Development and basic aspects of EN 1992 and EN...

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Development and basic aspects of EN 1992 and EN 1998

Prof. A.J. KapposDept. of Civil Engineering

Aristotle University of Thessaloniki

Athens, 11 October 2006

Technical Chamber of Greece – Structural Eurocodes meeting

EN 1992 : 2003EN 1992 : 2003Eurocode 2: Design of Eurocode 2: Design of concreteconcrete

structuresstructures

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GENERAL STRUCTURE OF EUROCODE 2GENERAL STRUCTURE OF EUROCODE 2

EN 1992EN 1992--11--11 GENERAL RULES AND RULESGENERAL RULES AND RULESFOR BUILDINGSFOR BUILDINGS

EN 1992EN 1992--11--22 FIRE DESIGNFIRE DESIGN

EN 1992EN 1992--22 DESIGN ON CONCRETEDESIGN ON CONCRETEBRIDGESBRIDGES

EN 1992EN 1992--33 SILOS AND TANKSSILOS AND TANKS

1. General1. General2. Basis of design2. Basis of design

2.1 Requirements2.1 Requirements2.2 Principles of limit state design2.2 Principles of limit state design2.3 Basic variables2.3 Basic variables2.4 Verification by the partial factor method2.4 Verification by the partial factor method2.5 Design assisted by testing2.5 Design assisted by testing2.6 Supplementary requirements for foundations2.6 Supplementary requirements for foundations2.7 Requirements for fastenings2.7 Requirements for fastenings

3. Materials3. Materials3.1 Concrete3.1 Concrete3.2 Reinforcing steel3.2 Reinforcing steel3.3 Prestressing steel3.3 Prestressing steel3.4 Prestressing devices3.4 Prestressing devices

4. Durability and cover to reinforcement4. Durability and cover to reinforcement4.1 General4.1 General4.2 Environmental conditions4.2 Environmental conditions4.3 Requirements for durability4.3 Requirements for durability4.4 Methods of verification4.4 Methods of verification

ContentContent of EN 1992EN 1992--11--11

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5. Structural analysis5. Structural analysis5.1 General5.1 General5.2 Geometric imperfections5.2 Geometric imperfections5.3 Idealisation of the structure5.3 Idealisation of the structure5.4 Linear elastic analysis5.4 Linear elastic analysis5.5 Linear analysis with limited redistribution5.5 Linear analysis with limited redistribution5.6 Plastic analysis5.6 Plastic analysis5.7 Non5.7 Non--linear analysislinear analysis5.8 Second order effects with axial load5.8 Second order effects with axial load5.9 Lateral instability of slender beams5.9 Lateral instability of slender beams5.10 Prestressed members and structures5.10 Prestressed members and structures5.11 Analysis for some particular structural members5.11 Analysis for some particular structural members

6. Ultimate limit states (ULS)6. Ultimate limit states (ULS)6.1 Bending with or without axial force6.1 Bending with or without axial force6.2 Shear6.2 Shear6.3 Torsion6.3 Torsion6.4 Punching6.4 Punching6.5 Design with strut and tie models6.5 Design with strut and tie models

EN 1992EN 1992--11--1 : Content (cont1 : Content (cont’’d)d)

6.6 Anchorages and laps6.6 Anchorages and laps6.7 Partially loaded areas6.7 Partially loaded areas6.8 Fatigue6.8 Fatigue

7. Serviceability limit states (SLS)7. Serviceability limit states (SLS)7.1 General7.1 General7.2 Stress limitation7.2 Stress limitation7.3 Crack control7.3 Crack control7.4 Deflection control7.4 Deflection control

8 Detailing of reinforcement and prestressing tendons 8 Detailing of reinforcement and prestressing tendons -- GeneralGeneral8.1 General8.1 General8.2 Spacing of bars8.2 Spacing of bars8.3 Permissible mandrel diameters for bent bars8.3 Permissible mandrel diameters for bent bars8.4 Anchorage of longitudinal reinforcement8.4 Anchorage of longitudinal reinforcement8.5 Anchorage of links and shear reinforcement8.5 Anchorage of links and shear reinforcement8.6 Anchorage by welded bars8.6 Anchorage by welded bars8.7 Laps and mechanical couplers8.7 Laps and mechanical couplers8.8 Additional rules for large diameter bars8.8 Additional rules for large diameter bars8.9 Bundled bars8.9 Bundled bars8.10 Prestressing tendons8.10 Prestressing tendons


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9. Detailing of members and particular rules9. Detailing of members and particular rules9.1 General9.1 General9.2 Beams9.2 Beams9.3 Solid slabs9.3 Solid slabs9.4 Flat slabs9.4 Flat slabs9.5 Columns9.5 Columns

9.6 Walls9.6 Walls9.7 Deep beams9.7 Deep beams9.8 Foundations9.8 Foundations9.9 Regions with discontinuity in geometry or action9.9 Regions with discontinuity in geometry or action9.10 Tying systems9.10 Tying systems

10. Additional rules for precast concrete elements and structure10. Additional rules for precast concrete elements and structuress10.1 General10.1 General10.2 Basis of design, fundamental requirements10.2 Basis of design, fundamental requirements10.3 Materials10.3 Materials10.5 Structural analysis10.5 Structural analysis10.9 Particular rules for design and detailing10.9 Particular rules for design and detailing


11. Lightweight aggregated concrete structures11. Lightweight aggregated concrete structures11.1 General11.1 General11.2 Basis of design11.2 Basis of design11.3 Materials11.3 Materials11.4 Durability and cover to reinforcement11.4 Durability and cover to reinforcement11.5 Structural analysis11.5 Structural analysis11.6 Ultimate limit states11.6 Ultimate limit states11.7 Serviceability limit states11.7 Serviceability limit states11.8 Detailing of reinforcement 11.8 Detailing of reinforcement -- GeneralGeneral11.9 Detailing of members and particular rules11.9 Detailing of members and particular rules11.10 Additional rules for precast concrete elements and structu11.10 Additional rules for precast concrete elements and structuresres11.12 Plain and lightly reinforced concrete structures11.12 Plain and lightly reinforced concrete structures

12. Plain and lightly reinforced concrete structures12. Plain and lightly reinforced concrete structures12.1 General12.1 General12.2 Basis of design12.2 Basis of design12.3 Materials12.3 Materials12.5 Structural analysis: ultimate Limit states12.5 Structural analysis: ultimate Limit states12.6 Ultimate limit states12.6 Ultimate limit states12.7 Serviceability limit states12.7 Serviceability limit states12.9 Detailing of members and particular rules12.9 Detailing of members and particular rules


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AnnexesAnnexesA (Informative)A (Informative)

Modification of partial factors for materialsModification of partial factors for materialsB (Informative)B (Informative)

Creep and shrinkage strainCreep and shrinkage strainC (Normative)C (Normative)

Reinforcement propertiesReinforcement propertiesD (Informative)D (Informative)

Detailed calculation method for prestressing steel relaxation loDetailed calculation method for prestressing steel relaxation lossesssesE (Informative)E (Informative)

Indicative Strength Classes for durabilityIndicative Strength Classes for durabilityF (Informative)F (Informative)

Reinforcement expressions for inReinforcement expressions for in--plane stress conditionsplane stress conditionsG (Informative)G (Informative)

Soil structure interactionSoil structure interactionH (Informative)H (Informative)

Global second order effects in structuresGlobal second order effects in structuresI (Informative)I (Informative)

