ACI 318-08, Appendix DACI 318-08, Appendix D

IBC 2006 Section 1912IBC 2006 Section 1912

Anchorage to ConcreteAnchorage to Concrete

Mark Bartlett, PEMark Bartlett, PE

Field Engineer Field Engineer 

Simpson Anchor SystemsSimpson Anchor Systems

Presentation TopicsPresentation Topics

•• BBrriieef f HHiissttoorry y oof f AAnncchhoor r DDeessigignn

•• AACCI I 331188--0088, , AAppppeennddiix Dx D•• DDeessiiggn n EEqquuaattiioonnss

•• PPhhi i ((ФФ) Factors) Factors

•• IInntteerraaccttiioon n EEqquuaattiioonn

•• SSeeiissmmiic c PPrroovviissiioonnss

•• ReReininfoforcrceemmenent to Pt to Prerevevent Bnt Brereaakokoutut

•• OOtthheer r IIssssuueess

•• EdEdge ge DiDiststananceces, s, ThThicicknknesesseses & s & SpSpacaciningsgs

•• WWhheen n tto o ddeessiiggn n ppeer r AApppp. . DD

•• IIBBC C 22000066

•• AAddhheessiivve e AAnncchhoorrs s aannd d CCoonnccrreetteeScrewsScrews

•• TThhe e FFuuttuurre e oof f AAnncchhoor r DDeessiiggnn

Prior to ACI 318-02Prior to ACI 318-02

•• CasCast-It-In-Pn-Placlace ance anchohors cors coververed byed by::

 – – PCI / ACI 349PCI / ACI 349

 – – UBC / IBC codes listed allowableUBC / IBC codes listed allowable

stressstress capacitcapacities foies for CIr CIP boltP boltss

Prior to ACI 318-02Prior to ACI 318-02

•• DesDesigign of Pon of Post-st-InsInstaltalleled ancd anchorhors:s:

 – – Individual manufacturers suppliedIndividual manufacturers suppliedload values based on testingload values based on testing

 – – Values found in catalogs andValues found in catalogs andICBO/ICC reportsICBO/ICC reports

 – – Methodology was allowable stressMethodology was allowable stressand asand assumesumed an uncrd an uncrackeackedd andandunrunreineinforforcedced sectsectionion..

ACI 318-08, Appendix DACI 318-08, Appendix D

ACI 318, Appendix DACI 318, Appendix D

•• StStrerengngth th dedesisigngn memeththod od fofor r anchorage to concreteanchorage to concrete(i.e. N(i.e. Nuaua ≤ ≤ ΦΦNNnn oror VVuaua ≤ ≤ ΦΦVVnn)) – – Cast-In-Place (CIP) anchorsCast-In-Place (CIP) anchors

 – – Post-Installed (PI) anchorsPost-Installed (PI) anchors•• UndUndercercut ut ancanchorhorss

•• TorqTorque-coue-controntrolled lled anchoanchorsrs

•• DefoDeformatrmation-cion-controontrolled lled anchoanchorsrs

 – – PI anchors must be prequalifiedPI anchors must be prequalified per per ACI 355.2ACI 355.2

Appendix D Design Equations & Appendix D Design Equations & FailureFailure

ModesModes

•• DeDesisign egn eququatatioions cns cheheck 5ck 5different failure modesdifferent failure modes – – Steel capacitySteel capacity

•• TeTensnsioion ann and Shd Sheaear r 

 – – Concrete breakout capConcrete breakout capacityacity•• TeTensnsioion ann and Shd Sheaear r 

 – – Pullout/Pull-through capacityPullout/Pull-through capacity•• TeTensnsioion on onlnlyy

 – – Concrete PryoutConcrete Pryout•• SSheheaar or onlnlyy

 – – Concrete side-face blowoutConcrete side-face blowout•• TenTensiosion an and nd CIP CIP onlonly.y.

Appendix D Design EquationsAppendix D Design Equations

Design EquationsDesign Equations

Tension CapacitiesTension Capacities

NNsasa = nA= nAse,Nse,Nf f utauta

NNcbcb = A= ANcNc/A/ANcoNco((ΨΨec,Nec,NΨΨed,Ned,NΨΨc,Nc,NΨΨcp,Ncp,NNNbb))

NNpnpn == ΨΨc,Pc,PNNpp

NNsbsb = (160c= (160ca1a1√√AAbrgbrg))λ√λ√f’f’cc

Shear CapacitiesShear CapacitiesVVsasa = n 0.6 A= n 0.6 Ase,Vse,V f f utauta

VVcbgcbg = A= AVcVc/A/AVcoVco((ΨΨec,Vec,VΨΨed,Ved,VΨΨc,Vc,VΨΨh,Vh,VVVbb))

VVcpgcpg = k= kcpcpNNcbgcbg

Steel Strength in TensionSteel Strength in Tension

SteeSteel Strel Strength In Tength In Tensionsion –n – D.5.D.5.11

NNsasa = nA= nAse,Nse,Nf f utauta(Eq. D-3)(Eq. D-3)

 – – NNsasa – – Nominal tensileNominal tensilestrength of an anchor groupstrength of an anchor group

 – – n –n – Number of anchorsNumber of anchors

 – – AAse,Nse,N – – Effective crossEffective crosssectional area of anchor insectional area of anchor intensiontension

 – – f f utauta – – Specific ultimate tensileSpecific ultimate tensilestrength of anchor strength of anchor 

