Introduction to the StructuralIntroduction to the StructuralEurocodesEurocodes

Dr Andrew BondDr Andrew BondGeocentrix LtdGeocentrix Ltd

www.geocentrix.co.uk/atticwww.geocentrix.co.uk/attic

Outline of lectureOutline of lecture

�� Part 1Part 1�� What are the Structural Eurocodes?What are the Structural Eurocodes?�� Basis of designBasis of design�� Verification of safetyVerification of safety

�� Part 2Part 2�� Geotechnical designGeotechnical design�� Comparison with traditional methodsComparison with traditional methods�� ConclusionsConclusions

What are the StructuralWhat are the StructuralEurocodes?Eurocodes?

Introduction to the StructuralIntroduction to the StructuralEurocodesEurocodes

Common structural design rulesCommon structural design rules

�� Common structural design rules forCommon structural design rules foreveryday use for the design of...everyday use for the design of...�� whole structureswhole structures�� component productscomponent products�� …of both traditional and innovative nature…of both traditional and innovative nature

�� Extremely unusual forms of construction orExtremely unusual forms of construction ordesign conditions are not specificallydesign conditions are not specificallycoveredcovered

EN 1990 Foreword

Structural Eurocode programmeStructural Eurocode programme

�� Basis of designBasis of design�� Eurocode 1 - Actions on structuresEurocode 1 - Actions on structures�� Eurocode 2 - Design of concrete structuresEurocode 2 - Design of concrete structures�� Eurocode 3 - Design of steel structuresEurocode 3 - Design of steel structures�� Eurocode 4 - Design of composite steel and concrete structuresEurocode 4 - Design of composite steel and concrete structures�� Eurocode 5 - Design of timber structuresEurocode 5 - Design of timber structures�� Eurocode 6 - Design of masonry structuresEurocode 6 - Design of masonry structures�� Eurocode 7 - Geotechnical designEurocode 7 - Geotechnical design�� Eurocode 8 - Design of structures for earthquake resistanceEurocode 8 - Design of structures for earthquake resistance�� Eurocode 9 - Design of aluminium structuresEurocode 9 - Design of aluminium structures

Eurocode 3 Part 5: PilingEurocode 3 Part 5: Piling

1: General1: General2: Basis of design2: Basis of design3: Material properties3: Material properties4: Serviceability limit states4: Serviceability limit states5: Ultimate limit states5: Ultimate limit states6: Anchors,6: Anchors, waling waling, bracing and connections, bracing and connections7: Execution7: Execution8: Design assisted by testing8: Design assisted by testingAnnexes A-GAnnexes A-G

Relevance of Eurocode 3 Part 5Relevance of Eurocode 3 Part 5to steel sheet pilesto steel sheet piles

�� Provides advice on durabilityProvides advice on durability�� Allows for plastic designAllows for plastic design�� Good summary of various ground models:Good summary of various ground models:

�� Limit earth pressuresLimit earth pressures�� Subgrade reactionSubgrade reaction�� Fully numerical (finite element)Fully numerical (finite element)

Eurocode 7: Geotechnical designEurocode 7: Geotechnical design

Part 1: General rulesPart 1: General rulesENV issued 1995ENV issued 1995

Part 2: Design assisted by laboratory testingPart 2: Design assisted by laboratory testingENV issued April 1999ENV issued April 1999

Part 3: Design assisted by field testingPart 3: Design assisted by field testingENV issued July 1999ENV issued July 1999

1: General2: Basis of geotechnical design3: Geotechnical data4: Supervision of construction,

monitoring, and maintenance5: Fill, dewatering, ground improvement,

and reinforcement6: Spread foundations7: Pile foundations8: Retaining structures9: EmbankmentsAnnexes

ENV1997-1:1995ENV1997-1:1995

It’s English, Jim, but not as weIt’s English, Jim, but not as weknow itknow it

A.N. BealA.N. BealThomason PartnershipThomason Partnership

A. FundamentalsB. Important features of Eurocode

7 Part 1C. Clause-by-clause commentaryD. The way aheadE. Worked examples

Written by Dr Brian Simpson(Arup Geotechnics) & RichardDriscoll (BRE)

