00 ASCE b Bachman

8/13/2019 00 ASCE b Bachman

1/78

SeismicDesignRequirementsfor

ons ruc ura omponen s

, . ., . .,

ChairASCE702andASCE705

ASCE7SeismicSubcommittee

ViceChairofASCE710MainCommittee

2011MCEERSeminarJune9,2011 1


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WhatareNonstructuralComponents?

NonstructuralComponentsisthecommonnamegivetothoseitemsinastructurethatarenotpartofthestructuralsystem.Theyinclude:

Architecturalcomponentsincluding:cladding,ceilings,glazing,curtainwalls,

partitionsand

finishes,

raised

computer

floors,

etc.

Mechanicalandelectricalcomponentsandsystems(utilities)including:tanks,pipingandvessels.

, , ,shelvesandbookcases,valuablecontentsonshelves,etc.

Nonstructuralcomponentsincludetheanchorageandattachmentsthatconnectthe

June9,2011 22011MCEERSeminar

.


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Definitionofcomponent,supportandattachment


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attachment

component

support

2010 John F. Silva



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HistoricalPerformance

Damage/FailureofNonstructuralComponentsindeveloped

Typicallyresultsinthemajorityofearthquakefinanciallosses

Lossesinanindividualstructurecanexceed50%ofthetotal valueofastructureeventhoughthestructureitselfsustains littleornodamageespeciallywhenconsideringdowntime

Havecausedinjuriesandfatalities

Havecausedessentialfacilitiestobecomenonfunctional



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NorthridgeEarthquake


OSHPD/FDD


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Northridge Earthquake


OSHPD/FDD


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NorthridgeEarthquake


OSHPD/FDD


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Northridge Earthquake

Chiller

equipment and

piping move out ofp ase ur ng an

earthquake and the

case shells are not

designed to resistthe force necessary

June9,2011 102011MCEERSeminarOSHPD/FDD


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overturnedhospitalimagingequipment


2009 NEHRP Recommended Seismic Provisions for New Buildings and Other Structures


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overturnedcabinets,hospitalward




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F

h

OriginaldesignFp:0.55g

A307boltcapacity(elastic):

0.19g

Ultimate:0.27g

Probableacceleration:0.84g

(JohnA.

Blume

report

to

OSHPD1994

s

Neq

Degenkolb Engineers

Overturnedliquidoxygentank,Olive

ViewHospital


Northridge1994

Degenkolb Engineers


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June9,2011 142011MCEERSeminarnonstructuraldamagetoCourtofAppealsbuilding Talca,Chile

. . ac man . . ac man


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U.S.BuildingCodeSeismicRequirements

ASCE-7

MinimumDesign Loads

for Buildings

and Other

Structures

Design

Specification

Load

&

ResistanceFactor

Design

Building Code



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WhoDevelopedtheNonstructuralSeismic

TheNonstructuralSeismicRequirementsare

primarilybasedontheNEHRPRecommended

SeismicProvisions

for

Buildings

and

Other

Structures

ec n ca omm ee

ThechangestoASCE705foundinASCE710were

ASCE7SeismicSubcommittee(SSC)



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NEHRPProvisionsATC 3.06

1997 EDITION 1997 EDITION

Tentative

Recommended

Provisions for

NEHRP RECOMMENDED PROVISIONS

FOR SEISMIC REGULATIONS

FOR NEW BUILDINGSAND OTHER STRUCTURES

NEHRP RECOMMENDED PROVISIONSFOR SEISMIC REGULATIONS

FOR NEW BUILDINGS

AND OTHER STRUCTURES

of Buildings

PART 1 - PROVISIONS PART 2 - COMMENTARY

FirstpublishedbyBSSCin1985

Wasupdatedon3yearcycle(1988,91,94,97,00,03)

1992 AdoptedbyBOCA,SBCCI

1993 AdoptedbyASCE7forSeismic


reso ves oa op as as s or

2009 AdoptedASCE705asReferenceBasis


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BackgroundontheDevelopmentProcess

PrimaryseismicrequirementsfoundinASCE710arebased, .

AbigchangeinthepresentationofseismicrequirementsinASCE 705. The seismic re uirements were reor anized as 13chaptersinsteadof1chapter.

TheSeismicRequirementsforNonstructuralComponents

werelocatedinChapter13

The2009NEHRPRecommendProvisionsincludesagreat


.


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OverviewofASCE705

Seismic Re uirements for Nonstructural Com onents

TohelpbetterexplainthechangesbetweenASCE705and

ASCE710..Anoverviewo wi irst eprovi e regar ingt e

seismicrequirementsforNonstructuralComponentsfoundin

Chapter13ofASCE705.



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PerformanceExpectationsfor

Intensit of round motionPerformance expectation

p=

Minor not defined

Minimal damage,

functionalit im airmentunlikely

Some damage, functionality

potentially impacted

Major damage, significant


es gn ar qua e e ne a ng azar s m ga e ,

functionality loss likely


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NEHRPRecommendProvisions/ASCE7

Toavoidseriousinjuryorlossoflife

Toavoidlossoffunctionofcriticalfacilities(Ip=1.5)

Tominimizerepaircoststotheextentpractical

Nonstructuralcomponentrequirementsandperformance

expectationsareonlytiedtheDesignEarthquake.

Thereare

no

performance

expectations

for

Nonstructural

ComponentsthataretiedtotheMaximumConsidered


.