Analysis of flat slabs and shear wallsAnalysis of flat slabs and shear wallsJ (Informative)J (Informative)

Examples of regions with discontinuity in geometry or actionExamples of regions with discontinuity in geometry or action


EN 1992EN 1992--11--1: General Overview1: General OverviewComparative studies show that the overall economy of Comparative studies show that the overall economy of construction of designs to EC2 are largely similar to those construction of designs to EC2 are largely similar to those currently designed using actual national design standardscurrently designed using actual national design standardsThere is little practical difference in results of design for There is little practical difference in results of design for bendingbendingThe style of the Eurocodes and the way they are The style of the Eurocodes and the way they are implemented are appreciably different, and there are some implemented are appreciably different, and there are some significant changes in aspects of the design process.significant changes in aspects of the design process.There are associated changes arising through related There are associated changes arising through related Eurocodes and product standards. These make a Eurocodes and product standards. These make a suite of suite of documentsdocuments, including: , including:

–– EN206 EN206 Concrete: Performance, Production, Placing and Concrete: Performance, Production, Placing and Compliance Criteria,Compliance Criteria, and and

–– EN13670 EN13670 Execution of Concrete StructuresExecution of Concrete Structures

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FUNDAMENTALFUNDAMENTAL REQUIREMENTSREQUIREMENTS

•• SAFETY (STRUCTURAL RESISTANCE)SAFETY (STRUCTURAL RESISTANCE)

•• SERVICEABILITYSERVICEABILITY

•• DURABILITYDURABILITY

-- Design Design workingworking lifelife

-- Inspection Inspection andand maintenance maintenance levels levels

•• ECONOMYECONOMY

•• AESTHETICSAESTHETICS

VerificationVerification of of safetysafety andand serviceabiltyserviceabilty by by thethe partial partial factorfactor methodmethod for :for :

ULTIMATE LIMIT STATESULTIMATE LIMIT STATES ULSULSSERVICEABILITY LIMIT STATESSERVICEABILITY LIMIT STATES SLSSLS

BasisBasis of of design design –– partial safety factorspartial safety factors

1,001,00γγF,fatF,fatFatigue Fatigue loadsloads1,201,20γγP,P,unfavunfavUnfavourableUnfavourable local local effectseffects1,301,30γγP,P,unfavunfavULS ULS withwith externalexternal prestressingprestressing1,001,00γγP,P,favfavFavourableFavourable effecteffect

PrestressPrestress

1.001.00γγSHSHShrinkageShrinkage

ValueValueSymbolSymbolCommentCommentActionAction

1.151.15Persistent Persistent andand transienttransient design design situationssituations

1.151.15Persistent Persistent andand transienttransient design design situationssituationsSteelSteel

((reinforcementreinforcement))

1.51.5Persistent Persistent andand transienttransient design design situationssituations

1,001,00γγSS

AccidentalAccidental design situationdesign situation

SteelSteel((prestressingprestressing))

1,001,00γγSS


1.21.2γγCC


ConcreteConcreteValueValueSymbolSymbolCommentCommentMaterialsMaterials

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StructuralStructural AnalysisAnalysis

LinearLinear elasticelastic analysisanalysis (ULS(ULS--SLS)SLS)

LinearLinear analysisanalysis withwith limitedlimited redistribution (ULS)redistribution (ULS)

Plastic Plastic analysisanalysis (ULS)(ULS)

NonNon--linearlinear analysisanalysis (ULS(ULS--SLS)SLS)

DesignDesign value of value of prestressingprestressing forcesforces

PPm,tm,t meanmean value value atat time t.time t.

1, == PtmPd PP γγ

Ultimate Limit States : bending with or without Ultimate Limit States : bending with or without axial forceaxial force

AssumptionsAssumptionsPlane sections remain planePlane sections remain planeTensile strength of concrete ignoredTensile strength of concrete ignoredNo relative slip between concrete and steel No relative slip between concrete and steel Possible strain distributions in crossPossible strain distributions in cross--sectionssections

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Possible strain distributions in the Possible strain distributions in the Ultimate Limit StateUltimate Limit State

dh

As2

Ap

As1

Δεp

udεs ,ε pε εc

0 c2ε(ε ) c3

cu2ε(ε ) cu3

A

B

C

(1- εc2/εcu2)hor

(1- εc3/εcu3)h

εp(0)

εy

A A -- ReinforcingReinforcing steelsteel tension tension strainstrain limitlimitB B -- ConcreteConcrete compression compression strainstrain limitlimitC C -- ConcreteConcrete pure compression pure compression strainstrain limitlimit

UltimateUltimate limitlimit state state –– ShearShear

VVRdRd,c ,c DesignDesign shearshear resistanceresistance of of thethe membermember withoutwithoutshearshear reinforcementreinforcement

VVRd,s Rd,s DesignDesign value of value of thethe shearshear force force whichwhich cancan bebesustainedsustained by by thethe yieldingyielding shearshear reinforcementreinforcement

VVRd,maxRd,max DesignDesign value of value of thethe maximum maximum shearshear force force whichwhichcancan bebe sustainedsustained by by thethe membermember limitedlimited by by crushingcrushing of of thethe compression compression strutsstruts

GeneralGeneral verificationverification procedureprocedure : : VVEd Ed ≤≤ VVRdRd

1)1) VVEd Ed ≤≤ VVRdRd,c ,c

2)2) VVEd Ed ≤≤ VVRdRd,s,s and Vand VEd Ed ≤≤ VVRdRd,max,max

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TrussTruss Model & Notation for Shear Reinforced MembersModel & Notation for Shear Reinforced Members

VVRdRd,c,c = [(0,18/= [(0,18/γγcc))kk(100 (100 ρρllffckck))1/31/3 + 0,15 + 0,15 σσcpcp] ] bbwwdd

kk = 1 + (200/d)= 1 + (200/d)1/21/2

dd effective depth of the crosseffective depth of the cross--section in mmsection in mm

ρρll = = AAssll / / bbww d < 0,02 d < 0,02 AAslsl area of the tensile area of the tensile reinforcement, reinforcement, bbww smallest width of the crosssmallest width of the cross--section in the tensile areasection in the tensile area

σσcp cp = = NNEdEd / A/ Ac c (> 0 compression)(> 0 compression)

Min. value Min. value VVRdRd,c,c = (0, 035k= (0, 035k3/23/2..ffckck1/21/2 + 0,15+ 0,15σσcpcp) ) bbwwdd

UltimateUltimate limitlimit state state –– Shear (contnd)Shear (contnd)

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Inf. ofInf. of VVRdRd,s,s = (= (AAswsw/s) z /s) z ffywdywd cotcotθθ

andand VVRdRd,max ,max = = bbww z z νν ffcdcd/(cot/(cotθθ + tan+ tanθθ ) )

νν = 0,6 [ 1= 0,6 [ 1-- ffckck / 250 ]/ 250 ]

1 < cot 1 < cot θθ < 2,5 or 45< 2,5 or 45°° > > θθ > 22> 22°°In case of a compression axial force : In case of a compression axial force : ααcwcw VVRdRd,max,max

Increased resistance 1Increased resistance 1,25 > α,25 > αc wc w>> 1 1 where where 0 < 0 < σσcmcm< 0,6f< 0,6fcd cd

Reduced resistance Reduced resistance ααcwcw << 1 1 where where σσcmcm> 0,6 > 0,6 ffcd cd

UltimateUltimate limitlimit state state –– Shear (contnd)Shear (contnd)

