Eurocode 1 - Actions on structures - Part 4: Silos and tanks

(1)P   This part provides general principles and actions for the structural design of silos for the storage of particulate solids and tanks for the storage of fluids and shall be used in conjunction with EN 1990, other parts of EN 1991 and EN 1992 to EN 1999.
(2)   This part includes some provisions for actions on silo and tank structures that are not only associated with the stored solids or liquids (e.g. the effects of thermal differentials, aspects of the differential settlements of batteries of silos)
(3)   The following geometrical limitations apply to the design rules for silos:
-   the silo cross-section shapes are limited to those shown in Figure 1.1d, though minor variations may be accepted provided the structural consequences of the resulting changes in pressure are considered;
-   the following dimensional limitations apply:
hb/dc < 10
hb < l00 m
dc < 60 m
-   the transition lies in a single horizontal plane (see Figure 1.1a);
-   the silo does not contain an internal structure such as a cone or pyramid with its apex uppermost, cross-beams, etc. However, a rectangular silo may contain internal ties.
(4)   The following limitations on the stored solids apply to the design rules for silos:
-   each silo is designed for a defined range of particulate solids properties;
-   the stored solid is free-flowing, or the stored solid can be guaranteed to flow freely within the silo container as designed (see 1.5.12 and Annex C);
-   the maximum particle diameter of the stored solid is not greater than 0,03dc (see Figure 1.1d).
NOTE:   When particles are large compared to the silo wall thickness, account should be taken of the effects of single particles applying local forces on the wall.

Eurocode 1: Einwirkungen auf Tragwerke - Teil 4: Einwirkungen auf Silos und Flüssigkeitsbehälter

1.1   Anwendungsbereich
1.1.1   Anwendungsbereich von EN 1991 - Eurocode 1
(1)P Die Reihe EN 1991 macht Angaben zu allgemeinen Prinzipien und zu Einwirkungen für die Bemessung von Bauten und Ingenieurbauwerken, einschließlich einer Reihe von geotechnischen Fragen. Die Norm ist in Verbindung mit EN 1990 sowie den Normen der Reihen EN 1992 bis EN 1999 anzuwenden.
(2)   Die Reihe EN 1991 deckt darüber hinaus Einwirkungen während der Bauausführung und Einwirkungen auf Bauwerke mit begrenzter Standzeit ab. Die Reihe bezieht sich auf alle Umstände unter denen das Tragwerk ein angemessenes Verhalten erfordert.
(3)   Die Reihe EN 1991 ist nicht unmittelbar für die Anwendung auf bereits ausgeführte Konstruktion bzw. die Bemessung bei Instandsetzung und Tragwerksänderung und die Beurteilung bei Nutzungsänderung vorgesehen.
(4)   Die Reihe EN 1991 deckt nicht vollständig besondere Bemessungssituationen ab, die außergewöhnliche Zuverlässigkeitsbetrachtungen erfordern, wie z. B. für Tragwerke aus dem Kerntechnikbereich, bei denen besondere Überlegungen bei der Bemessung angestellt werden müssen.
1.1.2   Anwendungsbereich von EN 1991-4 - Einwirkungen auf Silos und Flüssigkeitsbehälter
(1)P Diese Norm enthält allgemeine Prinzipien und Angaben zu den Einwirkungen für den Entwurf und die Bemessung von Silos für die Lagerung von Schüttgütern und von Flüssigkeitsbehältern. Sie ist in Verbindung mit EN 1990, mit den anderen Teilen der Reihe EN 1991 sowie mit den Normen der Reihen EN  1992 bis EN 1999 anzuwenden.
(2)   Diese Norm enthält auch einige Bestimmungen für Einwirkungen auf Silos und Flüssigkeitsbehälter, die über die unmittelbaren Einwirkungen infolge von den gelagerten Schüttgütern oder Flüssigkeiten hinausgehen (z. B. Auswirkungen von Temperaturunterschieden).
(3)   Für die Anwendung der Bemessungsregeln für Silozellen und Silobauwerke gelten folgende geometrische Einschränkungen:

