SITE TESTING GUIDELINES VOL 4: TESTING IN MASONRY

Ver.1.1January2020

TECHNICAL NOTE

AEFAC-TN05

www.aefac.org.au

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TECHNICAL NOTE: SITE TESTING GUIDELINES – VOL 4: TESTING IN MASONRY

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Scope ThisTechnicalNote isVolume4of a suite ofAEFAC technicalNotesdedicated toprovidingrecommendationsforbestpracticeforthesitetestingoffasteners.Volume4providesguidancespecifictotestsonfastenersinstalledinmasonrysubstrates.

Therecommendationsareintendedtoassistdesignengineersformulateappropriatesitetestingprocedures,andtoassistfieldtestersconductingtestsonsite.

ThescopeofVolume4providesrecommendationsspecifictotestinginmasonrythataresupplementarytotherecommendationsprovidedinVolumes1–3([1],[2],[3]).ItisarequirementthatVolume4beusedinconjunctionwithVolume1[1].

It isassumedthatsitetestsaretobeperformedonchemicalfastenersinmasonrythat have been tested and assessed in accordance with EAD 330076 [4]. Forprocedures regarding the site testingofmechanical fasteners the engineer shouldseekadvicefromtheproductmanufacturer’stechnicalsupportservice.

Thisdocumentprovidestechnicaladviceonsitetestingtechniquestodeterminethestrength of fasteners and does not address all safety precautions needing to befollowedduringsitetestingoffasteningstoconcrete.

Notation AfulllistofnotationsisprovidedinSection2ofVolume1.

Terminology AfulllistofterminologyislistedinSection3ofVolume1.

General It is an underlying assumption of this Technical Note that the fastener has beenapproved–eitherthroughanETAoraprovisionalapprovalbythemanufacturer–foruseinthetypeofmasonryunderconsiderationincluding–

i) characteristics of the unit: material (concrete/AAC/clay) and geometry(solid/hollow/perforatedanddimensions),and

ii) characteristicsofthemortar:materialcompositionanddimensionsThe locationof fasteners inmasonry ingeneral shouldbe situatedaway from thecomparativelyweakerjointsandedgeofmasonry.ComprehensiveguidanceongoodpracticeforthepositioningoffastenersinmasonryispublishedinBS8539:2012[5].

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ThescopeofEAD330076[4]includesinjection fasteners consisting of a threaded rod, deformed reinforced bar, internal threaded socket, or other shapes and the mortar, placed into drilled holes in masonry and anchored by bonding the metal part to the sides of the drilled hole by means of mortar and by mechanical interlock. Masonry units included under this prequalification include clay, calcium silicate, normal weight concrete and lightweight concrete (solid and hollow or perforated format blocks), autoclaved aerated concrete, and other similar materials. Injection fastener units for use in hollow masonry typically employ a sieve to promote mechanical interlock as illustrated in Figure1.

Note: The fastener should be suitably prequalified for use in the type of masonry (solid/hollow/perforated).

Figure1:Injectionfastenerinhollowmasonryemployingasieve.

EAD 330076 [4] covers the testing and assessment of injection fasteners for use in masonry. If an injection product for use in masonry is awarded an ETA and has been specified for use in a project, testing on site is not required provided all aspects of the application (e.g. injection fastener, type and strength of bricks and mortar, geometry of masonry, installation practice) conform to the requirements of the ETA. If the base material contains different bricks to those in the ETA that are of the same type (e.g. perforated), then job site tests may be conducted to establish the characteristic strength.

AlthoughthescopeofthisTechnicalNoteisrestrictedtochemicalfasteners,othertypesof fastenerssuchasshield fastenersandstud fastenersmayalsobeused inmasonry[6].

AEFACTechnicalNote09[10]providesinformationonselectionandinstallationofpost-installedfastenersinmasonry.

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Tests to determine suitability of fastener

5.1. Simplified tests

Simplified tests may be performed to a test load (Ntest) and an estimation ofcharacteristicstrengthofthefasteningmaybemade.GeneralguidanceonthenatureofasimplifiedtestisprovidedintheAEFACTechnicalNotes“SiteTesting–Vol.1:General”[1]and“SiteTesting–Vol.2:ProofTest”[2].