ShearShear betweenbetween webweb andand flangesflanges of Tof T--sectionssections

ShearShear atat thethe interface interface betweenbetween concreteconcrete castcast atatdifferentdifferent timestimes

1,0 1,0 ≤≤ cotcotθθff ≤≤ 2,02,0(compression (compression flangeflange))

1,0 1,0 ≤≤ cotcotθθff ≤≤ 1,251,25(tension (tension flangeflange))

C C andand µµ are are factorsfactors whichwhich dependdepend on on thethe roughnessroughness of of thethe interfaceinterface

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UltimateUltimate limitlimit state verificationsstate verifications

B C

TEd

tef

A

tef/2

zi

TORSIONTORSIONA A -- CentreCentre--linelineB B -- OuterOuter edgeedge of effective crossof effective cross--section, section, circumferencecircumference uu,,C C -- Cover Cover

2d

θ

A

c

d hθ

θ = arctan (1/2) = 26,6°

C

B D

2d

rcont

PUNCHINGPUNCHINGA A -- Basic control sectionBasic control sectionB B -- Basic control area Basic control area AAcontcontC C -- Basic control Basic control perimeterperimeter uu11D D –– LoadedLoaded area area AAloadload

DesignDesign withwith strutstrut andand tietie modelsmodelsFor zones For zones wherewhere a nona non--linearlinear strainstrain distribution distribution existsexists

VerificationVerification of of strutsstruts ((concreteconcrete))

strutsstruts withoutwithout transverse tensiontransverse tension

strutsstruts withwith transverse tensiontransverse tension((compressedcompressed andand crackedcracked zones)zones)

H

bef

h = H/2z = h/2

bF

a

F

a

F

F

D

D

B

h = b

bef

b

bef = b bef = 0,5H + 0,65a; a ≤ h

VerificationVerification of of tiesties ::

B B –– ContinuityContinuity regionregion

D D –– DiscontinuityDiscontinuityregionregion

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Examples ofExamples of strutstrut andand tietie modelsmodels::•• forfor halfhalf joints joints ((§§ 10 10 –– precastprecast concreteconcrete elements & structures)elements & structures)•• forfor a a corbelcorbel ((AnnexAnnex JJ-- regions with discontinuitiesregions with discontinuities))

ServiceabilityServiceability limit statelimit state

FunctioningFunctioning of of thethe structure in normal usestructure in normal useComfortComfort of peopleof peopleAppearanceAppearance

TheThe verificationverification rulesrules are are deemeddeemed to to ensure:ensure:–– thethe appropriateappropriate serviceabilityserviceability levellevel–– thethe durabilitydurability for for thethe design design workingworking lifelife

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Serviceability criteriaServiceability criteria

EEdd ≤≤ CCd d

TheThe verificationsverifications relate to:relate to:stressstress limitationlimitationlimitationlimitation of crack of crack widthwidthlimitationlimitation of of deformationsdeformationslimitationlimitation of vibrationsof vibrations

Actions Actions andand materialmaterial propertiesproperties are are takentaken intointoaccountaccount withwith theirtheir representativerepresentative values (partial values (partial factorsfactors equalequal to to 1,1, unlessunless otherwiseotherwise specifiedspecified))

EN 1998EN 1998--1 : 20041 : 2004Eurocode 8 : Design of structures

for earthquake resistance

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Contents of EN 1998Contents of EN 1998--1 : 20041 : 2004Eurocode 8: Design of structures for

earthquake resistanceFOREWORD1 GENERAL

1.1 SCOPE1.2 NORMATIVE REFERENCES1.3 ASSUMPTIONS1.4 DISTINCTION BETWEEN PRINCIPLES AND APPLICATION RULES 1.5 TERMS AND DEFINITIONS1.6 SYMBOLS1.7 S.I. UNITS

2 PERFORMANCE REQUIREMENTS AND COMPLIANCE CRITERIA2.1 FUNDAMENTAL REQUIREMENTS2.2 COMPLIANCE CRITERIA

3 GROUND CONDITIONS AND SEISMIC ACTION3.1 GROUND CONDITIONS 3.2 SEISMIC ACTION

4 DESIGN OF BUILDINGS4.1 GENERAL4.2 CHARACTERISTICS OF EARTHQUAKE RESISTANT BUILDINGS 4.3 STRUCTURAL ANALYSIS4.4 SAFETY VERIFICATIONS

5 SPECIFIC RULES FOR CONCRETE BUILDINGS5.1 GENERAL 5.2 DESIGN CONCEPTS5.3 DESIGN TO EN 1992-1-15.4 DESIGN FOR DCM5.5 DESIGN FOR DCH5.6 PROVISIONS FOR ANCHORAGES AND SPLICES 5.7 DESIGN AND DETAILING OF SECONDARY SEISMIC ELEMENTS 5.8 CONCRETE FOUNDATION ELEMENTS5.9 LOCAL EFFECTS DUE TO MASONRY OR CONCRETE INFILLS 5.10 PROVISIONS FOR CONCRETE DIAPHRAGMS 5.11 PRECAST CONCRETE STRUCTURES

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6 SPECIFIC RULES FOR STEEL BUILDINGS6.1 GENERAL6.2 MATERIALS6.3 STRUCTURAL TYPES AND BEHAVIOUR FACTORS6.4 STRUCTURAL

ANALYSIS 6.5 DESIGN CRITERIA AND DETAILING RULES FOR DISSIPATIVE

STRUCTURAL BEHAVIOUR COMMON TO ALL STRUCTURAL TYPES6.6 DESIGN AND DETAILING RULES FOR MOMENT RESISTING FRAMES6.7 DESIGN AND DETAILING RULES FOR FRAMES WITH CONCENTRIC

BRACINGS6.8 DESIGN AND DETAILING RULES FOR FRAMES WITH ECCENTRIC

BRACINGS 6.9 DESIGN RULES FOR INVERTED PENDULUM STRUCTURES 6.10 DESIGN RULES FOR STEEL STRUCTURES WITH CONCRETE CORES OR

CONCRETE WALLS AND FOR MOMENT RESISTING FRAMES COMBINED WITH CONCENTRIC BRACINGS OR INFILLS

6.11 CONTROL OF DESIGN AND CONSTRUCTION

7 SPECIFIC RULES FOR COMPOSITE STEEL – CONCRETE BUILDINGS

7.1 GENERAL7.2 MATERIALS7.3 STRUCTURAL TYPES AND BEHAVIOUR FACTORS7.4 STRUCTURAL ANALYSIS7.5 DESIGN CRITERIA AND DETAILING RULES FOR DISSIPATIVE

STRUCTURAL BEHAVIOUR COMMON TO ALL STRUCTURAL TYPES7.6 RULES FOR MEMBERS7.7 DESIGN AND DETAILING RULES FOR MOMENT FRAMES7.8 DESIGN AND DETAILING RULES FOR COMPOSITE

CONCENTRICALLY BRACED FRAMES7.9 DESIGN AND DETAILING RULES FOR COMPOSITE ECCENTRICALLY

BRACED FRAMES7.10 DESIGN AND DETAILING RULES FOR STRUCTURAL SYSTEMS

MADE OF REINFORCED CONCRETE SHEAR WALLS COMPOSITE WITH STRUCTURAL STEEL ELEMENTS

7.11 DESIGN AND DETAILING RULES FOR COMPOSITE STEEL PLATE SHEAR WALLS

7.12 CONTROL OF DESIGN AND CONSTRUCTION

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8 SPECIFIC RULES FOR TIMBER BUILDINGS8.1 GENERAL 8.2 MATERIALS AND PROPERTIES OF DISSIPATIVE ZONES8.3 DUCTILITY CLASSES AND BEHAVIOUR FACTORS8.4 STRUCTURAL ANALYSIS8.5 DETAILING RULES8.6 SAFETY VERIFICATIONS8.7 CONTROL OF DESIGN AND CONSTRUCTION