Eurocode 1 - Actions sur les structures - Partie 4: Silos et réservoirs

(1)P   La présente partie donne les principes généraux et les actions pour la conception de la structure des silos (pour le stockage de particules solides) et des réservoirs (pour le stockage des liquides), et doit etre utilisé conjointement avec l'EN 1990, avec d'autres parties de l'EN 1991, et avec les EN 1992 a 1999.
(2)   Cette partie contient aussi certaines indications sur les actions sur les structures des silos et réservoirs qui ne sont pas liées aux solides ou aux liquides contenus (par exemple les effets thermiques différentiels, ou les tassements différentiels dans les batteries de silos).
(3)   Les regles de dimensionnement données pour les silos sont valables avec les limitations géométriques suivantes :
-   les formes de section des silos sont limitées a celles qui sont montrées a la Figure 1.1d, cependant des petites variations pourront etre acceptées a condition que les conséquences structurelles des changements résultants de contrainte soient prises en compte ;
-   les limitations dimensionnelles sont les suivantes :
-   hb/dc  10
-   hb  <  l00 m
-   dc  60 m
-   la transition est dans un plan horizontal unique (voir la Figure 1.1a) ;
-   le silo ne contient pas de structure interne telle qu'un cône ou une pyramide avec pointe vers le haut, des poutres transversales etc. Toutefois, s'il s'agit d'un silo rectangulaire, il peut etre muni de tirants internes.
(4)   Les regles de dimensionnement données pour les silos sont valables avec les limitations suivantes concernant les solides ensilés :
-   chaque silo est conçu pour un domaine défini quant aux propriétés des solides particulaires a stocker ;
-   le matériau ensilé est a écoulement libre, ou il peut etre garanti qu'il pourra couler librement a l'intérieur du silo considéré (voir 1.5.12 et l'Annexe C) ;
-   le diametre maximal des grains de matiere ensilée ne dépasse pas 0,03dc (voir la Figure 1.1d).

Evrokod 1: Vplivi na konstrukcije – 4. del: Silosi in rezervoarji

General Information

Status
Published
Publication Date
31-Oct-2006
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
01-Nov-2006
Due Date
01-Nov-2006
Completion Date
01-Nov-2006

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2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Eurocode 1 - Actions on structures - Part 4: Silos and tanksEvrokod 1: Vplivi na konstrukcije – 4. del: Silosi in rezervoarjiEurocode 1 - Actions sur les structures - Partie 4: Silos et réservoirsEurocode 1: Einwirkungen auf Tragwerke - Teil 4: Einwirkungen auf Silos und FlüssigkeitsbehälterTa slovenski standard je istoveten z:EN 1991-4:2006SIST EN 1991-4:2006en91.010.30Technical aspectsICS:SIST ENV 1991-4:20041DGRPHãþDSLOVENSKI
STANDARDSIST EN 1991-4:200601-november-2006







EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 1991-4May 2006ICS 91.010.30Supersedes ENV 1991-4:1995
English VersionEurocode 1 - Actions on structures - Part 4: Silos and tanksEurocode 1 - Actions sur les structures - Partie 4: Silos etréservoirsEurocode 1 - Grundlagen der Tragwerksplanung undEinwirkungen auf Tragwerke - Teil 4: Silos undFlüssigkeitsbehälterThis European Standard was approved by CEN on 12 October 2005.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 Central Secretariat 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 Central Secretariat has the same status as the officialversions.CEN members are the national standards bodies of Austria, Belgium, 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© 2006 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 1991-4:2006: E



