TN10 on Seismic Design FINAL - AEFAC · 2020. 11. 2. · For the ultimate limit state seismic load...

PREQUALIFICATION & DESIGN REQUIREMENTS FOR FASTENINGS UNDER SEISMIC ACTIONS

Ver.1.0October2020

TECHNICAL NOTE

AEFAC–TN10

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TECHNICAL NOTE: PREQUALIFICATION & DESIGN REQUIREMENTS FOR FASTENINGS

UNDER SEISMIC ACTIONS

1. General ThisTechnicalNoteoutlinestheprequalificationanddesignrequirementsforpost-installedfastenersinconcreteusedtotransmitseismicactionsbymeansoftension,shear,oracombinationoftensionandshearloadsbetweenstructuralconnectionsornon-structuralconnections.Thefollowingconnectiontypesaredefinedas:

• Structural connections: These are the connection between structuralelements.

• Non-structural connections: These are the connection between non-structuralpartsandcomponentstostructuralelements.

ThisTechnicalNoteconsistsoftwoparts:• Part A (Sections 4-6): Background information about the prequalification

requirementsoffastenersforseismicactions.• PartB(Sections7-11):Designprovisionsforprequalificationrequirements

anddesignoffastenersforseismicactions.

ThebasisforthedesignrequirementsofthisTechnicalNotearepredominantlyfromEN1992-4(CEN,2018).

Fastenersusedtoresistseismicactionsshallmeetallrelevantrequirementsfornon-seismic actions. Fasteners must be prequalified for cracked concrete and wherenecessary for seismic applications. The level of prequalification for seismicapplications is defined via seismic performance categories. The minimumrecommendedseismicperformancecategoriesforfastenersisprovidedinSection7.The suitability of the fasteners for cracked concrete and seismic performancecategoriesshallbestatedinaprequalificationdocument.ThetestingandassessmentofthefastenersshallbedoneinaccordancewithAS5216(StandardsAustralia,2018)andTR049(EOTA,2016b)forseismicapplications.

2. Scope ThisTechnicalNoteshouldbeconsideredforstructuresandnon-structuralpartsandcomponentswhicharerequiredtobedesignedforearthquakeactionsinaccordancewithAS1170.4(StandardsAustralia,2007).

CrackedconcreteshallbeassumedforthedeterminationofdesignresistanceunlessprovenotherwiseinaccordancewithAS5216.

Loosening of the nuts or screws shall be prevented. The annular gap between afasteneranditsfixtureshallbeconsideredinaccordancewithSection10.

For the ultimate limit state seismic load combination where the seismic designtensionforcesinasinglefasteneroragroupoffastenersisnotgreaterthan20%of

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thetotaldesigntensionforceforthesameloadcombination,itshallbepermittedtodesign the fastener or group of fasteners without following the provisions inSection8.

Fortheultimatelimitstateseismicloadcombinationwheretheseismicdesignshearforcesinasinglefasteneroragroupoffastenersisnotgreaterthan20%ofthetotaldesign shear force for same load combination, it shall be permitted to design thefastenerorgroupoffastenerswithoutfollowingtheprovisionsinSection8.

Furthermore, the provisions of this Technical Note:

• Do not cover the design of fasteners in region of concretememberswhereconcretespallingoryieldingofreinforcementmaytakeplaceduringseismicactions.Theseregionsareoftenreferredtoasplastichingeregionsorzonesfor flexural concrete members. The length of plastic hinge regions can bedeterminedfromanalysisoftherelevantstructureandmember.Examplesofestimationof the lengthofplastichingeregionscanbe found inEN1998-1(CEN, 2004) or ACI 318 (ACI, 2019). Further explanation is provided inSection4.

• Donotcoverseismicdesignofcast-infastenersincludinganchorchannels.Itis noted that cast-in fasteners which rely on bearing would typically havegreatertolerancetocrackwidthandcrackopeningandclosingoftheconcretesubstratecomparedtopost-installedfasteners.Proprietarycapacitiesofcast-infastenersforseismicapplicationswouldtypicallybeprovidedbyrelevantsuppliers.

• Donotcoverseismicdesignofpoweractuatedfasteners.• Donotcoverfasteningswithshear loadsactingonthefastenerwitha lever

armorwithagroutlayerwiththickness≥ 0.5𝑑.

3. Notation 𝑁∗ = Designtensionforceonthefastenersincludingseismic

effectsforthecorrespondingfailuremodes𝑁"#,%&,'%( = Reducedcharacteristicseismicresistanceofafastening

undertensionloads𝑁"#,%& = Characteristic seismic resistance of a fastening under

tensionloads𝑁"#,) = Characteristictensilestrengthofafasteneroragroupof

fasteners to anchorage failure of supplementaryreinforcement

𝑁"#,* = Characteristictensilestrengthofafasteneroragroupoffastenerstoconcreteconefailure

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𝑁"#,*+ = Characteristictensilestrengthofafasteneroragroupoffastenerstoconcreteblow-outfailure

𝑁"#,,,%& = Characteristicresistanceoffastenersinseismictension(Subscriptirepresentsthedifferentfailuremodes)