9 SPECIFIC RULES FOR MASONRY BUILDINGS9.1 SCOPE 9.2 MATERIALS AND BONDING PATTERNS9.3 TYPES OF CONSTRUCTION AND BEHAVIOUR FACTORS 9.4 STRUCTURAL ANALYSIS 9.5 DESIGN CRITERIA AND CONSTRUCTION RULES9.6 SAFETY VERIFICATION 9.7 RULES FOR “SIMPLE MASONRY BUILDINGS”

10 BASE ISOLATION10.1 SCOPE10.2 DEFINITIONS 10.3 FUNDAMENTAL REQUIREMENTS10.4 COMPLIANCE CRITERIA10.5 GENERAL DESIGN PROVISIONS10.6 SEISMIC ACTION10.7 BEHAVIOUR FACTOR10.8 PROPERTIES OF THE ISOLATION SYSTEM10.9 STRUCTURAL ANALYSIS10.10 SAFETY VERIFICATIONS AT ULTIMATE LIMIT STATE

ANNEX A (INFORMATIVE) ELASTIC DISPLACEMENT RESPONSE SPECTRUM

ANNEX B (INFORMATIVE) DETERMINATION OF THE TARGET DISPLACEMENT FOR NONLINEAR STATIC (PUSHOVER) ANALYSIS

ANNEX C (NORMATIVE) DESIGN OF THE SLAB OF STEEL-CONCRETE COMPOSITE BEAMS AT BEAM-COLUMN JOINTS IN MOMENT RESISTING FRAMES

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EUROCODE 8 (SEISMIC DESIGN): SPECIFIC RULES FOR CONCRETE

BUILDINGS

Ductility classesDuctility classesNew ductility classes (DC)(changes dictated by national comments supported by a number of background studies)– DC ‘H’ (≈old ‘Μ’, increased q, CD for VSd in beams, ...)– DC ‘Μ’ (≈old ‘L’, increased q, CD for VSd in beams, ...)– DC ‘L’ (EC2, no brittle steel Α, q≤1.5)

Basic value of behaviour factor (q0)

STRUCTURAL TYPE DCH DCM

Frame system, dual system, coupled wall system 4,5αu/α1 3,0αu/α1

Wall system 4,0αu/α1 3,0

Core system 3,0 2,0

Inverted pendulum system 2,0 1,5

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Overstrength – α1 : seismic action at first yield (anywhere)– αu : seismic action at development of overall structural

instability (collapse mechanism)→ Obtained from pushover analysis (αu/α1≤1.5), or defaults:

Frames (or frame-equivalent dual):αu/α1=1.3 (1.1 for one-storey, 1.2 for one-bay frames)Wall (or wall-equivalent dual):− Wall systems with only two uncoupled walls per horizontal direction: αu/α1=1.0− Other uncoupled wall systems: αu/α1=1.1− Wall -equivalent dual, or coupled wall systems: αu/α1=1.2

Final behaviour factor q=qo.kw ≥ 1,5

New structural systemsNew structural systemsLarge lightly reinforced wall system:– comprises at least two walls with horizontal dimension

not less than 4m and 2hw/3, which collectively support at least 20% of the total gravity load above in the seismic design situation

– has a fundamental period T1, for assumed fixity at the base against rotation, less or equal to 0.5sec

– If a structural system does not qualify as a system of large lightly reinforced walls, then all its walls should be designed and detailed as ductile walls

Frame, dual or wall systems without a minimum torsional rigidity (eo<0.3r) should be classified as torsionally flexible (core) systems

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Design criteriaDesign criteriaLocal resistance condition: Ed ≤ Rd

Capacity design rule: Ed from equilibrium conditions, assuming plastic hinges with their possible overstrengths formed in adjacent areas→ to avoid brittle or undesirable failure mechanismsLocal ductility condition: high plastic rotational capacities in potential plastic hinge regions– sufficient curvature ductility (post-failure 85%-moment

resistance level) in all critical regions of primary elementsμφ=2qo-1 if T1≥TC

μφ=1+2(qo-1)TC/T1 if T1<TC

(based on μφ=2μδ-1 and μδ=q if T1≥TC, μδ=1+(q-1)TC/T1 if T1<TC)Note that q<qo for irregular structures (no reduction in μφ,req!)

Structural redundancy: high degree of redundancy accompanied by redistribution capacity (otherwise lower q-factor)Secondary seismic members and resistances: – resistances or stabilising effects not explicitly taken into

account (e.g. membrane reactions of slabs mobilised by upwards deflections of structural walls)

– non-structural elements (esp. masonry infills!)

Specific additional measures (to reduce uncertainty):– minimize geometric errors (min dimensions, max b/h etc.)– minimize ductility uncertainties (min μφ, minρl, νmax)

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Safety verificationsSafety verificationsFor ULS verifications, partial safety factors for materials γc and γs shall account for strength degradation due to the cyclic deformationsγc=1.5 and γs=1.15 (as in EC2) can be taken (convenient for practice!) assuming that – due to local ductility provisions the ratio between the

residual strength after degradation and the initial one is roughly equal to the ratio between the γM-values for accidental and fundamental load combinations

– if strength degradation is appropriately accounted in the evaluation of the material properties, the γM-values adopted for the accidental design situation may be used

Design to Eurocode 2Design to Eurocode 2 (EN1992(EN1992--1)1)

Recommended only for low seismicity areas

In primary elements, reinforcing steel of class B or C (table C.1 EN1992-1) shall be used

Behaviour factor up to q=1.5 may be used in deriving the seismic actions, regardless of the structural system and of regularity in elevation

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Properties of reinforcement (EC2 – Annex C)

Note: The values for the fatigue stress range with an upper limit of β fyk and for the minimum relative rib area for use in a Country may be found in its National Annex. The recommended values are given in Table C.2N. The value of β for use in a Country may be found in its National Annex. The recommended value is 0,6.

Design for DC MDesign for DC M: : Geometrical constraints and materials Geometrical constraints and materials

Material requirements– use of concrete <C16 not allowed in primary elements– use of concrete >C50 (HSC) for DC M is not covered– only ribbed bars are allowed as longitudinal reinforcing

steel in critical regions of primary elements– in primary elements, reinforcing steel of class B or C

(table C.1 EN1992-1) shall be used– welded wire meshes of steel B or C are allowed (should

be ribbed if used as longitudinal reinforcement)

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Geometrical constraintsBEAMS– eccentricity of beam axis < bc/4– width

COLUMNS– unless θ≤0.1, in primary columns b≥0.1lo

(lo: distance from end to point of contraflexure)DUCTILE WALLS– web thickness bwo ≥ max{150mm, hs/20}

(hs: clear storey height) – additional requirements for confined boundary elementsLARGE LIGHTLY REINFORCED WALLS– web thickness bwo ≥ max{150mm, hs/20}

{ }cwcw bhbb 2 ; min +≤

Design for DC MDesign for DC M: : Design action effects Design action effects

Moments and axial forces from analysis, except in primary ductile walls; redistribution of M permittedShear forces from capacity design (shears Vmax,i, Vmin,i calculated for end moments Mi,d)– Beams

