.1
shell. A structure formed from a curved thin plate.
This term also has a special meaning for tanks: see 1.7.2. 1.5.2
axisymmetric shell. A shell structure whose geometry is defined by rotation of a meridional line about a central axis. 1.5.3
box.
A structure formed from an assembly of flat plates into a three-dimensional enclosed form.
For the purposes of this standard, the box has dimensions that are generally comparable in all directions. 1.5.4
meridional direction.
The tangent to the tank wall at any point in a plane that passes through the axis of the tank.
It varies according to the structural element being considered. 1.5.5
circumferential direction.
The horizontal tangent to the tank wall at any point.
It varies around the tank, lies in the horizontal plane and is tangential to the tank wall irrespective of whether the tank is circular or rectangular in plan. 1.5.6
middle surface.
This term is used to refer to both the stress-free middle surface when a shell is in pure bending and the middle plane of a flat plate that forms part of a box. 1.5.7
separation of stiffeners.
The centre to centre distance between the longitudinal axes of two adjacent parallel stiffeners. Supplementary to Part 1 of EN 1993 (and Part 4 of EN 1991), for the purposes of this Part 4.2, the following terminology applies: SIST EN 1993-4-2:2007
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1.5.8
tank.
A tank is a vessel for storing liquid products.
In this standard it is assumed to be prismatic with a vertical axis (with the exception of the tank bottom and roof parts). 1.5.9
shell.
The shell is the cylindrical wall of the tank of circular planform.
Although this usage is slightly confusing when it is compared to the definition given in 1.4.1, it is so widely used with the two meanings that both have been retained here.
Where any confusion can arise, the alternative term “cylindrical wall” is used. 1.5.10
tank wall.
The metal plate elements forming the vertical walls, roof or a hopper bottom are referred to as the tank wall.
This term is not restricted to the vertical walls. 1.5.11
course.
The cylindrical wall of the tank is formed making horizontal joints between a series of short cylindrical sections, each of which is formed by making vertical joints between individual curved plates.
A short cylinder without horizontal joints is termed a course. 1.5.12
hopper.
A hopper is a converging section towards the bottom of a tank.
It is used to channel fluids towards a gravity discharge outlet (usually when they contain suspended solids). 1.5.13
junction.
A junction is the point at which any two or more shell segments or flat plate elements meet.
It can include a stiffener or not: the point of attachment of a ring stiffener to the shell or box may be treated as a junction.
1.5.14
transition junction.
The transition junction is the junction between the vertical wall and a hopper.
The junction can be at the base of the vertical wall or part way down it. 1.5.15
shell-roof junction.
The shell-roof junction is the junction between the vertical wall and the roof.
It is sometimes referred to as the eaves junction, though this usage is more common for solids storages. 1.5.16
stringer stiffener.
A stringer stiffener is a local stiffening member that follows the meridian of a shell, representing a generator of the shell of revolution.
It is provided to increase the stability, or to assist with the introduction of local loads or to carry axial loads.
It is not intended to provide a primary load carrying capacity for bending due to transverse loads. 1.5.17
rib.
A rib is a local member that provides a primary load carrying path for loads causing bending down the meridian of a shell or flat plate, representing a generator of the shell of revolution or a vertical stiffener on a box.
It is used to distribute transverse loads on the structure by bending action. 1.5.18
ring stiffener.
A ring stiffener is a local stiffening member that passes around the circumference of the structure at a given point on the meridian.
It is assumed to have no stiffness in the meridional plane of the structure.
It is provided to increase the stability or to introduce local loads, not as a primary load-carrying element.
In a shell of revolution it is circular, but in rectangular structures is takes the rectangular form of the plan section. 1.5.19
base ring.
A base ring is a structural member that passes around the circumference of the structure at the base and is required to ensure that the assumed boundary conditions are achieved in practice. 1.5.20
ring girder or ring beam.
A ring girder or ring beam is a circumferential stiffener which has bending stiffness and strength both in the plane of the circular section of a shell or the plan section of a rectangular structure and also normal to that plane.
It is a primary load-carrying element, used to distribute local loads into the shell or box structure. SIST EN 1993-4-2:2007
EN 1993-4-2: 2007 (E)
12
1.5.21 continuously supported.