𝑁"#,- = Characteristictensilestrengthofafasteneroragroupoffastenerstopull-outfailure

𝑁"#,'% = Characteristictensilestrengthofafasteneroragroupoffasteners to steel failure of supplementaryreinforcement

𝑁"#,. = Characteristictensilestrengthofafastenertosteelfailure𝑁"#,.- = Characteristictensilestrengthofafasteneroragroupof

fastenerstoconcretesplittingfailure𝑅(,%& = Seismicdesignresistanceofafastener𝑅#,*/0*,%& = minimum design characteristic seismic resistance for

allconcreterelatedfailuremodes𝑅#,%& = Characteristicseismicresistanceofafastener𝑅#,%&1 = Basic characteristic seismic resistance for a given

failuremode𝑅#,.,%& = Minimum characteristic seismic resistance for steel

failure𝑆2∗ = Designedloadinthehighestloadedfastenerinthegroup𝑆3∗ = Designedloadinthegroupoffasteners𝑆- = Structural performance factor in accordance with AS

1170.4𝑉∗ = Designshearforceonthefastenersincludingseismic

effectsforthecorrespondingfailuremodes

𝑉"#,%&,'%( = Reduced characteristic seismic design resistance of afasteningundershearloads

𝑉"#,* = Characteristic shear strength of a fastener or a group offastenerstoconcreteedgefailure

𝑉"#,,,%& = Characteristic resistance of fasteners in seismic shear(Subscriptirepresentsthedifferentfailuremodes)

𝑉"#,. = Characteristicshearstrengthofafastenertosteelfailure𝑉"#,*- = Characteristic shear strength of a fastener or a group of

fastenerstopry-outfailure𝑍 = Earthquake hazard design factor in accordance with AS

1170.4𝑑 = Diameteroffastenerboltorthreaddiameterofthestud𝑓45 = Ultimatetensilestrengthoffastener𝑓65 = Yieldtensilestrengthoffastener𝑘- = TheprobabilityfactorinaccordancewithAS1170.4

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𝑠7)8 = Distance between the outermost rowof fasteners andoppositeedgeofthefixture

𝛼%& = Factor to take into account the influence of seismicactionsandassociatedcracking

𝛼3)- = Reductionfactortotakeintoaccountforinertiaeffectsduetoanannulargapbetween fastenerand fixture incaseofshearloading

𝛾,0.9 = Factortakinginaccountthesensitivitytoinstallation𝛿:,%&(<=>) = Displacementof the fastenerunder tension loadingat

DLS𝛿:,%& = Displacementofthefastenerunderseismicloading𝛿:,'%&(<=>) = Required displacement of the fastener under tension

loadingatDLS𝛿@,%&(<=>) = DisplacementofthefastenerundershearloadingatDLS𝛿@,'%&(<=>) = Required displacement of the fastener under shear

loadingatDLS𝜃- = Rotationoftheconnection𝜙𝑖 = Capacity reduction factor for strength of fastener or

fastenergroupforfailuremodei𝜙𝑖𝑛𝑠𝑡 = Capacityreductionfactorforinstallation,𝜙𝑖𝑛𝑠𝑡 =

1𝛾𝑖𝑛𝑠𝑡

𝜇 = StructuralductilityfactorinaccordancewithAS1170.4C1 = Seismicperformancecategory1C2 = Seismicperformancecategory2DLS = DamagelimitstateULS = Ultimatelimitstate

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PartA

BackgroundInformation

4. Introduction Post-installedfastenersinconcretedonothavepredictablecapacitiesforallpossiblefailuremechanismsandrequireprequalificationwhichinvolvestestsandassessmentprocedures to define their performance. Significant research has been conductedinternationally, including Europe and the USA, to develop prequalificationrequirementsforfastenerswhichhasresultedindifferentlevelsofprequalificationbased on the application of the fasteners (Eligehausen et al., 2006; Hoehler &Eligehausen,2008;Hoeler,2006;Mahrenholtzetal.,2017).Underseismicactionsithas been highlighted that the performance of post-installed fasteners is highlydependentonthedamagestateoftheconcretesubstratewhichisrelatedtoexpectedcrackwidthsandtheopeningandclosingnatureofthecrack.

TherequirementsdiscussedinthisTechnicalNoteareapplicableforfastenersthatare located outside of regions where yielding of reinforcement and spalling ofconcrete may occur. For flexural members this corresponds to the plastic hingeregions.Intheory,thelengthofplastichingeregions(𝑙6)correspondstotheregionforwhichtheyieldcurvature(𝜙6)isexceededasillustratedinFigure1.Plastichingeregionsextendforadistanceof𝑙6frombeamandcolumnfaces,andinothersectionssuch as walls, slabs, and frames where yielding of reinforcementmay take placeunderseismicactions. It’snoted that 𝑙6 isdifferent to theequivalentplastichingelength (𝑙-) which is obtained from the idealised curvature distribution forapproximatingtheultimatedisplacementcapacityofstructuralelements.Thelengthofplastichingeregionsishighlydependentonthedetailingofmembers.Asaguide,the suggested plastic hinge lengths for the purpose of detailing primary seismiccomponents inEN1998-2(CEN,2004)formediumandhighlevelsofductilityareprovided in Table 1. Furthermore, the suggested length for positioning fastenersoutsideofplastichingeregionsinaccordancewiththecommentaryofACI318(ACI,2019)hasbeenprovided.