(γRd=1.0)),1min(,, ∑

∑=Rb

RciRbRddi M

MMγM

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– Columns

(γRd=1.1)

Ductile walls:– Redistribution between primary walls, up to 30%– Redistribution between coupling beams, up to 20%

),1min(,, ∑∑=

Rc

RbiRcRddi M

MMγM

to account for overstrength due to strain-hardening and confinement

– Design bending moment diagram (slender walls):

al

b a

MEd

M'Ed

al

a

wall systems dual systems

a = from analysisb = design envelopea = tension shiftl

MEd

M'Ed

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– Design shear force diagram (dual systems with slender walls):

designenvelope

ba

(b)

Vwall,base

V >V /2wall,top wall,base

23

13

c

a=from analysisb=magnifiedc=design envelope

hw

hw

Special provisions for large lightly reinforced walls:– to ensure that flexural yielding precedes attainment of

ULS in shear, shear force V′Ed from analysis is increased

– additional dynamic axial forces developed due to uplifting shall be taken into account in the ULS verification (M, N) → may be taken as 50% of the axial force in the wall due to the gravity loads (g+ψ2q)

– if q≤2, these dynamic axial forces may be neglected

21' +

=qVV EdEd

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Design for DC MDesign for DC M: : ULS verifications and detailing ULS verifications and detailing

Beams– bending and shear resistances are computed according

to EN1992-1

2hf2hf hf4hf4hf hf

a c

hf

b 2hf 2hfhf

d

− part of top-reinforcement in T-beams (& Γ-beams) may be placed outside the web, within effective flange width beff

– Detailing of DCM beams for local ductilitycritical regions:

within lcr, μφ,req is provided through:

additional ρ′≥ ½ρ at bottom of supports

tension reinforcement

within lcr, hoops with:

dbw ≥6mm and spacing

s = min{hw/4; 24dbw; 225mm; 8dbL}

hw

lcrlcr

s

<50mm

yd

cd

dsy ff

⋅+=≤,

m ax0018,0'εμ

ρρρφ

⎟⎟⎠

⎞⎜⎜⎝

⎛=≥

yk

ctm

ff5,0m inρρ

0.018?

26

Columns– bending and shear resistances are computed

according to EN1992-1– simplified biaxial bending check with 0.7MRd,uniax

– in primary columns normalised axial force νd ≤0.65– Detailing of DCM columns for local ductility

long. reinforcement ratio 1%≤ ρl≤4%at least one intermediate bar (between corner bars)critical (end) regions:if lcl/hc<3 (short column), the entire height lcl=lcr

within lcr, μφ,req (e.g. =2qo-1) is provided if μφ,req involves εcu≥0.0035 → confinement required!

{ }mm450 ;6/ ;max cllhl ccr =

confinement reinforcement within lcr (DC M)

α.ωwd ≥ 30.μφ 035,0 , −⋅ε⋅ν⋅o

cdsyd b

b

s

bc

ho

hc

bobc

bi

⎥⎦

⎤⎢⎣

⎡⋅=

cd

ydwd f

f

core concrete of volumehoops confining of volumeω

confinement effectiveness factor α=αn⋅αs

for rectangular cross sections:

oon

in hbb 6/1 2∑−=α

( )( )oos hsbs 2/12/1 −−=α min ωwd = 0.08 for circular cross sections with spiral reinforcement:

1=α n

( )os Ds 2/1−=α

27

to prevent early local buckling of longitudinal bars– within lcr : s = min{bo/2; 175mm; 8dbL} – distance between supported bars smax ≤ 200 mm

transverse reinforcement within lcr at the base of primary columns may be determined as specified in EN1992-1, provided that νd ≤ 0.2 and q ≤ 2.0

Beam-column joints– horizontal confinement reinforcement in joints of

primary beams with columns shall not be less than that provided within lcr of columns

– if beams with bw≥bc frame into all four sides of the joint, spacing of horizontal confinement reinforcement in the joint may be increased to twice that required above, but s≤150 mm

– at least one intermediate (between column corner bars) vertical bar shall be provided at each side of a joint of primary beams and columns

28

Ductile walls– bending and shear resistances computed according to

EN1992-1– in primary walls, normalised axial force νd ≤ 0.4– vertical web reinforcement shall be included in

calculation of flexural resistance of wall sections– flexural resistance of composite sections (L, T, U, I or

similar) based on effective flange width, min of:actual flange width ½ distance to adjacent web of the wall 25% of total height of wall above the level considered

– Detailing of DCM walls for local ductilityheight of critical region hcr above the base

required μφ as in columns, but using qo multiplied by MEd/MRd at base of wall (e.g. μφ=2qoMEd/MRd-1), to be provided by confinement of boundary elements

– for walls with rectangular section

– for barbelled walls, N and ωv refer to hcbcfcd if xu≤lc, otherwise analysis with confined concrete model needed

[ ]⎪⎩

⎪⎨

⎧

⎩⎨⎧

≥⋅≤

⋅

≤=

storeys7 n for h2 storeys6 n for h

lhbutH lh

s

s

w

crwwcr

26/max ,

( )cd

vydvv

o

cdsydwd f

fwhere

bb ,

, 035,030 ρωεωνμαω νφ =−+≥

29

confinement of boundary elements should extend

– vertically: over hcr

– horizontally: over lc (assuming εcu2=0.0035)

– minlc≥ {0,15⋅lw or 1,50.bw}no confined boundary element is required over wall flanges with thickness hf >hs/15 and width bf > hs/5

not good practice

in boundary elements: minρl=0.5% (=½ minρl,col)

thickness bw≥200, also:

above hcr EC2 applies,but if εc>0.002, minρl=0.5%

ωw in boundary elements may conform to EC2 only, if:– axial load νd ≤ 0.15– axial load νd ≤ 0.20 and q reduced by 15%

30

Large lightly reinforced walls– bending resistances computed according to EN1992-1

– when VEd≤VRd,c=[CRd,ck(100ρl fck)1/3 + 0.15σcp]bwdρw,min in the web is not required

– sliding shear check is done according to EN1992-1, but anchorage length of clamping bars increased by 50%

– hoop and cross-tie vertical spacing ≤min{100mm, 8dbL)– vertical bars engaged by hoop or cross-tie with d≥6mm,

within boundary elements with lc ≥min{bw 3bwσcm/fcd}, (σcm: mean value of concrete stress in compression zone)

– horiz. + vert. ties according to EN1992-1 providedalong all intersections of wallsaround openings in the wall at all floor levels

Design for DC HDesign for DC Hgenerally similar to DCM, but more stringent detailingmore detailed verification of beam-column jointsif , cross-inclinedreinforcement required to resist shear in beamsexplicit calculation of joint resistance

explicit calculation of sliding shear resistance of walls

( ) dbfVV wctdEEd ⋅⋅⋅+=> ζ2max

cj d

cdjhd hbfVη

ν−η≤ 1

ctdcddctd

jcj

jhd

jwj

ywdsh fff

hbV

hbfA

−ν+

⎟⎟⎠

⎞⎜⎜⎝

⎛

⋅≥

⋅

⋅

2

fdidddSRd VVVV ++=,

⎪⎩

⎪⎨⎧

Σ⋅⋅

⋅⋅Σ⋅=

sjyd

ydcdsjdd

Af

ffAV

25,0

3,1min

ϕ⋅⋅Σ= cosydsiid fAV

( )[ ]⎩⎨⎧

⋅⋅ξ⋅⋅ν

+ξ⋅+⋅Σ⋅μ=

wowcd

EdSdydsjffd blf

zMNfAV

5,0

/min

31

Provisions for anchorages and splicesProvisions for anchorages and splices– hoops should be closed stirrups with 135° hooks and