Eurocode 7 - a commentaryEurocode 7 - a commentary

1: Introduction2: Basis of geotechnical design3: Geotechnical investigations and

geotechnical data4: Supervision of construction,

monitoring, and maintenance5: Fill, dewatering, ground improvement,

and reinforcement6: Spread foundations7: Pile foundations8: Retaining structures9: Embankments and slopes

Written by Drs Trevor Orr and EricFarrell (Trinity College, Dublin)

Geotechnical design to Eurocode 7Geotechnical design to Eurocode 7

1: General2: Basis of geotechnical design3: Geotechnical data4: Supervision of construction,

monitoring, and maintenance5: Fill, dewatering, ground improvement,

and reinforcement6: Spread foundations7: Pile foundations8: Anchorages9: Retaining structures10: Hydraulic failure11: Overall stability12: EmbankmentsAnnexes

prEN1990-1:200xprEN1990-1:200x

Authority for European standardsAuthority for European standards

�� European CommissionEuropean Commission�� Council Directive 89/106/EEC on construction projectsCouncil Directive 89/106/EEC on construction projects�� Council Directives 71/305/EEC & 89/440/EEC on Council Directives 71/305/EEC & 89/440/EEC on

public workspublic works

�� European Free Trade AssociationEuropean Free Trade Association�� European Committee forEuropean Committee for Standardization Standardization (CEN) (CEN)

�� Technical Committee CEN/TC250 Technical Committee CEN/TC250 Structural EurocodesStructural Eurocodes�� Standing Committee SC7 Standing Committee SC7 Geotechnical designGeotechnical design

EN 1990 Foreword

Legal status of the EurocodesLegal status of the Eurocodes

�� The Structural Eurocodes shall be given theThe Structural Eurocodes shall be given thestatus of a national standard…status of a national standard…�� either by publication of an identical texteither by publication of an identical text�� or by endorsementor by endorsement

�� Conflicting national standards shall beConflicting national standards shall bewithdrawnwithdrawn

EN 1990 Foreword

Timetable for adoption of Part 1Timetable for adoption of Part 1

�� Experimental ENV periodExperimental ENV period�� November 1994-November 1996November 1994-November 1996

�� Conversion of ENV to ENConversion of ENV to EN�� September 1997-June 2000 (6 months behind)September 1997-June 2000 (6 months behind)

�� Preparation of final draft of ENPreparation of final draft of EN�� July 2000-October 2000July 2000-October 2000

�� Translation/publication in 3 languagesTranslation/publication in 3 languages�� October 2000-January 2002October 2000-January 2002

CEN/TC250/SC7/N311 (18 August 1999)

Timetable for Parts 2 & 3Timetable for Parts 2 & 3

�� ENVsENVs published April/July 1999 published April/July 1999�� Results of enquiries October 2001Results of enquiries October 2001�� Final publication October 2004?Final publication October 2004?

Basis of designBasis of design

Introduction to the StructuralIntroduction to the StructuralEurocodesEurocodes

Key features of EN 1990Key features of EN 1990

�� EN 1990 describes the principles andEN 1990 describes the principles andrequirements for safety, serviceability, andrequirements for safety, serviceability, anddurability of structuresdurability of structures

�� EN 1990 is based on:EN 1990 is based on:�� the limit state conceptthe limit state concept�� in conjunction with a partial factor methodin conjunction with a partial factor method

EN 1990 Foreword

Scope of EN 1990Scope of EN 1990

�� EN 1990:EN 1990:�� establishes principles and requirements for the safety andestablishes principles and requirements for the safety and

serviceability of structuresserviceability of structures�� describes the basis for their design and verificationdescribes the basis for their design and verification�� gives guidelines for related aspects of structural reliabilitygives guidelines for related aspects of structural reliability

�� EN 1990 is EN 1990 is notnot intended for: intended for:�� the structural appraisal of existing constructionthe structural appraisal of existing construction�� developing the design of repairs and alterationsdeveloping the design of repairs and alterations�� assessing changes of useassessing changes of use