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Figure1:Plastichingeformationofasinglecurvatureflexuralelement

(𝜙! ,𝜙",𝜙#areyield,plastic,andultimatecurvaturerespectively,𝑀!and𝑀#areyieldandultimatemomentrespectively)

Table1:RecommendedplastichingelengthsfordetailingofprimaryseismiccomponentsinEN1998-1andforfastenerlocationinACI318

MemberEN1998-1(2004) ACI318(2019)

Mediumductilityclass

Highductilityclass

Commentary

Beam l$ = h% l$ = 1.5h% l$ = 2h%

Forbeamssupportingdiscontinuedverticalelementsl$ = 2h%oneachsideof

thesupportedverticalelement

Columns

l$ = max.

h&l&'6

0.45m

2 l$ = max.

1.5h&l&'6

0.6m

2l$ = 2h&

If'!(≤ 3,l$ = l&

Wallsl$ = max 5

l)*"+6,but

l$ ≤ 72l)h,forn ≤ 6storey2h,forn ≥ 7storey

B

Notspecified

ℎ#isthebeamdepth|ℎ$isthelargestcross-sectionaldimensionofthecolumn|𝑙$%istheclearheightofthecolumn|ℎ&istheclearstoreyheight|𝑙'isthelengthofthewallcross-section|ℎ'istheheightofthewall

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5. Prequalification requirements InEurope,forstaticandquasi-staticactions,theprequalificationtestsareconductedfor reliability and service-conditions of the structure which are dependent onwhether the fasteners are to be used in cracked or uncracked concrete. TheprequalificationrequirementsarestatedinEuropeanAssessmentDocuments(EAD),including:EAD330232(EOTA,2016a)formechanicalfasteners,EAD330499(EOTA,2017) for bonded fasteners, andEAD330747 (EOTA, 2018) for fasteners used inredundantnon-structuralsystems.Forservice-loadconditionsofthestructure,thefasteners are tested in cracked concrete with maximum crack widths ofapproximately 0.3mm. This generally corresponds to themaximum crackwidthsrecommendedforserviceabilityrequirements.

Since2013Europeintroducedtwoseismicperformancecategories;C1andC2.ThetestingproceduresandassessmentcriteriaarestatedintheTechnicalReport,TR049(EOTA, 2016b). The prequalification tests for C1 involve pulsating tension andalternatingshearloadingofthefastenerinastaticcrackwithamaximumwidthof0.5mm. For C2, in addition to testing the fastener under a pulsating tension andalternating shear loading in a static crackwith amaximumwidth of 0.8mm, thefastenerisloadedintensionincrackcyclingconditionstosimulatetheopeningandclosing nature of cracks during seismic loading under moment reversals.Furthermore,afastenerexhibitingpull-outorpull-thoughbehaviourisnotsuitableforC2performancecategory.Hence,theprequalificationrequirementsforC2ismoredemandingthanC1.Thecrackwidthlimitsforseismicapplicationsarebasedontherequirementthatthefastenerswillbelocatedoutsideoftheplastichingeregionsofconcretebuildingcomponents.Outsideoftheplastichingeregionthestressinthelongitudinal reinforcement bars is not expected to exceed yielding. Hence, themaximumcrackwidthof0.8mmisbasedonstudieswhichhavedemonstratedthatforflexuralmembers(predominantlyframemembers)themaximumcrackwidthatyieldforasectionisapproximately0.8mm(Hoeler,2006;Mahrenholtzetal.,2017).Thecrackwidthswithintheplastichingeregioncanbesignificantlylargerasseismicenergyisdissipatedthroughyieldingofreinforcementandspallingofconcrete.

Concurrently,theUSAhasdevelopedprovisionsfortheprequalificationoffastenersinconcrete.TherequirementsareprovidedinACI355.2(ACI,2007)andACI355.4(ACI, 2011) for mechanical and chemical fasteners in concrete, respectively.Currently, the prequalification requirements are similar to the Europeanrequirementsfornon-seismicapplicationsandC1forseismicperformancecategory.TheUSAisalsointheprocessofintroducingasecondseismicperformancecategorywhichwillbesimilartotheC2categoryinEurope(ICC-ES,2020)

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6. International specification criteria for selection of seismic performance categories

The design specifications for selecting the level of prequalification required forseismic actions varies between international codes and standards. Each nation orregion has provided specifications for selecting seismic performance categoriesbased on their own seismicity, design and construction practice. In general, thecriteriaarebasedononeormoreofthefollowingfactors:seismicdemand,designofthestructure,andconsequenceoffailureofthestructure.ThefollowingsubsectionsprovideasummaryofthespecificationcriteriainEurope,Germany,andtheUSA.

6.1. Eurocode

EN1992-4:2018(CEN,2018)setstheprovisionsforthedesignoffasteningsforuseinconcretestructures,howevereachmemberstatecansettheirownrequirements.The recommended performance categories are provided in Table 2, they aredependenton:thedesigngroundaccelerationonrockgroundconditions(𝑎3),thesoilfactor(𝑆),andthebuildingimportanceclass.