10dbw long extensionsAnchorage of reinforcement Columns– anchorage length lbd of column bars in critical regions

based on As,req/As,prov = 1– first 5dbL of column bar within a joint not included in lbd

– if NEd is tensile in a column, lbd increased by 50%Beams– the part of beam bars bent in joints for anchorage should

be placed inside the corresponding column hoops

– to prevent bond failure → limit dbLpassing through joints

interior beam-column joints

exterior beam-column joints

– if limit on dbL difficult to satisfy, use special measures

– top or bottom bars passing through interior joints, shall terminate at distance ≥ lcr from the face of the joint

max/'75.018,015,7

ρρ⋅+ν⋅+

⋅⋅γ

⋅≤

D

d

ydRd

ctm

c

bLkf

fh

d

( )dydRd

ctm

c

bLf

fh

dν⋅+⋅

⋅γ⋅

≤ 8,015,7

1.01.2γRd

2/31kD

DC MDC H

32

Additional measures for Additional measures for anchorage in exterior anchorage in exterior beambeam--column jointscolumn joints

lb > 5d for DCHbL

hc

anchorplate

hc

hoops aroundcolumn bars

d >0.6dbw bl

dbl

> 10

dbl

a) exterior stubs

b) plates welded to end of bars

c) transverse bars inside the bend

Splicing of reinforcement – lap-splicing by welding not allowed within the lcr

– splicing by mechanical couplers allowed in columns and walls, if covered by appropriate (cyclic) testing

– spacing of transverse reinforcement in the lap zone:s = min{b/4; 100mm}

– required area of transverse reinforcement Ast within the lap zone ( )( )ywdyl, dblst /ff/ds A 50=

area of one leg of transverse reinforcement

33

Design and detailing of secondary Design and detailing of secondary seismic seismic elementselements

designed/detailed to maintain bearing capacity, when subjected to max deformations under seismic actionsdoes not apply to non-seismic members (e.g. slab ribs)max deformations calculated from analysis, in which the contribution of secondary elements to lateral stiffness is neglected and primary elements are modelled with their cracked flexural and shear stiffnessverification: Md≤MRd and Vd≤VRd where Md, Vdcalculated from above max deformations and cracked flexural and shear stiffness of secondary elements

Local effects due to masonry or Local effects due to masonry or concrete infillsconcrete infills

the entire length of columns in infilled ground floorsconsidered as critical length and confined accordinglyif hinf<lcl,col, lcr=lcl plus special measures:– design shear calculated from CD based on lcl and γRdMRc

– corresponding ties placed within lcl+hc

– if ‘free’ length < 1.5hc, diagonal reinforcement needed

if masonry infill on one side of column only, lcr=lcl

length lc of column over which the diagonal strut force of the infill is applied, should be verified in shear for min of horiz. component of strut force and CD shear

34

SSeismic performance of multistorey eismic performance of multistorey R/CR/Cbuildings designed to the prbuildings designed to the prENEN--19981998--11: :

Trial application of the new provisions to four typical multi-storey buildings, 6-storey and 10-storey

– with reinforced concrete (R/C) frame system – with dual (frame+wall) system

Similar buildings previously designed (Kappos / Athana-ssiadou, EEE, 1997) for old ductility classes H and M– comparisons between the old and new designs– in terms of cost of materials and of seismic performance

Design of 6Design of 6--storey buildings storey buildings

Codes:EC2 , EC8 (prEN)Materials:C20/25 S400

Design PGA:αg=0.25Code spectrum Type 1(Μs>5.5)Effective Stiffness:EIeff=0.5EIg

35

Behaviour factorsBehaviour factors qq

q=1.5, for DC “L”q= kw·qo, for DC “M” and “H”- frame system / DC “M”: q=3.90- dual system / DC “M”: q=3.6- frame system / DC “H”: q=5.85- dual system / DC “H”: q=5.40

→ Very similar q-factors for both systems!

detailing of frame system / DCdetailing of frame system / DC““LL””

4Φ16

2Φ14

4Φ16

2Φ10

Φ6/170

Φ6/165

2Φ162Φ14

4Φ16

Φ6/210

2Φ14

2Φ16 1Φ14

2Φ10

Φ6/110

4Φ16

4Φ14

3Φ14

3Φ16

Φ6/195

4Φ16

4Φ14

2Φ16 2Φ14

2Φ14

4Φ16

3Φ14

Εξωτερική στήριξη δοκού 1ου-2ου ορόφου

2Φ14

Φ6/115



Εσωτερική στήριξη δοκού 1ου-2ου ορόφου



εξωτερικό υποστύλωμα 5ου - 6ου ορόφου

εσωτερικό υποστύλωμα 5ου - 6ου ορόφου Φ8/180

Φ8/190

2Φ18

2Φ16


2Φ16

2Φ18

Φ8/215

4Φ20

4Φ20

Φ8/105

Φ8/1553Φ20

3Φ20

εσωτερικό υποστύλωμα 3ου ορόφου

εσωτερικό υποστύλωμα 1ου - 2ου ορόφου

2Φ18

2Φ18

4Φ20

4Φ20

εσωτερικό υποστύλωμα 4ου ορόφου

Φ8/215

2Φ18

4Φ20

4Φ20 2Φ18

1Φ16 2Φ18

2Φ181Φ16

2Φ22

2Φ22


Φ8/210

3Φ18

3Φ18

36

detailing of frame system / DCdetailing of frame system / DC ““MM””

2Φ14

3Φ16

εξωτερική στήριξη δοκού 3ου - 4ου ορόφου

Φ6/110

2Φ14

3Φ16

Φ6/110



2Φ14

3Φ14

Φ6/110

εσωτερική στήριξη δοκού 5ου - 6ου ορόφου



3Φ14

3Φ14

Φ6/110

2Φ14

Φ6/110

3Φ14

Φ6/110

2Φ16

2Φ16

3Φ14

2Φ16 2Φ14

4Φ18

4Φ18



4Φ18

4Φ18

Φ8/120

Φ6/120

2Φ20

1Φ18

1Φ18

2Φ20


Φ6/140

2Φ18

1Φ16




1Φ16

2Φ18

Φ8/100

Φ6/100

2Φ181Φ16

1Φ162Φ18

Φ6/1103Φ14

3Φ14

detailing of frame system / DCdetailing of frame system / DC ““HH””

2Φ14 2Φ12

2Φ14

Φ6/70

3Φ14

2Φ14

Φ6/80

4Φ12

3Φ12

Φ6/70

4Φ14

2Φ14

4Φ14

2Φ14

6Φ12

3Φ12







Φ6/80

Φ6/80

Φ6/70

Πόδας εσωτερικού υποστυλώματος 1ου ορόφου

4Φ20

4Φ20

Φ8/100

Κεφαλή εσωτερικού υποστυλώματος 1ου- 2ου ορόφου

4Φ20

4Φ20

Φ8/120

4Φ18

4Φ18

Φ8/105

2Φ20 1Φ18

2Φ201Φ18

Φ8/105

Φ8/90

1Φ182Φ20

1Φ182Φ20

Φ8/105

1Φ182Φ20

1Φ16

2Φ20

Εσωτερικό υποστύλωμα 3ου - 4ου ορόφου

Φ8/90

2Φ18

2Φ181Φ16

3Φ14

3Φ14Φ6/75

1Φ18

Εσωτερικό υποστύλωμα 5ου - 6ου ορόφου

Πόδας εξωτερικού υποστυλώματος 1ου ορόφου

Κεφαλή εξωτερικού υποστυλώματος 1ου- 2ου ορόφου

Εξωτερικό υποστύλωμα 3ου - 4ου ορόφου

Εξωτερικό υποστύλωμα 5ου - 6ου ορόφου

37

detailing of dual system / DC detailing of dual system / DC ““LL””