EN 1990 §1.1

Principles & application rules - 1Principles & application rules - 1

PrinciplesPrinciples�� General statements and definitions for which thereGeneral statements and definitions for which there

is no alternativeis no alternative�� Requirements and analytical models for which noRequirements and analytical models for which no

alternative is permitted alternative is permitted unless specifically statedunless specifically stated�� Principles are identified by the letter P followingPrinciples are identified by the letter P following

the paragraph numberthe paragraph number

EN 1990 §1.4

Principles & application rules - 2Principles & application rules - 2

Application rulesApplication rules�� Generally recognized rules which follow theGenerally recognized rules which follow the

principles and satisfy their requirementsprinciples and satisfy their requirements�� It is permissible to use alternative design rulesIt is permissible to use alternative design rules

from those given in EN 1990, provided they:from those given in EN 1990, provided they:�� accord with the relevant principlesaccord with the relevant principles�� achieve at least equivalent resistance,achieve at least equivalent resistance,

serviceability, and durability as the Eurocodesserviceability, and durability as the Eurocodes

EN 1990 §1.4

Fundamental requirementsFundamental requirements

�� (P) A structure shall be designed and executed(P) A structure shall be designed and executedin such a way that it will:in such a way that it will:�� remain fit for the use for which it is requiredremain fit for the use for which it is required�� sustain all actions and influences likely to occursustain all actions and influences likely to occur

during execution and useduring execution and use

EN 1990 §2.1

Breakage of embedded wallsBreakage of embedded walls

Limit state designLimit state design

�� (P) A distinction shall be made between:(P) A distinction shall be made between:�� ultimate limit statesultimate limit states�� serviceability limit statesserviceability limit states

�� Verification of one limit state may be omittedVerification of one limit state may be omittedif its requirements are met by the otherif its requirements are met by the other

�� Limit states should be related to designLimit states should be related to designsituationssituations

EN 1990 §3.1

Design situationsDesign situations

�� ((P) Design situations shall be classified as:P) Design situations shall be classified as:�� persistent (i.e. conditions of normal use)persistent (i.e. conditions of normal use)�� transient (i.e. temporary conditions, e.g. duringtransient (i.e. temporary conditions, e.g. during

execution or repair)execution or repair)�� accidental (i.e. exceptional conditions, e.g.accidental (i.e. exceptional conditions, e.g.

exposure to fire, explosion, impact, orexposure to fire, explosion, impact, or localized localizedfailure)failure)

�� seismicseismic

EN 1990 §3.5

Verification of safetyVerification of safety

Introduction to the StructuralIntroduction to the StructuralEurocodesEurocodes

Verification by the partial factorVerification by the partial factormethod: ultimate limit statesmethod: ultimate limit states�� (P) When designing construction works, the(P) When designing construction works, the

following limit states shall be verified:following limit states shall be verified:�� EQU - loss of static equilibrium, EQU - loss of static equilibrium, in which the strength ofin which the strength of

construction materials or ground are not governingconstruction materials or ground are not governing�� STR - internal failure of the structure or structuralSTR - internal failure of the structure or structural

elements, elements, in which the strength of construction materials orin which the strength of construction materials orexcessive deformation of the structure governsexcessive deformation of the structure governs

�� GEO - failure or excessive deformation of the ground, GEO - failure or excessive deformation of the ground, ininwhich the strengths of soil or rock are significantwhich the strengths of soil or rock are significant

�� FAT - fatigue failure of the structure or structural elementsFAT - fatigue failure of the structure or structural elementsEN 1990 §6.4.1

Verification of limit state EQUVerification of limit state EQU

�� (P) When considering a limit state of static(P) When considering a limit state of staticequilibrium (EQU), it shall be verified that:equilibrium (EQU), it shall be verified that:

�� EEd,dstd,dst ≤≤ E Ed,stbd,stb�� EEd,dstd,dst = design value of the effects of destabilizing = design value of the effects of destabilizing

actionsactions�� EEd,stbd,stb = design value of the effects of stabilizing = design value of the effects of stabilizing

actionsactions

EN 1990 §6.4.2

Verification of limit statesVerification of limit statesSTR/GEOSTR/GEO�� (P) When considering a limit state of rupture(P) When considering a limit state of rupture

or excessive deformation (STR and/or GEO), itor excessive deformation (STR and/or GEO), itshall be verified that:shall be verified that:

�� EEdd ≤≤ R Rdd�� EEdd = design value of the effects of actions = design value of the effects of actions�� RRdd = design value of the corresponding resistance = design value of the corresponding resistance