Table2:RecommendedseismicperformancecategoriesforfastenersinaccordancewithEN1992-4:2018

Seismicity ImportanceclassClass 𝒂𝒈𝑺(ing’s) I II III IVVerylow 𝑎.𝑆 ≤ 0.05 NoseismicperformancecategoryrequiredLow 0.05 < 𝑎.𝑆 ≤ 0.1 C1 C11orC22 C11orC22 C2>Low 𝑎.𝑆 > 0.1 C1 C2 C2 C2

1Forconnectingnon-structuralcomponentstostructures|2Forconnectingstructuralcomponentstostructures

6.2. German Annex to Eurocode

In Germany, the specification of the prequalification requirement for fasteners isprovided in the National Annex to EN 1992-4, DIN EN 1992-4/NA:2019-04 (DIN,2019).Theseismicperformancecategoryisspecifiedbasedonthepermissiblecrackwidth of the concrete substrate under seismic load conditions. In addition, it issuggestedthatthebehaviourfactor(𝑞)(i.e.,seismicforcereductionfactortoaccountfor inelastic behaviour) adopted in the design of the structure may be used toestimatethecrackwidthsoutsideoftheplastichingeregionsanddiscontinuityareas.AsummaryoftheminimumrequirementsisprovidedinTable3.

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Table3:MinimumseismicperformancecategoriesrequiredforfastenersinaccordancewithDINEN1992-4/NA:2019-04

Crackwidthunderearthquakedesignload

Prequalificationrequirement Behaviourfactorusedtoestimatecrackwidths

𝑤/ ≤ 0.3𝑚𝑚 Noseismicperformancecategoryrequired

𝑞 = 1.0

𝑤/ ≤ 0.5𝑚𝑚 C1 1.0 < 𝑞 ≤ 1.5𝑤/ ≤ 0.8𝑚𝑚 C2 1.5 < 𝑞 ≤ 3.0𝑤/ > 0.8𝑚𝑚 Fasteningsinplastichingeregions

notcoveredbyDINEN1992-4

𝑤(isthecharacteristiccrackwidth(95percentile)inaccordancewithDINEN1992-1-1andDIN1992-1-1NA

6.3. USA standards

TheUSAseismicdesignprovisionsareprovidedinASCE/SEI7(2016),whichsetstheminimum design loads and associated criteria for buildings and other structures.ACI318M-14 (2019) provides the building code requirements for structuralconcrete, including anchoring into concrete. Seismic design and prequalificationrequirementsarenecessaryforfastenersinstructureswhichareassignedtoSeismicDesign Category (SDC) C, D, E, or F. The assignment of SDC is based on seismicdemandandriskcategoryofthestructure,whereseismicdemandisdefinedbythespectralaccelerationresponseintheshortperiodrangeandatonesecond.TheriskcategoryissimilartotheimportancelevelofbuildingsadoptedintheEuropeanandAustraliancodes.Typically,structuresinAustraliawouldfallwithinSDCofB,CandD.Adirect comparisonbetweenEuropean andUSA recommendations for seismicperformancecategoriesforvariouscitiesinAustraliaisprovidedinLeeetal.(2018).Itisexpectedthatwiththeintroductionofthesecondseismicperformancecategory,theUSAspecificationswillbeextendedtoconsiderthestructuralductilitydemandortoincludeaperformancebasedapproach(ICC-ES,2020).

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PartB

PrequalificationrequirementsanddesignoffastenersinAustralia

7. Specification criteria for selection of seismic performance categories

Under seismic actions, the prequalification requirements of fasteners are highlydependentonthedamagestateoftheconcretesubstratewhichisrelatedtoexpectedcrackwidthsandtheopeningandclosingnatureofthecrack.Therefore,therequiredlevelofprequalificationforthefastenersshallbedeterminedbasedontheexpecteddamageleveloftheconcreteinwhichthefastenersaretobeinstalled.Theminimumseismicperformancecategoryrequiredforfastenersdesignedforseismicactionsasa functionof expected crackwidth isprovided inTable4.Theeffectsofpotentialopeningandclosingofthecrackunderseismicloadingonthefastenershouldalsobeconsideredwhendeterminingasuitablefastenerseismicperformancecategory.

Thespecificationoffastenerperformancecategorybasedoncrackwidthisconsistentwith the specification in the GermanAnnex, DIN EN 1992-4/NA:2019-04 and thecrackwidthrequirementsoftestingproceduresforfastenersinaccordancewiththeEuropeanprequalificationrequirements. Sinceoutsideoftheplastichingeregionsit’sassumedthatthestressandstraininthereinforcementwillnotexceedyield,thecrackwidthsintheseregionsmaybecalculatedbyusingequationswhichhavebeendevelopedforserviceloadconditions.Therefore,itissuggestedthatthecrackwidthsunderseismicactions(outsideofplastichingeregions)maybecalculatedusingtheequationformaximumcrackwidth(𝑤)inaccordancewithAS3600.