2Φ10

Φ6/180

2Φ16 2Φ14

2Φ16 1Φ14

Φ6/175

4Φ16

3Φ16

4Φ16

3Φ16

Φ6/175

2Φ16 2Φ14

Φ6/160

Φ6/145

Φ6/150

5Φ16

3Φ14

5Φ16

4Φ14

4Φ16

2Φ16 2Φ14

4Φ14

1Φ144Φ16

2Φ10







3Φ12

3Φ12

Φ8/140

υποστύλωμα 1ου - 2ου ορόφου


Φ8/1402Φ12

2Φ14 2Φ12

2Φ14

4Φ14

4Φ14

Φ8/165


detailing of dual system / DC detailing of dual system / DC ““LL””

τοίχωμα 1ου ορόφου

4Φ8/m²


4Φ8/m²


4Φ8/m²


4Φ8/m²

τοίχωμα 5ου - 6ου ορόφου

4Φ8/m²

Φ8/190Φ12/170

Φ10/300 Φ8/210

Φ10/300 Φ8/240

Φ10/300 Φ8/300

Φ10/300 Φ8/400

Φ8/210

Φ8/190 Φ8/4007Φ18

Φ ²

4Φ14

4Φ14 Φ8/245

4Φ14

4Φ14 Φ8/400

Τοίχωμα 5ου - 6ου ορόφου

Τοίχωμα 4ου ορόφου




Φ8/400

Φ8/400

Φ8/400

Φ8/400

Φ8/305

Φ ²

Φ ²

Φ ²

Φ ²

38

detailing of dual system / DC detailing of dual system / DC ““ΜΜ””

2Φ14 2Φ12

2Φ14

Εξωτερική στήρίξη δοκού 1ου-2ου ορόφου

Φ6/95

4Φ16

2Φ16

3Φ16 2Φ14

3Φ14

3Φ14

2Φ16 3Φ14

Φ6/125

Φ6/110

Φ6/110




Φ6/95

2Φ14

2Φ122Φ14


2Φ14


2Φ14 2Φ12

Φ6/95

2Φ18 1Φ16

2Φ18

1Φ16

Φ8/115

Φ6/1101Φ162Φ18

1Φ162Φ18

2Φ181Φ16

Φ6/125

2Φ18 1Φ16

Υποστύλωμα 1ου-2ου ορόφου



detailing of dual system / DC detailing of dual system / DC ““MM””

Φ ²

Φ ²

8Φ14Φ8/150 Φ8/300 Φ8/400

Φ8/400Φ8/300Φ6/60 8Φ14

Φ ²

Τοίχωμα 1ου ορόφου (1ος τρόπος όπλισης)


4Φ12 Φ8/300Φ8/330

Φ8/300


Φ8/3704Φ12

Φ ²

Φ8/300

Τοίχωμα 4ου-6ου ορόφου

Φ8/4004Φ12

Φ ²

Τοίχωμα 1ου ορόφου (2ος τρόπος όπλισης)

39

detailing of dual system / DC detailing of dual system / DC ““ΗΗ””εξωτερική στήριξη δοκού

2Φ12

Φ6/70

2Φ14


2Φ14

3Φ12

Φ6/70

2Φ14

3Φ12

2Φ16 2Φ14

3Φ14

Φ6/70


Φ8/80

2Φ18

1Φ16

υποστύλωμα πόδας ισογείου

1Φ16

2Φ18

2Φ18

1Φ16

1Φ16

2Φ18

υποστύλωμα κεφαλή ισογείου

Φ8/90

2Φ18

1Φ16

1Φ16

2Φ18

υποστυλώματα 2ου - 6ου ορόφου

Φ8/90

4Φ8/m²Φ

4Φ8/m²

Φ

4Φ8/m²

12Φ14

4Φ8/m²

8Φ14

4Φ12

4Φ12





Φ8/200

Φ8/200

Φ8/200

Φ8/200

Φ8/130

Φ8/145

Φ8/145

Φ8/175

Quantities of materialsQuantities of materials

52,559

35,013 37,24

0

10

20

30

40

50

60

DC "L" DC "M" DC "H"

Βάρος συνολικού οπλισμού πλαισιακών συστημάτων

28,12725,39

29,809

0

10

20

30

40


Βάρος συνολικού οπλισμού διπλών συστημάτων

38,29236,033

37,9

0

10

20

30

40


Όγκος σκυροδέματος πλαισιακών συστημάτων

46,704 45,054 45,054

0

10

20

30

40

50


Όγκος σκυροδέματος διπλών συστημάτωνconcrete volume in frame concrete volume in dual

total reinforcement in frame total reinforcement in dual

40

Design of 10Design of 10--storey buildings for DC storey buildings for DC ““HH””FR FR (T=0.96s)(T=0.96s) FW FW (T=0.64s)(T=0.64s)

q=5.85 q=5.40PGA=0.25g, C20/25 concrete, S400 steel

Required quantity of materials in the Required quantity of materials in the frameframe structuresstructures

19.24

25.21 27.18

0

5

10

15

20

25

30

new DC H old DC M old DC H

66.979.7 80.92

0153045

607590


47.6654.49 53.47

0

15

30

45

60

75


19.24

25.21 27.18

0

5

1015

20

25

30


Concrete volume Total weight of reinforcement

Weight of longit. reinforcement Weight of transv. reinforcement

41

Required quantity of materials in the Required quantity of materials in the dualdual structuresstructures

Concrete volume Total weight of reinforcement

Weight of longit. reinforcement Weight of transv. reinforcement

58.74 59.48 60.7

0

15

30

45

60

75


55.7365.16 64.42

0

15

30

45

60

75


32.48

40.837.07

0

10

20

30

40

50


23.25

25.06

27.35

20

22

24

26

28


Design to new DCDesign to new DC’’HH’’ results in:results in:

16% less reinforcement in the frame (FR)14% less reinforcement in the dual (FW)Longitudinal reinforcement: 11 to 20% lessTransverse reinforcement: 7 to 29% less9% less concrete volume in the frame (FR)2% less concrete volume in the dual (FW)

→ Main reason for reduced steel requirements:higher q-factors specified by the prEN

42

Seismic performance assessmentSeismic performance assessmentModelling: Standard point hinge (DRAIN-2D/2000)

Takeda model for members with N≅const.Bilinear with My-N interaction if N=n(t)

Failure criteriaLocal (member failure)

(i) Rotational capacity check: θp = kV (φu - φy) (kμ lpo)(ii) Shear force exceeding the corresponding capacity of the member

at the maximum ductility levelGlobal (storey failure): Dual criterion based on

(i) limiting interstorey drift of 2% and (ii) simultaneous development of a sidesway collapse

mechanism

Input motions: 6 records from Greece (from 3 earthquakes)→ scaled to modified spectrum intensity (SIm)