5.2. Ultimate tests

Ultimate tests may be performed to establish a more accurate estimation of thecharacteristicstrengthofthefastening.IfthefastenerisbeinginstalledinmasonryandhasbeenawardedanETAapplicabletomasonry,ultimatetestsarenotrequiredifthetypeofsubstrateanddimensionsofthemasonryconformtotheETA.However,ifthecharacteristicsofthesubstratevarythenultimatetestsarerequiredtoestablishthecharacteristicstrength.

Theproceduretofollowforthedeterminationoftheultimatestrengthofachemicalfastenerinmasonrydependsonthenatureoftheprequalification.Figure2illustratesthedifferentpathsthatmaybefollowedinordertoestablishtheultimatestrengthofafastenerinmasonry.

Allowablestrengthoffastenerinmasonry

ETAawardedfromEAD330076foruseinmasonry

NoETA,manufacturer’sprovisionalapprovalforuseinbasematerial

Simplified(conservative)approachwherebya

nominatedtestloadisappliedto

establishallowablestrength

Statisticalapproachbasedoncarefullytestinga

numberoffastenerstofailure

toestablishallowablestrength

Allowablestrength

calculatedfrommeanvalueofthe

5smallestmeasuredvalues

fromtests(>15ultimate

tests)

Allowablestrengthbasedon5%fractileofmeanultimateloadmeasuredfromtests

(5–15ultimatetests)

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Figure2:Pathstoestablishingallowablestrengthoffastenerinbasematerial.

There are a number of avenues that may be followed in order to determine theultimatestrengthofafastenerinagivenbasematerial.Thefactorsinfluencingthecalculationofstrengthincludefastenerprequalification,natureofthebasematerial,numberofteststhathavebeenconducted,andwhetherornotthebasematerialmaybedamagedfromtestingtofailure.

Thefollowingsectionsoutlinetheprocedureforcalculatingtheallowablestrengthofafastenerinabasematerialdependingonproductprequalification,andthenatureandnumberoftestsconducted.

Additional guidance ultimate testing is provided in AEFAC Technical Notes “SiteTesting–Vol.1:General”[1]and“SiteTestingVol.3:Ultimatetests”[3].

Note:Sitetestingguidelinesprovided inEOTATR053notetheuseof“prooftests”tocalculate the characteristic strength of the chemical fastener inmasonry. The term“prooftest”intheAEFACSiteTestingGuidelinesTechnicalNotesisreservedexclusivelyfortheverificationoffastenerinstallation.

Test setup The general requirements for the test equipment and configuration for testing inmasonryareprovidedinAEFACTechnicalNote“Sitetesting–Vol.1:General”[1].SpecificguidanceonprooftestsandultimatetestsareprovidedinAEFACTechnicalNotes“Sitetesting–Vol.2:Prooftests”[2]and“Sitetesting–Vol.3:Ultimatetests”[3],respectively.

Giventherelativelyweaknatureofmortarjointsinmasonryitisimportantthatthetest rig legs are supportedbydifferent units than the one including the fasteningunderinvestigation.Thistestsetupwillensurethebrickbreak-outfailuremodeisnotinhibitedbytheplacementofthetestrigsupports.

Test regime

7.1. Application of load

7.1.1. Simplified method

Asaguide,thetestload(Ntest)maybeestimatedbasedonthefollowing:

Ntest > (1)

where bfM

S *8.0

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S* = Designload(characteristicactionappliedtothefastener×loadfactori.e.factoredappliedload)

ϕM = capacityreductionfactorformasonry = 1/γM

γM = partialsafetyfactorformasonry(publishedinETA) = 2.5wherenofurtherguidanceisavailable β = factor considering influences of product – determined from

prequalification(publishedinETA)

7.1.2. Statistical method

TheloadistobeincreasedinaccordancewiththerequirementsofVol.3[3],Cl.7.1.

7.2. Test sequence

DetailsofthetestsequenceareprovidedinAEFACTechnicalNote“Sitetesting–Vol.1:General”[1].