EN 1991-4:2006 (E) 2 CONTENTS
Page FOREWORD 5 BACKGROUND OF THE EUROCODE PROGRAMME.5 STATUS AND FIELD OF APPLICATION OF EUROCODES.6 NATIONAL STANDARDS IMPLEMENTING EUROCODES.6 LINKS BETWEEN EUROCODES AND HARMONIZED TECHNICAL SPECIFICATIONS (ENS AND ETAS) FOR PRODUCTS.7 ADDITIONAL INFORMATION SPECIFIC TO EN1991-4.7 NATIONAL ANNEX FOR EN1991-4.7 SECTION 1
GENERAL 8 1.1 SCOPE.8 1.1.1 Scope of EN 1991 - Eurocode 1.8 1.1.2 Scope of EN 1991-4 actions on structures: silos and tanks.8 1.2 NORMATIVE REFERENCES.10 1.3 ASSUMPTIONS.11 1.4 DISTINCTION BETWEEN PRINCIPLES AND APPLICATION RULES.11 1.5 DEFINITIONS.11 1.6 SYMBOLS USED IN PART 4 OF EUROCODE 1.15 1.6.1 Roman upper case letters.15 1.6.2 Roman lower case letters.16 1.6.3 Greek upper case letters.19 1.6.4 Greek lower case letters.20 1.6.5 Subscripts.21 SECTION 2
REPRESENTATION AND CLASSIFICATION OF ACTIONS 22 2.1 REPRESENTATION OF ACTIONS ON SILOS.22 2.2 REPRESENTATION OF ACTIONS ON TANKS.23 2.3 CLASSIFICATION OF ACTIONS ON SILOS.23 2.4 CLASSIFICATION OF ACTIONS ON TANKS.23 2.5 ACTION ASSESSMENT CLASSIFICATION.23 SECTION 3
DESIGN SITUATIONS 25 3.1 GENERAL.25 3.2 DESIGN SITUATIONS FOR STORED SOLIDS IN SILOS.25 3.3 DESIGN SITUATIONS FOR DIFFERENT SILO GEOMETRICAL ARRANGEMENTS.26 3.4 DESIGN SITUATIONS FOR SPECIFIC CONSTRUCTION FORMS.31 3.5 DESIGN SITUATIONS FOR STORED LIQUIDS IN TANKS.32 3.6 PRINCIPLES FOR DESIGN FOR EXPLOSIONS.32 SECTION 4
PROPERTIES OF PARTICULATE SOLIDS 33 4.1 GENERAL.33 4.2 PARTICULATE SOLIDS PROPERTIES.34 4.2.1 General.34 4.2.2 Testing and evaluation of solids properties.35 4.2.3 Simplified approach.36 4.3 TESTING PARTICULATE SOLIDS.36 4.3.1 Test procedures.36 4.3.2 Bulk unit weight g.37 4.3.3 Coefficient of wall friction m.37 4.3.4 Angle of internal friction fi.37 4.3.5 Lateral pressure ratio K.37 4.3.6 Cohesion c.38 4.3.7 Patch load solid reference factor Cop.38 SECTION 5
LOADS ON THE VERTICAL WALLS OF SILOS 40 5.1 GENERAL.40 5.2 SLENDER SILOS.40



EN 1991-4:2006 (E) 3 5.2.1 Filling loads on vertical walls.40 5.2.2 Discharge loads on vertical walls.45 5.2.3 Substitute uniform pressure increase for filling and discharge patch loads.50 5.2.4 Discharge loads for circular silos with large outlet eccentricities.51 5.3 SQUAT AND INTERMEDIATE SLENDERNESS SILOS.56 5.3.1 Filling loads on vertical walls.56 5.3.2 Discharge loads on vertical walls.58 5.3.3 Large eccentricity filling loads in squat and intermediate circular silos.60 5.3.4 Large eccentricity discharge loads in squat and intermediate circular silos.61 5.4 RETAINING SILOS.61 5.4.1 Filling loads on vertical walls.61 5.4.2 Discharge loads on vertical walls.62 5.5 SILOS CONTAINING SOLIDS WITH ENTRAINED AIR.63 5.5.1 General.63 5.5.2 Loads in silos containing fluidized solids.63 5.6 THERMAL DIFFERENTIALS BETWEEN STORED SOLIDS AND THE SILO STRUCTURE.63 5.6.1 General.63 5.6.2 Pressures due to reduction in ambient atmospheric temperature.64 5.6.3 Pressures due to filling with hot solids.65 5.7 LOADS IN RECTANGULAR SILOS.65 5.7.1 Rectangular silos.65 5.7.2 Silos with internal ties.65 SECTION 6
LOADS ON SILO HOPPERS AND SILO BOTTOMS 66 6.1 GENERAL.66 6.1.1 Physical properties.66 6.1.2 General rules.67 6.2 FLAT BOTTOMS.69 6.2.1 Vertical pressures on flat bottoms in slender silos.69 6.2.2 Vertical pressures on flat bottoms in squat and intermediate silos.69 6.3 STEEP HOPPERS.70 6.3.1 Mobilized friction.70 6.3.2 Filling loads.71 6.3.3 Discharge loads.71 6.4 SHALLOW HOPPERS.72 6.4.1 Mobilized friction.72 6.4.2 Filling loads.73 6.4.3 Discharge loads.73 6.5 HOPPERS IN SILOS CONTAINING SOLIDS WITH ENTRAINED AIR.73 SECTION 7
LOADS ON TANKS FROM LIQUIDS 74 7.1 GENERAL.74 7.2 LOADS DUE TO STORED LIQUIDS.74 7.3 LIQUID PROPERTIES.74 7.4 SUCTION DUE TO INADEQUATE VENTING.74 ANNEX A 75 BASIS OF DESIGN - SUPPLEMENTARY PARAGRAPHS TO EN 1990 FOR SILOS AND TANKS.75 A.1 General.75 A.2 Ultimate limit state.75 A.3 Actions for combination.75 A.4 Design situations and action combinations for Action Assessment Classes 2 and 3.76 A.5 Action combinations for Action Assessment Class 1.78 ANNEX B 79 ACTIONS, PARTIAL FACTORS AND COMBINATIONS OF ACTIONS ON TANKS.79 B.1 General.79 B.2 Actions.79 B.3 Partial factors for actions.81 B.4 Combination of actions.81