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Table4:Minimumrequiredseismicperformancecategoriesforfasteners

Crackwidthunderdesignearthquake Fastenerseismicperformancecategory

𝒘 ≤ 𝟎. 𝟑𝒎𝒎 Seismicprequalificationisnotrequired𝒘 ≤ 𝟎. 𝟓𝒎𝒎 C1𝒘 ≤ 𝟎. 𝟖𝒎𝒎 C2

𝒘 > 𝟎. 𝟖𝒎𝒎(plastichingeregion) Notcovered11Forcrackwidthsgreaterthan0.8mmspecialdesignandalternativesolutionsmayberequired.

A simplified approach is also recommended for selecting seismic performancecategoriesespeciallywhenitisnotfeasibleorpracticaltoconductdetailedanalyses.Thesuggestedcriterion isprovided inTable5and isbasedon:(i) theearthquakehazarddesignfactor(𝑍),(ii)theprobabilityfactor(𝑘-),(iii)thesitesub-soilclass,and(iv)theimportancelevelofthebuilding.TheseparametersshallbedeterminedinaccordancewiththeAustralianearthquakeloadingstandard,AS1170.4andtheAustralianNationalConstructionCode(NCC).

Table5hasbeendevelopedbyconductingarapidseismicassessmentofreinforcedconcrete buildings in Australia. The assessment has approximated the expectedinterstoreydriftdemandoflimited-ductilereinforcedconcretebuildings(typicaltoAustralianbuildingpractice)withtheconsiderationofplanasymmetryandhighermode effects. The recommendations are predominantly based on the flexuralresponseofbuildingcomponentsassumingthatfastenerswillbelocatedoutsideofplastichingeregions.Thesuitabilityoffastenersinshear-controlledcomponentsandinbuildingswithhighlevelofverticalirregularityneedsspecialconsiderationbythedesigner.ThedetailsofthestudyareprovidedinAmirsardarietal.(2020).

Table5:Minimumrecommendedseismicperformancecategoriesforfasteners.

Importancelevel

!𝐤𝐩𝐙$forsitesub-soilclass SeismicperformancecategoryE D C B A

2

Notapplicable

Notapplicable

Notapplicable

≤ 0.1 ≤ 0.12Seismic

prequalificationisnotrequired

Notapplicable 0.08 ≤ 0.12

< 0.1to≤ 0.18

< 0.12to≤ 0.22 C1

≥ 0.08 > 0.08 > 0.12 > 0.18 > 0.22 C2

3Not

applicable0.08 ≤ 0.12 ≤ 0.18 ≤ 0.22 C1

≥ 0.08 > 0.08 > 0.12 > 0.18 > 0.22 C24 ≥ 0.08 C2

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8. Design approach Forthedesignoffastenersunderseismicactions,oneofthefollowingoptionsshallbefulfilled:

Option1-Noductilityrequirement

Fastenersareassumedasnon-ductileelementsanddonotcontributetotheductilebehaviourofthestructure.ThefastenersshouldbedesignedusingeitherOption1aor1b.

(1a) Capacity design: the capacity of non-yielding or yielding fixture orattachedelementdeterminesthemaximumtensionandshearloadimposedontheconnection.Thestrainhardeningandmaterialover-strengthofthefixtureorattachedelementshallbeconsidered.

The fastening shall be designed for themaximum tension and/or shear loadimposed on the connection based on: (i) development of ductile yieldmechanism in the attached element, or (ii) yielding in the baseplate, or (iii)capacityofanon-yieldingstructuralorattachedelementasshowninFigure2.

(1b) Elastic design: elastic behaviour of fastening and structure/element isassumed for the maximum loads obtained from load combinations inaccordance with AS 1170.0 at ultimate limit state (ULS) that includes theearthquake component (Eu). The design forces shall be determined forstructuralconnectionsinaccordancewithAS1170.4with𝑆-/𝜇=1.0andfornon-structuralconnectionsinaccordancewithAS1170.4Section8.

(a)Yieldmechanisminattachedelement

(b)Yieldmechanisminfixture(baseplate)

(c)Capacityofnon-yieldingelement

Figure2:Seismicdesignoffastenerswithoutdamagingfasteners

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Option2-Ductilityrequirement

The fasteners and steel component shall have sufficient elongation capacity to beconsideredasductile.Thisdesignoptionisapplicableforthetensileloadactiononthefastener.Thefastenersorgroupoffastenersisdesignedfortheloadcombinationsincludingearthquakecomponent (Eu)atULS.The tensile capacityof the fasteningrelatedtosteelfailureshallbesmallerthanthetensilecapacityoffastenerrelatedtoconcreterelatedfailuremodes.

It is noted that the fasteners contribution to the energy dissipation in the globalstructural analysis or non-structural element should not be considered unlessappropriatejustificationisprovided,includingnon-lineartimehistoryanalysis.Theprimary structural members could have large non-recoverable displacement offastenersandthisoptionshouldnotbeusedinthesemembers.

