Eurocode 2: Design of concrete structures Part 4: Liquid retaining and containing structures

This Draft for Development was prepared by Subcommittee B5252 and is the official English language version of ENV 19924:1998 Eurocode 2: Design of concrete structures Ð Part 4: Liquid retaining and containment structures, as published by the European Committee for Standardization (CEN). This Draft for Development also includes the United Kingdom (UK) National Application Document (NAD) to be used with the ENV in the design of structures to be constructed in the UK. ENV 19924:1998 results from a programme of work sponsored by the European commission to make available a common set of rules for the structural and geotechnical design of building and civil engineering works. This publication should not be regarded as a British Standard. An ENV is made available for provisional application, but does not have the status of a European Standard. The aim is to use the experience gained to modify the ENV so that it can be adopted as a European Standard. The publication of this ENV and its National Application Document should be considered to supersede any reference to a British Standard in previous DD ENV Eurocodes concerning the subject covered by these documents. The values for certain parameters in the ENV Eurocodes may be set by individual CEN Members so as to meet the requirements of national regulations. These parameters are designated by _ in the ENV. During the ENV period of validity, reference should be made to supporting documents listed in the National Application Document (NAD). The purpose of the NAD is to provide essential information, particularly in relation to safety, to enable the ENV to be used for structures constructed in the UK and the NAD takes precedence over the corresponding provisions in the ENV. The Building Regulations 1991, Approved Document A 1992, draws attention to the potential use of ENV Eurocodes as an alternative approach to Building Regulation compliance. ENV 19924:1998 is considered to offer such an alternative approach, when used in conjunction with its NAD. Users of this document are invited to comment on its technical content, ease of use and any ambiguities or anomalies. These comments will be taken into account when preparing the UK national response to CEN on the question of whether the ENV can be converted to an EN. Comments should be sent in writing to the Secretary of Subcommittee B5252, BSI, 389 Chiswick High Road, London, W4 4AL, quoting the document reference, the relevant clause and, where possible, a proposed revision, by 1st March 2001.

This Draft for Development,

having been prepared under the

direction of the Building and Civil

Engineering Sector Committee,

was published under the

authority of the Standards

Committee and comes into effect

on 15 August 2000

 BSI 08-2000

The following BSI references

relate to the work on this

standard:

Committee reference B/525/2

ISBN 0 580 33211 X

DD ENV 1992-4:2000

Amendments issued since publication

Committees responsible for this British Standard

The preparation of this British Standard was entrusted to Technical CommitteeB/525/2, Sturctural use of concrete, upon which the following bodies wererepresented:

Association of Consulting EngineersBritish Cement Association

British Precast Concrete Federation Ltd

Concrete SocietyInstitution of Civil EngineersInstitution of Structural Engineers

ii  BSI 08 2000

DD ENV 1992-4:2000

National foreword

This Draft for Development was prepared by Subcommittee B/525/2 and is the official

English language version of ENV 1992-4:1998 Eurocode 2: Design of concrete structures Ð Part 4: Liquid retaining and containment structures, as published by

the European Committee for Standardization (CEN) This Draft for Development alsoincludes the United Kingdom (UK) National Application Document (NAD) to be usedwith the ENV in the design of structures to be constructed in the UK

ENV 1992-4:1998 results from a programme of work sponsored by the Europeancommission to make available a common set of rules for the structural andgeotechnical design of building and civil engineering works

This publication should not be regarded as a British Standard.

An ENV is made available for provisional application, but does not have the status of aEuropean Standard The aim is to use the experience gained to modify the ENV so that

it can be adopted as a European Standard The publication of this ENV and its NationalApplication Document should be considered to supersede any reference to a BritishStandard in previous DD ENV Eurocodes concerning the subject covered by thesedocuments

The values for certain parameters in the ENV Eurocodes may be set by individual CENMembers so as to meet the requirements of national regulations These parameters aredesignated by_in the ENV

During the ENV period of validity, reference should be made to supporting documentslisted in the National Application Document (NAD)

The purpose of the NAD is to provide essential information, particularly in relation tosafety, to enable the ENV to be used for structures constructed in the UK and the NADtakes precedence over the corresponding provisions in the ENV

The Building Regulations 1991, Approved Document A 1992, draws attention to thepotential use of ENV Eurocodes as an alternative approach to Building Regulationcompliance ENV 1992-4:1998 is considered to offer such an alternative approach, whenused in conjunction with its NAD