7.3. Number of tests

The requirements for job site tests are outline in EOTA TR053 [7]. In order toestablish the characteristic strength (5% fractile), at least 15 tests need to beperformed. If fewer than 15 tests are conducted a statistical estimation ofcharacteristicstrengthisdetermined,includinganadjustmentβ-factorsourcedfromtheprequalificationdocument(e.g.ETA).Partialsafetyfactorsapplicabletomasonrysubstratearealsoprovidedfortheevaluationoftests.

Although there are guidelines for the minimum required number of tests to beperformed,therequirementsforeachprojectshouldbeconsideredonthebasisofthe fixing requirements. Projectswith complex installation requirements ormorevariablesubstrateforinstance,mayrequireagreaternumberofteststoachievethedesiredconfidenceinthefixingsystem.

7.4. Modes of failure

EOTATR054[8]outlinesthedesignprocedureforthefixturefortheultimatelimitstatebasedonaninjectionfastenerprequalifiedinaccordancewithEAD330076[4],addressingpotentialfailuremodesoccurringundertensileorshearloadingoutlinedinTable1.

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TheEOTAdocuments([4],[7],[8])andalistofinjectproductsforuseinmasonryawardedETAsmaybefoundontheEuropeanOrganisationforTechnicalAssessment(EOTA)website(www.eota.eu).

Note:SomepotentialmasonryfailuremodesdiffertothoseinconcreteidentifiedinAS5216:2018[9].

Table1:Potentialmodesoffailureoffastenerinmasonryundertensileorshearloading.

Modeoffailureundertensileloading Modeoffailureundershearloading

• Metalfracture • Failureofmetalpartwithoutleverarm

• Pull-outfailureoffastener • Failureofmetalpartwithleverarm

• Brickbreakoutfailure • Localbrickfailure

• Pull-outofonebrick • Brickedgefailure

• Influenceofjoints • Pushingoutofonebrick

• Influenceofjoints

Evaluation of results of tests

8.1. Simplified tests

Using the results of the simplified tests an estimate of the characteristic strength(NRk,2) of themasonrymay bemade as follows, provided no visiblemovement ordisplacementoftheinjectionfastenersoccurinalltests:

NRk2 = <NRk,ETA (2)

where Ntest = testload

β = product-dependentinfluencingfactor

NRk,ETA = characteristic strength determined through prequalification andpublishedintheETA

The following simplifications may be made when estimating characteristic shearstrength:

i) IfVRk,ETA>NRk,ETA,VRk2=NRk2<VRk,ETAii) IfVRk,ETA<NRk,ETA,VRk2=NRk2(VRK,ETA/NRk,ETA)<VRk,ETA

8.0btestN

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8.2. Statistical tests

8.2.1. Anchors having an ETA

This evaluation isonlyapplicablewhena fastenerhasbeenawardedanETA thatcoverstheintendedsubstrate(refertoSection4).

8.2.2. Characteristic strength for less than 15 tests

Where less than 15 ultimate site tests are performed, the characteristic strength(NRk1)isdeterminedinaccordancewithEquation(3)asfollows:

NRk1 = NRu,m(1-ks.v)β < NRk,ETA (3)

where NRk1 = characteristicultimatestrengthdeterminedfromtests

NRu,m = meanultimateloadcalculatedfromtestresults ks = samplefactorfromTable2 v = coefficientofvariationofultimateloadscalculatedfrom

testresults

= s/NRu,m s = standarddeviationofultimateloadscalculatedfromtest

results

β = influencingfactorprovidedintheapprovaldocumentforfastenersin masonry applications (ETA awarded in accordance with EAD330076[4])

NRk,ETA = characteristic strength published in the approvaldocument

Note:Thisprocedureassumes the fastenerhasbeenprequalified inaccordancewithEAD330076.