Furthermore, for the design of fasteners to satisfy Option 2, following additionalrequirementsshallbemet:

(i) FastenersshallbeprequalifiedforseismicperformancecategoryC2.(ii) Steel failure of the fasteners shall be ensured by satisfying following

requirements:

(A) Forfasteningswithonefastenerintension

𝑅#,.,%& ≤ 0.7𝜙,0.9𝑅#,*/0*,%&

Eq.1

where

𝑅#,.,%& = minimumcharacteristicseismicresistanceforsteelfailurecalculatedinaccordancewithEq.4.

𝑅#,*/0*,%& = minimumdesigncharacteristicseismicresistanceforallconcreterelatedfailuremodes(concretecone,pull-out(mechanicalfasteners),concreteblow-out,concretesplittingandcombinedconeandpull-out(chemicalfasteners))calculatedaccordingtoEq.4.

𝜙,0.9 = capacityreductionfactorforinstallationdeterminedinaccordancewithAppendixA,AS5216,note:𝜙,0.9 =

GH%&'(

.

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(B) Foragroupoffastenerswithtwoormorefastenersintension𝑅#,.,%&𝑆2∗

≤ 0.7𝜙,0.9𝑅#,*/0*,%&

𝑆3∗ Eq.2

where

𝑅#,*/0*,%& = minimumdesigncharacteristicseismicresistanceforallconcreterelatedfailuremodes(concretecone,concreteblow-out,concretesplittingandcombinedconeandpull-out(chemicalfasteners))calculatedinaccordancewithEq.4.

𝑆2∗ = designedloadinthehighestloadedfastenerinthegroup.

𝑆3∗ = designedloadinthegroupoffasteners.

For a group of post-installed mechanical fasteners with two ormore fasteners in tension, the highest loaded fastener shall beverified for pull-out failure in accordance with Eq. 1 where𝑅#,*/0*,%&istheseismicpull-outresistanceofonefastener.

(iii) Allfastenersthataredesignedtotransfertensionloadshallbeductileand have stretch length or elongation ≥ 8𝑑 unless determinedotherwise.

(A) Afastenerisconsideredasductileif𝑓45 ≤ 800 N/mm2,5)*5+*

≤ 0.8

andruptureelongationmeasuredoveralengthof5𝑑is≥12%

where

𝑓65 = yieldtensilestrengthoffastener

𝑓45 = ultimatetensilestrengthoffastener

(B) Thecharacteristicsteelresistanceoffastenerswhichincorporate

areducedsection,suchasthreads,overalengthlessthan8timesthediameteroffastenersatreducedsectionshallbegreaterthan1.3 times characteristic yield resistance of the fasteners at thenon-reducedsection.

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(a)Anchorchair

(b)Sleeveordebondedlength

Figure3:Illustrationofstretchlength

9. Derivation of forces acting on fasteners ThedesignearthquakeforcesactingonthefixtureshallbedeterminedinaccordancewithAS1170.4andSection8.Themaximumvalueoftensionandshearcomponentshall be applied simultaneously when designing the fasteners unless otherwiseprovedbymoreaccurateanalysis.

The distribution of the forces to the individual fasteners of a group shall beundertakeninaccordancewithAS5216(Section4).

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10. Determination of resistance Theseismicdesignresistanceofafastenershallbecalculatedasfollows:

𝑅(,%& = 𝜙,𝑅#,%& Eq.3

where

𝜙, = capacityreductionfactorforstrengthoffastenerorfastenergroupforfailuremodeiinaccordancewithAS5216(Cl3.2.1)

Thecharacteristicseismicresistanceofafastenershallbecalculatedasfollows:

𝑅#,%& = 𝛼3)-𝛼%&𝑅#,%&1 Eq.4

where 𝑅#,%& = characteristicseismicresistanceofafastener.

𝛼3)- = reductionfactortotakeintoaccountforinertiaeffectsduetoanannulargapbetweenfastenerandfixtureincaseofshearloadinganddeterminedinaccordancewithAppendixA,AS5216.

Followingvaluesof𝛼3)-maybeassumediffurtherinformationisnotavailable:

𝛼3)- = 1.0ifnoholeclearancebetweenfastenerandfixture;

𝛼3)- = 0.5ifholeclearancebetweenfastenerandfixtureisinaccordancewithAS5216(Table4.2.2.1).

𝛼%& = factortotakeintoaccounttheinfluenceofseismicactionsandassociatedcrackinganddeterminedinaccordancewithTable6.

𝑅#,%&1 = basiccharacteristicseismicresistanceforagivenfailuremodedeterminedasfollows:

forsteelandpull-outfailureundertensionloadandsteelfailureundershearload,𝑅#,%&1 shallbedeterminedinaccordancewithAppendixA,AS5216(i.e.,𝑁"#,.,%&,𝑁"#,-,%&and𝑉"#,.,%&);

forcombinedpull-outandconcretefailureforchemicalfasteners,𝑅#,%&1 shallbedeterminedaccordingtoAS5216

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(Clause5.2.5,i.e.,𝑁"#,-)usingcharacteristicbondresistance(𝜏"#,%&)inaccordancewithAppendixA,AS5216;

forotherfailuremodes,𝑅#,%&1 shallbedeterminedinaccordancewithAS5216(Chapter6and7,i.e.,fortensionloads:𝑁"#,*,𝑁"#,.-,𝑁"#,*+,𝑁"#,'%,𝑁"#,) = 𝛾*𝑁"(,),andforshearload:𝑉"#,*,𝑉"#,*-,𝑁"#,'%,𝑁"#,) = 𝛾*𝑁"(,)).