Users of this document are invited to comment on its technical content, ease of useand any ambiguities or anomalies These comments will be taken into account whenpreparing the UK national response to CEN on the question of whether the ENV can

be converted to an EN

Comments should be sent in writing to the Secretary of Subcommittee B/525/2,BSI, 389 Chiswick High Road, London, W4 4AL, quoting the document reference, therelevant clause and, where possible, a proposed revision, by 1st March 2001

Summary of pages

This document comprises a front cover, an inside front cover, pages i to vi, the ENVtitle page, pages 2 to 18, an inside back cover and a back cover

 BSI 08 2000 iii

National Application Document

for use in the UK with ENV 1992-4:1998

iv  BSI 08 2000

DD ENV 1992-4:2000

Contents of National Application Document

Published 1991 DD

ENV1992-1-1:1992

2.3.3.1 Table 2.102 ENV 1991-1 Basis of design and

actions onstructures

Published 1994 DD ENV 1991-1:1996

2.3.3.1(109) Eurocode 7

(ENV 1997-1)

Geotechnicaldesign: Generalrules

Published 1994 DD ENV 1997-1:1995

National Application Document

Introduction

This National Application Document (NAD) has been

prepared under the direction of the Building and

Civil Engineering Sector Committee It has been

developed from:

a) a textual examination of ENV 1992-4:1998;

b) a parametric calibration against BS 8110, BS

8007, supporting standards and test data

1 Scope

This NAD provides information to enable ENV

1992-4:1998 (hereafter referred to as EC2: Part 4) to

be used for the design of structures to be

constructed in the UK It will be used in conjunction

with DD ENV 1992-1-1:1992, the NAD of which refers

to BSI publication for values of actions

2 Partial factors, combination factors

and other values

a) The values for combination coefficients (ψ)

given in Table 1 of the NAD for EC2:Part 1.1 are

not appropriate and a value of 1 forψ0,ψ1and ψ2

should be applied to the operating load as given

in 2.2.2.3 (103) of EC2:Part 4.

b) The values for partial factors for normal

temperature design should be those given

in 2.3.3.1 of EC2:Part 4.

3 Reference standards

Supporting standards including materials

specification and standards for construction are

listed in Table 1 of this NAD

4.2 Clause 4 Section and member design

a) Sub-clause 4.4.2.4 (109)

This Sub-clause should be revised as follows:ªFor members subject predominantly to intrinsicimposed deformations (e.g thermal contraction orshrinkage) the minimum mean strain esm,minshould be taken as that given by equation (4.184).For strains less than esm,min crack widths areconstant at spacings generally greater than thatgiven by equation (4.82)

The definition of the symbols is as in 4.4.2.2 of

part 1 There is no necessity to take any furthermeasures to deal with the long term effects.º

4.3 Clause 5 Detailing provisions

blank

European Committee for StandardizationComite EuropeÂen de NormalisationEuropaÈisches Komitee fuÈr Normung

Central Secretariat: rue de Stassart 36, B-1050 Brussels

1998 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN nationalMembers

Ref No ENV 1992-4:1998 E

EUROPEAN STANDARD ENV 1992-4

NORME EUROPE Â ENNE

EUROPA È ISCHE NORM December 1998

ICS 91.010.30; 91.080.40

Descriptors: civil engineering, buildings, concrete structures, design, building codes, compulation

English version

Eurocode 2: Design of concrete structures Ð Part 4: Liquid

retaining and containment structures

Eurocode 2: Calcul des structures en beÂton Ð

Partie 4: Structures de souteÁnement et reÂservoirs

Eurocode 2: Planung von Stahlbeton- undSpannbetontragwerken Ð Teil 4: StuÈtz- undBehaÈlterbauwerke aus Beton

This European Standard was approved by CEN on 27 May 1997 as a prospective

standard for provisional application

The period of validity of the ENV is limited initially to three years After two years

the members of CEN will be requested to submit their comments, particularly on

the question whether the ENV can be converted into a European Standard

CEN members are required to announce the existence of this ENV in the same way

as for an EN and make the ENV available promptly at national level in an

appropriate form It is permissible to keep conflicting national standards in force (in

parallel to the ENV) until the final decision about the possible conversion of the