Interstorey drift ratios for frame structures

comparison with the old EC8 (A=0.25g)

mean and max drifts for new DC H frame

0123456789

10

0.0 0.4 0. 8 1.2 1.6Δx /h (% )

M ean (A =0.25g)M ax im um (A= 0. 25g)M ean (A =0.50g)M ax im um (A= 0. 50g)

0123456789

10

0.0 0.2 0.4 0.6 0.8

Δx/h (%)

new DC Hold DC Mold DC H

43

Required and available plastic rotations in the exterior Required and available plastic rotations in the exterior columns of FR for the most critical motioncolumns of FR for the most critical motion

0

1

2

3

4

5

6

7

8

9

10

0. 00 0.02 0.04 0. 06 0.08

θp,req (A=0,25g) θp, av (A= 0,25g)θp,req (A=0,50g) θp, av (A= 0,50g)

0

1

2

3

4

56

7

89

10

0.00 0.02 0.04 0.06 0.08 0.10

θp,req (new DC H) θp,av (new DC H)θp,req (old DC M) θp,av (old DC M)θp,req (old DC H) θp,av (old DC H)

performance of the new DC H frame comparison with the ‘old’ EC8 (A=0.25g)

min θp,av/θp,req = 5.4

Required and available plastic rotations in the interior Required and available plastic rotations in the interior beams of FR for the most critical motion beams of FR for the most critical motion

0

1

2

3

4

5

6

7

8

9

10

0 0.01 0.02 0.03 0.04 0.05 0.06

θp+,req (new DC H) θp+,av (new DC H)θp+,req (old DC M) θp+,av (old DC M)θp+,req (old DC H) θp+,av (old DC H)

0

1

2

3

4

5

6

7

8

9

10

0 0.005 0.01 0.015 0.02 0.025


positive values negative values

44

Required and available shear capacities (in kN) in the Required and available shear capacities (in kN) in the columnscolumns of FR for the most critical motionof FR for the most critical motion

0

1

2

3

4

5

6

7

8

9

10

0 200 400 600 800

Vmax (A=0.25g) VR (A=0.25g)Vmax (A=0.50g) VR (A=0.50g)

0

1

2

3

4

5

6

7

8

9

10

0 200 400 600 800 1000

Vmax (new DC H) VR (new DC H)Vmax (old DC M) VR (old DC M)Vmax (old DC H) VR (old DC H)

performance of the new DC H frame comparison with the old EC8 (A=0.25g)

Required and available shear capacities (in kN) in the Required and available shear capacities (in kN) in the beamsbeams of FR for the most critical motionof FR for the most critical motion

0

1

2

3

4

5

6

7

8

9

10

0 100 200 300 400

Vmax (A=0.25g) VR (A=0.25g)Vmax (A=0.50g) VR (A=0.50g)

0

1

2

3

4

5

6

7

8

9

10

0 100 200 300 400

Vmax (new DC H) VR (new DC H)Vmax (old DC M) VR (o ld DC M)Vmax (old DC H) VR (old DC H)

performance of the new DC H frame

comparison with the old EC8 (A=0.25g)

45

Percentage of the dissipated energy in the Percentage of the dissipated energy in the structural members of the frame structurestructural members of the frame structure

4.6412.15 14.61

23.22

80.75

64.63

0

20

40

60

80

100

ext. columns int. columns beams

A=0.25g A=0.50g

Interstorey drift ratios for Interstorey drift ratios for dualdual structuresstructures

0123456789

1 0

0 . 0 0 . 2 0 . 4 0 . 6 0 . 8Δ x /h (% )

M ea n ( A= 0 .2 5 g )M ax imu m (A= 0 .2 5g )M ea n ( A= 0 .5 0 g )M ax imu m (A= 0 .5 0g )

0

1

2

3

4

5

6

7

8

9

10

0 . 0 0 . 2 0 . 4 0 . 6Δ x /h (% )

n ew D C Ho ld D C Mo ld D C H

mean and maximum drifts for the new

DC H frame comparison with the old EC8 (A=0.25g)

46

Required and available plastic rotations in the vertical Required and available plastic rotations in the vertical elements of FW for the most critical motion (A=0.25g)elements of FW for the most critical motion (A=0.25g)

0

1

2

3

4

5

6

7

8

9

10

0.00 0.01 0.02 0.03 0.04

θp,req (new DC H) θp,av (new DC H)θp,req (old DC M) θp,av (old DC M)

θp,req (old DC H) θp,av (old DC H)

0

1

2

3

4

5

6

7

8

9

10

0.00 0.02 0.04 0.06 0.08

θp,req (new DC H) θp,av (new DC H)θp,req (old DC M) θp,av (old DC M)θp,req (old DC H) θp,av (old DC H)

wall columns

Required and available plastic rotations in the beams of Required and available plastic rotations in the beams of FW for the most critical motionFW for the most critical motion

0

1

2

3

4

5

6

7

8

9

10

0.00 0.01 0.02 0.03 0. 04 0.05 0. 06


0

1

2

3

4

5

6

7

8

9

10

0.000 0.005 0.010 0. 015 0. 020 0.025

θp-,req (new DC H) θp-,av (new DC H)

θp-,req (old DC M) θp-,av (old DC M)θp-,req (old DC H) θp-,av (old DC H)

positive values negative values

47

Required and available shear capacities (in kN) in the Required and available shear capacities (in kN) in the structural elements of FW for the most critical motion structural elements of FW for the most critical motion

(A=0.25g)(A=0.25g)

0

1

2

3

4

5

6

7

8

9

10

0 500 1000 1500 2000

Vmax (new DC H) VR (new DC H)

Vmax (old DC M) VR old (DC M)

Vmax (old DC H) VR (old DC H)

0

1

2

3

4

5

6

7

8

9

1 0

0 200 40 0 600 800

Vm ax (new D C H) VR (new DC H)

Vm ax (old DC M) VR (old D C M)Vm ax (old DC H) VR (old D C H)

wall

columns

0

1

2

3

4

5

6

7

8

9

10

0 100 200 300 400 500

Vmax (new DC H) VR (new DC H)Vmax (old DC M) VR (old DC M)Vmax (old DC H) VR (old DC H)

beams

Percentage of the dissipated energy in the Percentage of the dissipated energy in the structural members of the dual structurestructural members of the dual structure

2.536.88

22.1627.48

75.31

65.64

0

20

40

60

80

100

columns wall beams

A=0.25g A=0.50g

48

CONCLUSIONSCONCLUSIONSDesign of R/C buildings for new DC H (prEN1998-1) appears generally adequate since:– seismic performance of both the frame and dual

systems subjected to design earthquake was satisfactory with regard to all critical response parameters, i.e.

deflections and driftsrotational ductility demandsshear capacity

– the buildings behaved satisfactorily even for twicethe design earthquake (related to collapse prevention requirement)

– largest amount of input seismic energy dissipated in the beams even for the ‘collapse prevention earthquake’

CONCLUSIONSCONCLUSIONS ((contnd.contnd.))

Seismic performance: prEN version satisfactory, generally similar to that of ENV designs, without being over-conservative mainly with regard to the design of the vertical elements for the high ductility (DC H) class.Economy: designing to the new EC8 for DC’H’appears to be more cost-effective than to previous versions, since – volume of concrete was (slightly) lower – quantity of reinforcement (longitudinal, as well as

transverse) were lower than in the ENV design; – main reason: combination of higher q-factor with less

stringent detailing requirements in the new DC H.

Development and basic aspects of EN 1992 and EN...

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