The verification of combined tension and shear forces shall be carried out inaccordancewithAS5216 (Clauses8.1.1,8.2.1and8.3.1). Separateverificationshallbecarriedoutforsteelfailureandfailuremodesotherthansteelasfollows:

@𝑁∗

𝜙,𝑁"#,,,%&A#,-

+ @𝑉∗

𝜙,𝑉"#,,,%&A#,-

≤ 1Eq.5

where

𝑁∗ = designtensionforceonthefastenersincludingseismiceffectsforthecorrespondingfailuremodes.

𝑉∗ = designshearforceonthefastenersincludingseismiceffectsforthecorrespondingfailuremodes.

𝑁"#,,,%&𝑉"#,,,%&

= characteristicresistanceoffastenersinseismictensionandshear(Subscriptirepresentsthedifferentfailuremodes).

Followingvaluesshallbeused:

forsteelfailure𝑁"#,.,%&and𝑉"#,.,%&for𝑁"#,,,%&and𝑉"#,,,%&shallbeused,respectively;

forfailuremodesotherthansteelfailure,largestratioof:∗

I%:/0,%,23and @∗

I%@/0,%,23shallbeused.

𝑘GK = factordeterminedinaccordancewithAppendixA,AS5216.Ifdetailedinformationisnotavailablefollowingvaluesmaybeused:

𝑘GK = 1forsteelfailure;

𝑘GK = 0.67forfasteningswithsupplementaryreinforcementtoabsorbshearloadsonly;

𝑘GK = 1inallothercases.

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Table6:Reductionfactor,𝛼01 inaccordancewithEN1992:4(2018)

DesignAction

Failuremode Singlefastener1

Fastenergroup

Tension Steelfailure 1.0 1.0Concretefailure- Undercutfasteners- Allotherfasteners

1.00.85

0.850.75

Pull-outfailure 1.0 0.85Combinedpull-outandconcretefailure(chemicalfastener)

1.0 0.85

Concretesplittingfailure 1.0 0.85Concreteblow-outfailure 1.0 0.85Steelfailureofreinforcement 1.0 1.0Anchoragefailureofreinforcement 0.85 0.75

Shear Steelfailure 1.0 0.85Concretepry-outfailure- Undercutfasteners- Allotherfasteners

1.00.85

0.850.75

Concreteedgefailure 1.0 0.85Steelfailureofreinforcement 1.0 1.0Anchoragefailureofreinforcement 0.85 0.75

1Thisalsoapplieswhereonlyonefastenerinagroupissubjectedtotensionload

11. Displacement requirement of fasteners Forthedesignofastructureorcomponent,alowerlimitstatethantheultimatelimitstate(ULS)maybenecessarytomaintainthefunctionoftheconnectedcomponentsforacertaindesignseismicevent.Thisisreferredtoasdamagelimitstate(DLS)intheprequalificationdocumentinaccordancewithAppendixA,AS5216.

Thedisplacementatthedamagelimitstateundertensionandshearloadsshallbelimited to 𝛿:,'%&(<=>) and 𝛿@,'%&(<=>) to meet necessary requirements, includingfunctionalityandassumedsupport conditions.Thesedisplacementvalues shallbeselected depending upon the requirements of the specific application. If a rigidsupport is assumed in the analysis, the designer shall establish the limitingdisplacementcompatibletotherequirementforthestructuralbehaviour.Itisnotedthat in some cases, the acceptable displacement associated with a rigid supportconditionisconsideredtobeintherangeof3mm.

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Thefastenershallaccommodatethedeformationorrotationrequirementsiftheyarerelevant for the design of the connections (for example, the connection to façadeelementsorstructuralmembersnotpartoftheseismicforceresistingsystem).

Therotationoftheconnectionshallbecalculatedasfollows:

𝜃- =𝛿:,%&𝑠7)8

Eq.6

where

𝜃- = rotationoftheconnection.

𝛿:,%& = displacementofthefastenerunderseismicloading.

𝑠7)8 = distancebetweentheoutermostrowoffastenersandoppositeedgeofthefixtureasshowninFigure4.

Figure4:Illustrationoffasteningdisplacementandrotation

If the fastener displacements under tension and shear loading determined inaccordance with Appendix A, AS 5216 are higher than the correspondingrequiredvalues,theresistanceshallbereducedasfollows:

𝑁"#,%&,'%( = 𝑁"#,%&𝛿:,'%&(<=>)𝛿:,%&(<=>)

Eq.7

𝑉"#,%&,'%( = 𝑉"#,%&𝛿@,'%&(<=>)𝛿@,%&(<=>)

Eq.8

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where

𝑁"#,%&,'%( = reducedcharacteristicseismicresistanceofafasteningundertensionloads.

𝑉"#,%&,'%( = reducedcharacteristicseismicresistanceofafasteningundershearloads.

𝑁"#,%& = characteristicseismicresistanceofafasteningundertensionloads.