A continuously supported tank is one in which all positions around the circumference are supported in an identical manner.
Minor departures from this condition (e.g. a small opening) need not affect the applicability of the definition. 1.5.22
discrete support.
A discrete support is a position in which a tank is supported using a local bracket or column, giving a limited number of narrow supports around the tank circumference. 1.5.23
catch basin.
An external tank structure to contain fluid that may escape by leakage or accident from the primary tank.
This type of structure is used where the primary tank contains toxic or dangerous fluids. 1.6 Symbols used in Part 4.2 of Eurocode 3 The symbols used are based on ISO 3898:1987. 1.6.1 Roman upper case letters A
area of cross-section A1, A2
area of top, bottom flange of roof centre ring D
diameter of tank E
Young’s modulus H
height of part of shell wall to liquid surface; maximum design liquid height H0
height of the tank shell I
second moment of area of cross-section K
coefficient for buckling design L
height of shell segment or stiffener shear length M
bending moment in structural member N
axial force in structural member Nf
minimum number of load cycles relevant for fatigue P
vertical load on roof rafter R
radius of curvature of shell which is not cylindrical T
temperature W
elastic section modulus;
weight 1.6.2 Roman lower case letters
side length of a rectangular opening in the shell
b
side length of a rectangular opening in the shell; width of a plate element in a cross-section cp
coefficient for wind pressure loading d
diameter of manhole or nozzle e
distance of outer fibre of beam to beam axis fy
design yield strength of steel fu
ultimate strength of steel h
rise of roof (height of apex of a dome roof above the plane of its junction to the tank shell)
height of each course in tank shell
joint efficiency factor; stress concentration factor; count of shell wall courses l height of shell over which a buckle may form m
bending moment per unit width n
membrane stress resultant
number of rafters in circular tank roof
distributed loading (not necessarily normal to wall) pn
pressure normal to tank wall (outward) r
radius of middle surface of cylindrical wall of tank t
wall thickness SIST EN 1993-4-2:2007
EN 1993-4-2: 2007 (E)
13
w
minimum width of base ring annular plate x
radial coordinate for a tank roof y
local vertical coordinate for a tank roof; replacement factor used in design of reinforced openings z
global axial coordinate
coordinate along the vertical axis of an axisymmetric tank (shell of revolution) 1.6.3 Greek letters a
slope of roof b
inclination of tank bottom to vertical; = p/n where
n
is the number of rafters gF
partial factor for actions gM
partial factor for resistance
d
deflection D
change in a variable n
Poisson’s ratio q
circumferential coordinate around shell s
direct stress t
shear stress 1.6.4 Subscripts E value of stress or displacement (arising from design actions) F at half span; action a annular d design value f fatigue i inside; inward directed; counting variable k roof centre ring k characteristic value m mean value min minimum allowed value n nominal; normal to the wall o outside; outward directed p pressure r
radial; ring R resistance s at support s shell wall x meridional; radial; axial y circumferential; transverse; yield 0 reference value 1 upper 2 lower q
circumferential (shells of revolution)
1.7 Sign conventions 1.7.1 Conventions for global tank structure axis system for circular tanks (1) The sign convention given here is for the complete tank structure, and recognises that the tank is not a structural member.
Care with coordinate systems is required to ensure that local coordinates associated with members attached to the shell wall and loadings given in local coordinate directions but defined by a global coordinate are not confused. SIST EN 1993-4-2:2007
EN 1993-4-2: 2007 (E)
14
(2) In general, the convention for the global tank structure axis system is in cylindrical coordinates (see figure 1.1) as follows: Coordinate system Coordinate along the central axis of a shell of revolution z
Radial coordinate r Circumferential coordinate
q (3) The convention for positive directions is: Outward direction positive (internal pressure positive, outward displacements positive)
Tensile stresses positive
(except in buckling equations where compression is positive)
(4) The convention for distributed actions on the tank wall surface is: Pressure normal to shell (outward pressure) pn
D S BB
b p p r z T
P= pole; M= shell meridian; C= Instantaneous centre of meridional curvature a)
3D sketch with general axisymmetric sh
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