ENV into an EN is reached

CEN members are the national standards bodies of Austria, Belgium, Czech

Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy,

Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and

United Kingdom

Page 2

ENV 1992-4:1998

 BSI 08-2000

Foreword

Objectives of the Eurocodes

(1) The ªStructural Eurocodesº comprise a group of

standards for the structural and geotechnical design of

buildings and civil engineering works

(2) They cover execution and control only to the

extent that is necessary to indicate the quality of the

construction products, and the standard of the

workmanship needed to comply with the assumptions

of the design rules

(3) Until the necessary set of harmonized technical

specifications for products and for the methods of

testing their performance are available, some of the

Structural Eurocodes cover some of these aspects in

informative Appendices

Background of the Eurocode Programme

(4) The Commission of the European Communities

(CEC) initiated the work of establishing a set of

harmonized technical rules for the design of building

and civil engineering works which would initially serve

as alternatives to the different rules in force in the

various Member States and would ultimately replace

them These technical rules became known as the

ªStructural Eurocodesº

(5) In 1990, after consulting their respective Member

States, the CEC transfe rred the work of further

development, issue and updating of the Structural

Eurocodes to CEN, and the EFTA Secretariat agreed to

support the CEN work

(6) CEN Technical Committee CEN/TC 250 is

responsible for all Structural Eurocodes

Eurocode Programme

(7) Work is in hand on the following Structural

Eurocodes, each generally consisting of a number of

parts:

EN 1991 Eurocode 1, Basis of design and actions

on structures;

EN 1992 Eurocode 2, Design of concrete structures;

EN 1993 Eurocode 3, Design of steel structures;

EN 1994 Eurocode 4, Design of composite steel and

concrete structures;

EN 1995 Eurocode 5, Design of timber structures;

EN 1996 Eurocode 6, Design of masonry structures;

EN 1997 Eurocode 7, Geotechnical design;

EN 1998 Eurocode 8, Design provisions for

earthquake resistance of structures;

EN 1999 Eurocode 9, Design of aluminium alloy

structures.

(8) Separate sub-committees have been formed by

CEN/TC 250 for the various Eurocodes listed above

(9) This Part 4 of Eurocode 2 is being published as a

European Prestandard (ENV) with an initial life of

three years

(10) This Prestandard is intended for experimental

application and for the submission of comments

(11) After approximately two years CEN members will

be invited to submit formal comments to be taken intoaccount in determining future actions

(12) Meanwhile feedback and comments on thisPrestandard should be sent to the Secretariat ofCEN/TC 250/SC 2 at the following address:

Deutsches lnstitut fuÈr Normung e.V (DIN)Burggrafenstrasse 6

D Ð 10787 Berlinphone: (+49) 30 ± 26 01 ± 25 01fax: (+49) 30 ± 26 01 ± 12 31

National Application Documents (NADs)

(13) In view of the responsibilities of authorities inmember countries for safety, health and other matterscovered by the essential requirements of the

Construction Products Directive (CPD), certain safetyelements in this ENV have been assigned indicativevalues which are identified by [ ] (ªboxed valuesº) Theauthorities in each member country are expected toassign definitive values to these safety elements.(14) Some of the supporting European or internationalstandards may not be available by the time thisprestandard is issued it is therefore anticipated that aNational Application Document (NAD) giving definitivevalues for the safety elements, referencing compatiblesupporting standards and providing national guidance

on the application of this prestandard, will be issued

by each member country or its Standards Organisation.(15) It is intended that this Prestandard is used inconjunction with the NAD valid in the country wherethe building or civil engineering works is located

Matters specific to this prestandard

(16) The scope of Eurocode 2 is defined in 1.1.1 of

ENV 1992-1-1 and the scope of this part of Eurocode 2

is defined in 1.1.2 Other additional parts of

Eurocode 2 which are already issued as ENV are

indicated in 1.1.3 of ENV 1992-1-1; these cover

additional technologies or applications, andcomplement and supplement this part

(17) In using this prestandard in practice, particularregard should be paid to the underlying assumptions

and conditions given in 1.3 of ENV 1992-1-1.