EN 1990 §6.4.2

Verification by the partial factorVerification by the partial factormethod: serviceability limit statesmethod: serviceability limit states�� (P) It shall be verified that:(P) It shall be verified that:�� EEdd ≤≤ C Cdd

�� EEdd = design value of the effects of actions specified = design value of the effects of actions specifiedin the performance criteriain the performance criteria

�� CCdd = limiting design value of E = limiting design value of Edd

�� Partial factors Partial factors γγGG and and γγQQ = 1.0 = 1.0�� Partial factors Partial factors γγMM = 1.0 = 1.0

EN 1990 §6.5.1, 6.54, & 6.5.5

Actions and environmentalActions and environmentalinfluencesinfluences�� Permanent actions (G)Permanent actions (G)

�� likely to act throughout design situationlikely to act throughout design situation�� e.g. self-weight; shrinkage or uneven settlemente.g. self-weight; shrinkage or uneven settlement

�� Variable actions (Q)Variable actions (Q)�� unlikely to act throughout design situationunlikely to act throughout design situation�� variation is neither negligible nor monotonicvariation is neither negligible nor monotonic�� e.g. imposed loads on buildings; wind or snow loadse.g. imposed loads on buildings; wind or snow loads

�� Accidental actions (A)Accidental actions (A)�� short durationshort duration�� e.g. explosions; vehicle impactse.g. explosions; vehicle impacts

EN 1990 §1.5.3 & 4.1.1

Material propertiesMaterial properties

�� Properties of materials (including soil andProperties of materials (including soil androck) are represented by characteristic valuesrock) are represented by characteristic values((XXkk))

�� Unless otherwise stated inUnless otherwise stated in ENs ENs 1991 to 1999: 1991 to 1999:�� where a low value is unfavourable,where a low value is unfavourable, X Xkk = 5% = 5% fractile fractile�� where a high value is unfavourable,where a high value is unfavourable, X Xkk = 95% = 95% fractile fractile

�� Where insufficient statistical data are available,Where insufficient statistical data are available,nominal values may be defined as characteristicnominal values may be defined as characteristic

EN 1990 §4.2

Ground propertiesGround properties

�� (P) Values of ground properties shall be(P) Values of ground properties shall beobtained from test results either directly orobtained from test results either directly orthrough correlation, theory, or empiricismthrough correlation, theory, or empiricism

�� (P) The characteristic value of a soil or rock(P) The characteristic value of a soil or rockparameter shall be selected as a cautiousparameter shall be selected as a cautiousestimate of the value affecting the occurrenceestimate of the value affecting the occurrenceof the limit stateof the limit state

EN 1997-1 §2.4.4.2

From lab. & field to design...From lab. & field to design...

Design value

Characteristic value

Values of ground properties

Laboratory and field test results

Partial factors

Theory/correlation/empiricism

Cautiousestimate

Geometrical dataGeometrical data

�� (P) Geometrical data shall be represented by(P) Geometrical data shall be represented bytheir characteristic values or, in some casestheir characteristic values or, in some cases(e.g. in the case of imperfections), directly by(e.g. in the case of imperfections), directly bytheir design valuestheir design values

�� The characteristic values usually correspond toThe characteristic values usually correspond todimensions specified in the designdimensions specified in the design

EN 1990 §4.3

Unplanned excavationUnplanned excavation

hhnomnom

∆∆hh = 10% of h = 10% of hnomnom

BS 8002BS 8002∆∆hh = = min.min. 0.5m 0.5m

Eurocode 7Eurocode 7∆∆hh = = max.max. 0.5m 0.5m

Outline of lectureOutline of lecture

✔✔ Part 1Part 1✔✔ What are the Structural Eurocodes?What are the Structural Eurocodes?✔✔ Basis of designBasis of design✔✔ Verification of safetyVerification of safety

�� Part 2Part 2�� Geotechnical designGeotechnical design�� Comparison with traditional methodsComparison with traditional methods�� ConclusionsConclusions

Introduction to the StructuralIntroduction to the StructuralEurocodesEurocodes

Dr Andrew BondDr Andrew BondGeocentrix LtdGeocentrix Ltd

www.geocentrix.co.www.geocentrix.co.ukuk