EN 1991-4:2006 (E) 4 ANNEX C 82 MEASUREMENT OF PROPERTIES OF SOLIDS FOR SILO LOAD EVALUATION.82 C.1 Object.82 C.2 Field of application.82 C.3 Notation.82 C.4 Definitions.83 C.5 Sampling and preparation of samples.83 C.6 Bulk unit weight g.84 C.7
Wall friction.85 C.8 Lateral pressure ratio K.87 C.9 Strength parameters: cohesion c and internal friction angle fi.88 C.10
Effective elastic modulus Es.91 C.11 Assessment of the upper and lower characteristic values of a property and determination of the conversion factor a.94 ANNEX D 97 EVALUATION OF PROPERTIES OF SOLIDS FOR SILO LOAD EVALUATION.97 D.1 Object.97 D.2 Evaluation of the wall friction coefficient for a corrugated wall.97 D.3 Internal and wall friction for coarse-grained solids without fines.98 ANNEX E 99 VALUES OF THE PROPERTIES OF PARTICULATE SOLIDS.99 E.1 General.99 E.2 Defined values.99 ANNEX F 100 FLOW PATTERN DETERMINATION.100 F.1 Mass and funnel flow.100 ANNEX G 101 ALTERNATIVE RULES FOR PRESSURES IN HOPPERS.101 G.1 General.101 G.2 Notation.101 G.3 Definitions.101 G.4 Design situations.101 G.5 Evaluation of the bottom load multiplier Cb.101 G.6
Filling pressures on flat and nearly-flat bottoms.102 G.7
Filling pressures in hoppers.102 G.8
Discharge pressures on flat or nearly-flat bottoms.103 G.9
Discharge pressures on hoppers.103 G.10
Alternative expression for the discharge hopper pressure ratio Fe.103 ANNEX H 105 ACTIONS DUE TO DUST EXPLOSIONS.105 H.1
General.105 H.2
Scope.105 H.3
Notation.105 H.4
Explosive dusts and relevant properties.105 H.5
Ignition sources.105 H.6
Protecting precautions.106 H.7
Design of structural elements.106 H.8
Design pressure.106 H.9
Design for underpressure.106 H.10 Design of venting devices.107 H.11 Reaction forces by venting.107



EN 1991-4:2006 (E) 5 Foreword This document (EN 1991-4:2006) has been prepared by Technical Committee CEN/TC250 “Structural Eurocode”, the secretariat of which is held by BSI.
This document shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by November 2006, and conflicting national standards shall be withdrawn at the latest by March 2010. This document supersedes ENV 1991-4:1995. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and the 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 harmonization of technical specifications. Within this action programme, the Commission took the initiative to establish a set of harmonized 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 1980s.
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: Basis of structural design EN1991 Eurocode 1: Actions on structures EN1992 Eurocode 2: Design of concrete structures 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
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).



EN 1991-4:2006 (E) 6
urocode standards recognize 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 recognize 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 harmonized 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 harmonized 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. 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:
2) According to Article 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 harmonized ENs and ETAGs/ETAs. 3) According to Article 12 of the CPD the interpretative documents shall: a) give concrete form to the essential requirements by harmonizing 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 harmonized 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.



EN 1991-4:2006 (E) 7 - decisions on the application of informative annexes, - references to non-contradictory complementary information to assist the user to app
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