8.2.3. Characteristic strength for a minimum of 15 tests

Intheeventthatatleast15ultimatetestsareconductedonsite,thecharacteristicstrength(NRk1)isdeterminedinaccordancewithEquation(4):

NRk1 = 0.5N1<NRk,ETA (4)where

NRk1 = characteristicultimatestrengthdeterminedfromtests N1 = mean value of the five smallest measured ultimate

strengths

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NRk,ETA = characteristicstrengthNRkgivenintheETAforthesamecategoryofmasonry

Forshearstrength:

i) IfVRk,ETA>NRk,ETA,VRk1=NRk1<VRk,ETAii) IfVRk,ETA<NRk,ETA,VRk1=NRk1(VRK,ETA/NRk,ETA)<VRk,ETA

8.2.4. Design strength

Thedesignstrengthofthefastener(NRd)maybedeterminedaccordingwithEquation(5):

NRd = φMNRk1 (5)where

NRd = designstrengthofthefastener

φM = capacityfactorformaterial

= 1/γM, where the partial safety factor formaterial strength (γM) isobtainedfromtheapprovaldocument(e.g.ETA).IntheabsenceoffurtherguidanceitmaybeassumedthatγM=2.5.

NRk1 = characteristicultimatestrengthdeterminedfromtests

Note:AnETAincludespartialsafetyfactorstoaccountforuncertainties,whereastheseuncertainties are accounted for in Australian design standards via capacity factors.FurtherguidanceisprovidedintheAEFACTechnicalNote“Designconceptsforpost-installedandcast-infasteners”[7]andAEFACTechnicalNote“Prequalificationofpost-installedandcast-infasteners”[8].

Table2:Samplingfactorforthe5%fractileofstrengthwitha90%confidenceinterval.

No.tests ks No.tests ks No.tests ks

5 3.400 10 2.568 40 2.010

6 3.091 15 2.329 50 1.965

7 2.894 20 2.208 ∞ 1.645

8 2.755 25 2.132

9 2.649 30 2.080

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NOTE:Thegreaterthenumberoftests,thegreatertheconfidenceintheresultsandthelowerthestatisticalpenaltyinthedeterminationofcharacteristicstrength,representedbyalowerks-value.

Additional requirements for tests FurtherconsiderationsrequiredpriortotestinginmasonryareprovidedinAEFACTechnicalNote“Sitetesting–Vol.1:General”[1].

Report of results SuggestedinformationtobeincludedinthereportgeneratedfromsitetestingmaybefoundinAEFACTechnicalNote“Sitetesting–Vol.1:General”AppendixA[1].

Summary Volume4ofthesuiteofsitetestingTechnicalNotesprovidesguidanceforthetestingoffastenersinmasonry.Theproceduretobefolloweddependsonthenatureofthefastener’sprequalificationandtheobjectiveofthetest(proofloadorultimatetest).Certaintypesoffastenersdonotfunctioncorrectlyinmasonrysoitisimperativethefastenerhasasaminimum,aprovisionalapprovalgrantedbythemanufacturerforuseinmasonry.

References [1] “Site Testing Guidelines – Vol 1: General”, AEFAC Technical Note 05,

www.aefac.org.au [2] “Site Testing Guidelines – Vol 2: Proof tests”, AEFAC Technical Note 05,

www.aefac.org.au

[3] “Site Testing Guidelines – Vol 3: Ultimate tests”, AEFAC Technical Note 05,www.aefac.org.au

[4] EAD 330076 “Metal injection anchors for use in masonry”, EuropeanOrganisationforTechnicalAssessment,2017,www.eota.eu

[5] BritishStandard8539:2012,“Codeofpracticefortheselectionandinstallationofpost-installedanchorsinconcreteandmasonry”,BSIStandardsLimited

[6] “Fixings for brickwork”, Article, Construction Fixings Association, www.the-cfa.co.uk

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[7] EOTATR053“Recommendationsforjob-sitetestsofmetalinjectionanchorsforuse in masonry”, European Organisation for Technical Assessment, 2016,www.eota.eu

[8] EOTATR054“Designmethodsforanchorageswithmetalinjectionanchorsforuse in masonry”, European Organisation for Technical Assessment, 2016,www.eota.eu

[9] AS 5216:2018 “Design of post-installed and cast-in fastenings in concrete”,StandardsAustralia

[10] “SelectionandInstallationoffastenersinMasonry”,AEFACTechnicalNote09,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.

www.aefac.org.au