Concrete Breakout StrengthConcrete Breakout Strength

in Tensionin Tension

ConcConcrete Brrete Breakoueakout In Tensit In Tension –on – D.5.D.5.22

NNcbcb=A=ANcNc/A/ANcoNco((ΨΨec,Nec,NΨΨed,Ned,NΨΨc,Nc,NΨΨcp,Ncp,NNNbb))(Eq. D-5)(Eq. D-5)

•• NNcbcb – – Concrete breakout strength inConcrete breakout strength in

tensiontension

ConcConcrete Brrete Breakoueakout In Tensit In Tension –on – D.5.D.5.22

NNcbcb==AANcNc/A/ANcoNco((ΨΨec,Nec,NΨΨed,Ned,NΨΨc,Nc,NΨΨcp,Ncp,NNNbb))

•• AANcNc – – Projected failure area of groupProjected failure area of group

•• AANcoNco = 9 h= 9 hef ef 22 Projected failure area of Projected failure area of 

one anchor one anchor  (Eq. D-6)(Eq. D-6)

ConcConcrete Brrete Breakoueakout In Tensit In Tension –on – D.5.D.5.22

NNcbcb=A=ANcNc/A/ANcoNco((ΨΨec,Nec,NΨΨed,Ned,NΨΨc,Nc,NΨΨcp,Ncp,NNNbb))

Modification for eccentric loadModification for eccentric load

ΨΨec,Nec,N = 1/[1+(2e’= 1/[1+(2e’NN/3h/3hef ef )])] (Eq. D-9)(Eq. D-9)

TT33 TT22 TT11

NN

Resultant tension loadResultant tension load

e’e’NN

CentCentroidroid of of 

anchorsanchors

ConcConcrete Brrete Breakoueakout In Tensit In Tension –on – D.5.D.5.22

NNcbcb=A=ANcNc/A/ANcoNco((ΨΨec,Nec,NΨΨed,Ned,NΨΨc,Nc,NΨΨcp,Ncp,NNNbb))

Modification for edge effectsModification for edge effects

If cIf ca,mina,min >> 11..55hhef ef  then:then:

Eq. D-10Eq. D-10 ΨΨed,Ned,N = 1.0= 1.0

If cIf ca,mina,min < 1.5h< 1.5hef ef  then:then:

Eq. D-11Eq. D-11 ΨΨed,Ned,N = 0.7 + 0.3 (c= 0.7 + 0.3 (ca,mina,min / 1.5h/ 1.5hef ef ))

ccaa

ConcConcrete Brrete Breakoueakout In Tensit In Tension –on – D.5.D.5.22

NNcbcb=A=ANcNc/A/ANcoNco((ΨΨec,Nec,NΨΨed,Ned,NΨΨc,Nc,NΨΨcp,Ncp,NNNbb))

Modification for crackingModification for cracking

ΨΨc,Nc,N =1.=1.4 for uncr4 for uncrackeackedd sectsection if ion if 

kkcc = 17 in eq. (D-7)= 17 in eq. (D-7)

ΨΨc,Nc,N per evaluation report (ER) if kper evaluation report (ER) if kcc

from ER used in eq. (D-7)from ER used in eq. (D-7)

ΨΨc,Nc,N =1.0 for cracked section=1.0 for cracked section

ConcConcrete Brrete Breakoueakout In Tensit In Tension –on – D.5.D.5.22

NNcbcb=A=ANcNc/A/ANcoNco((ΨΨec,Nec,NΨΨed,Ned,NΨΨc,Nc,NΨΨcp,Ncp,NNNbb))

ΨΨcp,Ncp,N – – Modification for Post-InstalledModification for Post-Installed

anchorsanchors

UncUncracrackedked conconcrecretete

No supplemental reinf. to control splittingNo supplemental reinf. to control splitting

If cIf ca,mina,min >> ccacac then:then:

ΨΨcp,Ncp,N = 1.0= 1.0 (Eq. D-12)(Eq. D-12)

If cIf ca,mina,min < c< cacac then:then:

ΨΨcp,Ncp,N = c= ca,mina,min/c/cacac (Eq. D-13)(Eq. D-13)

Where cWhere cacac= 2.5 h= 2.5 hef ef (undercut anchors)(undercut anchors)

4 h4 hef ef (wedge anchors)(wedge anchors)

ConcConcrete Brrete Breakoueakout In Tensit In Tension –on – D.5.D.5.22

NNcbgcbg=A=ANcNc/A/ANcoNco((ΨΨec,Nec,NΨΨed,Ned,NΨΨc,Nc,NΨΨcp,Ncp,NNNbb))

•• BaBasic csic conconcrerete brte breaeakokout stut strerengngthth

•• NNbb=k=kcc λλ f’f’cc hhef ef 1.51.5 (Eq. D-7)(Eq. D-7)

 – – kkcc – – Coefficient for basic concreCoefficient for basic concretetebreakout strengthbreakout strength

•• Found Found in eiin either Apther App. D op. D or per r per prodproduct ERuct ER

 – – λλ – – Modification factor for lightweighModification factor for lightweighttconcreteconcrete

 – – f’f’cc – – Concrete comprConcrete compressive strengthessive strength

 – – hhef ef  – – Effective embedmEffective embedment depthent depth•• TeTesstteed d hhef ef  found in manufacturer’s catalog or found in manufacturer’s catalog or 

product ERproduct ER

Pullout Pullout Strength Strength in in TensionTension