(18) The five chapters of this prestandard arecomplemented by three informative appendices Theseappendices have been introduced to provide generalinformation on material and structural behaviourwhich may be used in the absence of informationspecifically related to the actual materials used oractual conditions of service

(19) As indicated in paragraph (14) of this Foreword,reference should be made to National ApplicationDocuments which will give details of compatiblesupporting standards to be used For this part ofEurocode 2, particular attention is drawn to theapproved prestandard ENV 206 (Concrete Ðperformance, production, placing and compliancecriteria)

Page 3 ENV 1992-4:1998

 BSI 08-2000

For ENV 1992-4, the following additional subclauses

apply

(20) This part 4 of Eurocode 2 complements

ENV 1992-1-1 for the particular aspects of liquid

retaining and structures for the containment of

granular solids

(21) The framework and structure of this part 4

correspond to ENV 1992-1-1 However, part 4 contains

Principles and Application Rules which are specific to

liquid retaining and containment structures

(22) Where a particular subclause of ENV 1992-1-1 is

not mentioned in this ENV 1992-4, that subclause of

ENV 1992-1-1 applies as far as deemed appropriate in

each case

Some Principles and Application Rules of ENV 1992-1-1

are modified or replaced in this part, in which case the

modified versions supersede those in ENV 1992-1-1 for

the design of liquid retaining or containment

structures

Where a Principle or Application Rule in ENV 1992-1-1

is modified or replaced, the new number is identified

by the addition of 100 to the original number Where a

new Principle or Application Rule is added, it is

identified by a number which follows the last number

in the appropriate clause in ENV 1992-1-1 with 100

added to it

A subject not covered by ENV 1992-1-1 is introduced in

this part by a new subclause The subclause number

for this follows the most appropriate clause number in

ENV 1992-1-1

(23) The numbering of equations, figures, footnotes

and tables in this part follow the same principles as

the clause numbering as described in (22) above

1.1.1 Scope of Part 4 of Eurocode 2 5

1.7 Special symbols used in Part 1 of

3.1.2.5.4 Coefficient of thermal expansion 8

3.1.2.5.6 Specific heat capacity of concrete 83.1.2.6 Heat evolution and temperature

4.1.7 Surfaces of structures designed to

4.3.2.4.4 Variable strut inclination method 9

4.3.6.2 Design of structural elements 9

Page 4

ENV 1992-4:1998

 BSI 08-2000

Page4.4.2.5 Minimizing cracking due to restrained

5.4.7.5 Corner connections between walls 14

5.4.7.6 Provision of movement joints 14

5.4.9.1 Minimum reinforcement areas 14

Informative Appendix 105 Effect of

temperature on the properties of concrete 16

Informative Appendix 106 Calculation of

strains and stresses in uncracked concrete

sections subjected to restrained imposed

Informative Appendix 107 Calculation of

leakage through cracks in elements retaining

Page 5 ENV 1992-4:1998

 BSI 08-2000

1 Introduction

1.1 Scope

Replacement of clause 1.1.2 in ENV 1992-1-1 by:

1.1.1 Scope of part 4 of Eurocode 2

P(l01) Part 4 of Eurocode 2 covers the design of

structures constructed from plain or lightly reinforced

concrete, reinforced concrete or prestressed concrete

for the containment of liquids or granular solids and

other liquid retaining structures

P(l02) Principles and Application Rules are given in

this part for the design of those elements of structure

which directly support the stored liquids or materials

(i.e the walls of tanks, reservoirs or silos) Other

elements which support these primary elements (for

example, the tower structure which supports the tank

in a water tower) should be designed according to the

provisions of part 1 except that the design actions

arising from the retained material will be calculated

according to the provisions of this part

P(103) This part does not cover:

Ð structures for the storage of materials at very low

temperatures;

Ð structures for the storage of materials at very

high temperatures;

Ð structures for the storage of hazardous materials

the leakage of which could constitute a major health

or safety risk;

Ð the selection and design of liners;

Ð design for resistance to fire This is covered by

part 1-2 of Eurocode 2 or by national provisions;

Ð no-fines concrete and aerated concrete

components, and those made with heavy aggregate

or containing structural steel sections (see Eurocode

4 for composite steel-concrete structures);

Ð pressurised vessels;

Ð floating structures;

Ð structures subjected to significant seismic actions

(design for seismic actions is covered in Eurocode 8)

(104) Storage of materials of very low temperatures

may be assumed where the temperature of the stored

material is 220 8C or less For the storage of liquid

petroleum gas see EN 26502-2

(105) Storage of materials of very high temperatures

may be assumed where the temperature of the stored

material exceeds 200 8C

(106) For the selection and design of liners, reference

should be made to appropriate documents

1.7 Special symbols used in part 1 of

Eurocode 2

Addition after 1.7.4.

