Or to your national standards organization National Application Documents NADs

13) In view of the responsibilities of authorities in member countries for safety, health and other matters covered by the essential requirements of the Construction Products Directive (CPD), certain safety elements in this ENV have been assigned indicative values which are identified by ("boxed values"). The authorities in each member country are expected to review the "boxed values" and may substitute alternative definitive values for these safety elements for use in national application.

14) Some of the supporting European or International standards may not be available by the time this Prestandard is issued. It is therefore anticipated that a National Application Document (NAD) giving an substitute definitive values for safety elements, referencing compatible supporting standards and providing guidance on the national application of this Prestandard, will be issued by each member country or its Standards Organization.

15) It is intended that this Prestandard is used in conjunction with the NAD valid in the country where the building or civil engineering works is located.

16) The scope of ENV 1991 is defined in clause 1.1.1 and the scope of this part of ENV 1991 is defined in 1.1.2. Additional parts of ENV 1991 which are planned are indicated in 1.1.3.

17) This Part is complemented by a number of informative annexes.

Contents

Foreword

Objectives of the Eurocodes Background to the Eurocode programme Eurocode programme National Application Document (NAD) Section 1. General

1.1 Scope

1.1.1 Scope of ENV 1991 -Eurocode 1

1.1.2 Scope of ENV 1991-4 Actions on silos and tanks

1.1.3 Further Parts of ENV 1991

1.2 Normative references

1.3 Distinction between principles and application rules

1.4 Definitions

1.5 Notations

Section 2. Classification of actions Section 3. Design situations Section 4. Representation of actions Section 5. Loads on silos due to particulate materials

General Slender silos Filling loads

5.2.1.1 Vertical walled section

5.2.1.2 Flat bottoms

5.2.1.3 Hoppers

5.2.2 Discharge loads

5.2.2.1 Vertical walled section

5.2.2.2 Flat bottom and hopper

5.2.2.3 Simplified method for filling and discharge

Squat silos

Homogenizing silos and silos with a high filling velocity

Section 6. Loads on tanks from liquids

6.1 General

6.2 Liquid properties Section 7. Material properties

7.1 Particulate material properties

7.2 Simplified approach

7.3 Testing particulate materials

7.3.1 Bulk weight density 7

7.3.2 Coefficient of wall friction Mm

16 16

18 19 19 19

22 22

23 23 23 23 23

Page

7.3.3 Horizontal to vertical pressure ratio Ks,m 23

7.4 Maximum load magnifier 24 Annex A Basis of design — supplementary clauses to ENV 1991-1 for silos and tanks 25 Annex B Test methods for particulate material properties 26

Annex C Seismic actions 30

Figure 1.1 — Flow patterns 8

Figure 1.2 — Silo forms showing dimensions and pressure notation 11

Figure 5.1 — Limit between mass flow and funnel flow for conical and wedge-shaped hoppers 15

Figure 5.2 — Side elevation and plan view of the patch load 17

Figure 5.3 — Hopper loads and tensile force at the top of the hopper 18

Figure 5.4 — Wall loads and flat bottom loads in squat silos 21

Figure B1 — Test method for determination of wall friction coefficient 27

Figure B2 — Device for the determination of 7 28 Figure B3 — Test method for determining Ks,m0 29

Figure B4 — Test method for determining the angles of internal friction : and :c and the cohesion c at the preconsolidation level ar 30

Figure C1 — Redistribution of particulate materials at the top of the silo 31

Figure C2 — Seismic action for substructure 32 Figure C3 — Plan view of the additional horizontal pressure due to seismic actions on the vertical walled sections of silos with circular and rectangular cross section shapes 32

Table 7.1 — Particulate material properties 24 Table A1 — Y factors for silo loads and tank loads 25

Table B1 — Recommended tests 29

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