𝑉"#,%& = characteristicseismicresistanceofafasteningundershearloads.

𝛿:,'%&(<=>) = requireddisplacementofthefastenerundertensionloadingatDLS.

𝛿:,%&(<=>) = displacementofthefastenerundertensionloadingatDLSdeterminedinaccordancewithAppendixA,AS5216.

𝛿@,'%&(<=>) = requireddisplacementofthefastenerundershearloadingatDLS.

𝛿@,%&(<=>) = displacementofthefastenerundershearloadingatDLSdeterminedinaccordancewithAppendixA,AS5216.

Iffasteningsandattachedelementsarerequiredtobeoperationalafterearthquake,therelevantdisplacementsshallbeconsidered.

12. References ACI (American Concrete Institute). (2007). ACI 355.2-07: Qualification of post-

installedmechanicalfastenersinconcrete.ACIACI (American Concrete Institute). (2011). ACI 355.4-11: Qualification of post-

installedmechanicalfastenersinconcrete.ACIACI(AmericanConcrete Institute). (2019).ACI318:Buildingcoderequirements for

structuralconcrete(ACI318M-19)andcommentary(ACI318RM-19).Michigan:ACI

Amirsardari,A.,Pokharel,T.,Lee,J.,&Gad,E.(2020).Seismicperformancecategoriesfor post-installed fasteners in Australia. Paper presented at the AustralianEarthquakeEngineeringSocietyVirtualConference.

ASCE(AmericanSocietyofCivilEngineers).(2016).ASCE/SEI7-16:Minimumdesignloadsandassociatedcriteriaforbuildingandotherstructures.Virginia:ASCE

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CEN (European Committee for Standardization). (2004). EN 1998-1: Eurocode 8:Designof structures for earthquake resistance -Part1:General rules, seismicactionsandrulesforbuildings.Brussels:CEN

CEN (European Committee for Standardization). (2018). EN 1992-4: Eurocode 2:Designofconcretestructures-Part4:Designoffasteningsforuseinconcrete.Brussels:CEN

DIN (German Institute for Standardization). (2019).DIN EN 1992-4/NA: NationalAnnex - Nationally determined parameters - Eurocode: Deisgn of concretestructures - Part 4: Designing of fastenings for use in concrete, EnglishtranslastionofDINEN1992-4/NA:2019-04.Berlin:BeuthVerlagGmbH

Eligehausen,R.,Mallée,R.,&Silva, J. F. (2006).Anchorage in concrete construction(First ed.). Berlin, Germany: Ernst & Sohn Verlag für Architektur undtechnischeWissenschaftenGmbH&Co.KG.

EOTA(EuropeanOrganisationforTechnicalAssessment).(2016a).EAD330232-00-0601:Mechanicalfastenersforuseinconcrete.

EOTA (European Organisation for Technical Assessment). (2016b). TR 049: Post-installedfastenersinconcreteunderseismicaction.

EOTA(EuropeanOrganisation forTechnicalAssessment). (2017).EAD330499-00-0601:Bondedfastenersforuseinconcrete.

EOTA(EuropeanOrganisation forTechnicalAssessment). (2018).EAD330747-00-0601:Fastenersforuseinconcreteforredundantnon-structuralsystems.

Hoehler, M. S., & Eligehausen, R. (2008). Behaviour and testing of anchors insimulatedseismiccracks.ACIStructuralJournal,105(5),348-357.

Hoeler,M.S.(2006).Behaviorandtestingoffasteningstoconcreteforuseinseismicapplications.(DoctorofPhilosophyThesis).UniversityofStuttgart,Stuttgart,Germany.

ICC-ES (International Code Council Evaluation Service). (2020). AC510-0620-R2:Proposed New Acceptance Criteria for Steel Seismic Qualification of Post-installedAnchorsinConcrete.California,UnitedStatesofAmerica:https://icc-es.org/wp-content/uploads/2020/04/7-AC510-0620-pre.pdf

Lee, J., Pokharel, T., Tsang, H.-H., & Gad, E. F. (2018). Requirement for seismicperformance of post-installed fastenings in Australia. Paper presented at theAustralianStructuralEngineeringConference(ASEC),Adelaide.

Mahrenholtz, P., Wood, R. L., Eligehausen, R., Hutchinson, T. C., & Hoehler, M. S.(2017). Development and validation of European guidelines for seismicqualificationofpost-installedanchors.EngineeringStructures,148,497-508.doi:http://dx.doi.org/10.1016/j.engstruct.2017.06.048

StandardsAustralia.(2007).AS1170.4-2007(R2018):Structuraldesignactions-Part4:EarthquakeactionsinAustralia.Sydney:SAIGlobal

StandardsAustralia.(2018).AS5216:Designofpost-installedandcast-infasteningsinconcrete.Sydney:SAIGlobal

www.aefac.org.au

Disclaimer: The information provided in this Technical Note is intended forgeneralguidanceonly,andinnowayreplacestheservicesofdesignengineersonparticular projects or subjects. AEFAC and its board, constituent members,representativesoragentswillnotbeliableforanyclaimsordamageswhatsoeverresultingfromuseorrelianceoninformationinthisTechnicalNote.

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