1.7.5 Special symbols used in part 4 of

Eurocode 2

1.7.5.1 Latin upper case symbols

Er effective modulus of elasticity of the storedmaterial

Lc the crack length (m)

Q leakage rate in m3/s

Qo operating value of imposed load

Qw imposed load from a retained liquid

Rax factor defining the degree of external axialrestraint provided by elements attached to theelement considered

Rm factor defining the degree of moment restraintprovided by elements attached to the elementconsidered

T1 temperature of material in contact withsurface 1

T2 temperature of material in contact withsurface 2

Tm mean steady state temperature of a wall

1.7.5.2 Latin lower case symbols

fctx tensile-strength, however defined

fckT characteristic compressive strength of theconcrete modified to take account oftemperature

a1 resistance to heat flux at surface 1

a2 resistance to heat flux at surface 2

gw partial safety factor on load due to retainedliquid

Dr pressure difference across the element(N/mm2)

DTss steady state temperature difference

eav average strain in the element

eaz actual strain at level z

eiz imposed intrinsic strain at level z

eTr transitional thermal strain

eTh free thermal strain in the concrete

lc conductivity of concrete

rr density of the stored material in kN/m3

yr Poisson's ratio of stored material

sz vertical stress in stored material in kN/m2

h dynamic viscosity of liquid (kg/ms)

2.2.2.3 Representative values of variable actions

Replacement of this subclause by:

P(l01) The main representative value is the

characteristic value, Qk The representative value

corresponding to the specified quantity of the retained

material which the structure is designed to hold should

more properly be called the ªoperating valueº, Qo, but,

for convenience, the symbol Qk, will be used for this

operating value

(102) In a liquid retaining structure where the

maximum level of the liquid can be clearly defined

and where the effective density of the liquid

(allowing for any suspended solids) will not vary

significantly, a lower safety factor, ,gw, than that in

Table 22 of ENV 1992-1-1 may be used on the

characteristic load due to the retained liquid, Qw

(103) If not stated otherwise, the values ofψ0,ψ1

andψ2applied to the operating load should be taken

as 1.0

2.3 Design requirements

2.3.1 General

Addition after Principle P(4):

(105) The design situations to be considered should

comply with ENV 1991-4, clause 3 For liquid

retaining and containment structures made with

concrete, the following design situations may be

relevant:

Ð operating conditions implying patterns of

discharge and filling;

Ð explosions due to powder;

Ð thermal effects caused, for example, by stored

materials or environmental temperature;

Ð imposed deformations

2.3.2 Ultimate limit states

2.3.2.2 Combinations of actions

Add a note below Table 2.1 in ENV 1992-1-1

NOTE Where gwis used for one of the variable actions, gwQwis

substituted for the corresponding value of gQQk.

Replacement of Application Rules (5) to (8) by:

(105) Appropriate values for the characteristic actions

and appropriate combinations of actions are given in

Eurocode 1 part 4: Actions in silos and tanks

2.3.3 Partial safety factors for ultimate limit

states

2.3.3.1 Partial safety factors for actions on structures

Replacement of Table 2.2 by:

Table Ð 2.102: Partial safety factors for actions in containment structures for persistent and transient situations

permanent actions

variable actions, general

variable actions due to retained liquid

stressing

Favourableeffect

[0.9] or[1.0]Unfavourable

effect

[1.35]* [1.5] [1.2]1) [1.2] or

[1.0]

* See also paragraphs (3) in this clause in part 1 and (109) below.

** See Eurocode 1; in normal circumstances, gQ,inf= 0.

*** See relevant clauses.

1)Covering model uncertainties, see ENV 1991-1, clause 9 and

annex A.

Replacement of Application Rule (8) by:

(108) By adopting the y values given in Table 2.102,the expression [2.7(a)] may be replaced by thefollowing:

Ð for design situations with only one variableaction Qk,1or Qw:

∑gGjGkj+ 1,5 Qk,1or1.2Qw [2.108(a)]

Ð for design situations with two or more variableactions:

∑gGjGkj+ 1.35i $ 1S Qk,i+1.2Qw [2.108(b)]whichever gives the most unfavourable effect.Equations [2.108(a)] and [2.108(b)] should be used

only, if the conditions for the action Qw

in 2.2.2.3 (102) are met Otherwise, the partial safety

factor gQ= 1.5 should be applied to Qw.(109) Actions resulting from soil or water within soilare treated as permanent actions and should beobtained in accordance with Eurocode 7 Actionsfrom retained materials in silos should be considered

as variable actions

(110) It should be noted that, where backfill isplaced against the outside walls of a structure, it isrequired that the safety should be checked both withand without the soil present