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KeyFactorsinSeismicDesign

MappedGroundMotionsSsandS1 SiteClassificationA F

SiteResponseCoefficientsFaandFvFaNonlinearfunctionof Ss andSiteClass

FvNonlinearfunctionof S1 andSiteClass

SDS= 2/3FaSsS = 2 3F S



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OtherKeyFactors

Occu anc Cate or I to IV and

ImportanceFactor,IE 1.0to1.5

. .

Lowhazard I 1.0

.

Important III 1.25


.


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RiskCategoryversusOccupancyCategory

ASCE710,thetermRiskCategoryisusedinsteadoftheterm

OccupancyCategory utt eimp ementationo owt eyare

usedforseismicdesignisstillthesame.

ThereisprovidedaconversionstatementinASCE7onhow

oneconvertsOccupancyCategorytoRiskCategory.

FromaChapter13perspective,ithasnoeffect.



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NonstructuralImportanceFactorIp

ons ruc ura omponen mpor ance ac or, p,ass gne oa

components ThevaluesofIpiseither1.0or1.5

ThevalueofIpisbasedon:

1.

Requirementsof

the

component

to

function

after

a

DBE

suc asspr n ersys ems ,or

2. Thecomponentcontainshazardousmaterials,or

3. StorageRacksopentogeneralpublic, or

.

ccupancy

ategory

o

t e

structure

or

ac ty

essent a Nonstructuralcomponents/systemswhichareassignedanIp =1.5are

calledDesignatedSeismicSystems.



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SeismicDesignCategory

SeismicDesignCategoriesAF

DesignGroundMotionValues SDSandSD1

10)

*

exemptions



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NonstructuralLimitsofApplicability

NonstructuralprovisionsapplythroughouttheUSwith

followingexceptions:

.

SDCAandB

2. MechanicalandElectricalinSDCifI =1.03. ArchitecturalinSDCA

4. ArchitecturalinSDCBifIp=1.0exceptfor

Otherexceptionsforlightitems,pipingandductworkinboth



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SeismicDesignCategoriesforSiteClassD OccupancyCatII

SDCA=White,SDCB=Green,SDCC=Yellow,SDCD/E=Red



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NonstructuralSeismicDemands

EquivalentStaticForcesFpEquations Simplestisindependentofbuildingstructuralproperties

1. StrengthLevelForces

2. ASCE705providesoptionfordeterminingbuildingspecific

forces

RelativeDisplacementsforSelectedComponents

1. AnticipatedRelativeDisplacementsatDesign

p

2. Providesexplicitequationsandoptionofdeterminingdemandsusingbuildingstructuralproperties



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ons ruc ura orce emanSimple Equation

ASCE705 Base on1997NEHRP

F = 0.4 a SDS ( 1 + 2 z ) W (Eq. 13.3-1)(Rp / Ip ) h

F min = 0.3 S I W orS =

1.00

F =

0.30

I W

Fp (max) = 1.6 SDS Ip Wp forSDS=1.00,Fp=1.60IpWp

where:

z/h=relativeheightratioofcomponentattachmentpointSDS=shortperioddesignearthquakegroundmotioncoefficient

ap=componentdynamicamplificationfactor


Rp=componentresponsemodificationfactor

Ip =component

importance

factor


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Nonstructural Force DemandComplex Equation Building Property Dependent

F = ai a W Ax (Eq. 13.3-4)p p

Fp

(min) = 0.3 SDS

Ip

Wp

forSDS=1.00,Fp= 0.30IpWp

p max = . DS p p forSDS=1.00,Fp= 1.60IpWpwhere:

ai = the acceleration at level obtained from modal

ana ys s w t = . per ect on . .Ax = torsional amplification factor Eq. 12.8-14



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Nonstructural Importance Factor - Ip

asass gne onstructura omponent mportance actor,

Ip

ThevaluesofI iseither1.0or1.5

InASCE705,thevalueofIpisbased

2. OccupancyCategoryofthestructureorfacility

InASCE705,nonstructuralcomponents/systemswhichareassigned

anIp=1.5arecalledDesignatedSeismic

Systems.



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Nonstructural Component ap and Rp Factors ASCE705haveapandRpfactorsassignedintablesthatareusedinFp

equation.

p . . p

lessthan2.5basedondynamicanalysis.

InASCE705, Rpvaluesrangefrom1.0to12.0.

ThevaluesofRpcanbeassignedbasedonthe ductilityand

deformabilitycapacity.

InASCE705thereonly2footnotestotheapandRptables.



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p p Selected Architectural Components

ASCE 7-02 ASCE 7-05

Component

ap Rp ap Rp

Cantilever Parapets 2.5 2.5 2.5 2.5

Exterior Walls* (rigid diaph.) 1.0 2.5 1.0 2.5

Partitions* (rigid diaph.) 1.0 2.5 1.0 2.5

Ceilings 1.0 2.5 1.0 2.5

Penthouses (not an 2.5 3.5 2.5 3.5

Signs and Billboards 2.5 2.5 2.5 2.5

Access Floors* (special) 1.0 2.5 1.0 2.5


Storage Cabinets 1.0 2.5 1.0 2.5


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p p va ues or rc tectura omponentsfor Ca = 0.40, SDS = 1.0, Ip = 1.0

rc ec ura omponen -

z = 0 z = h

-

z = 0 z = h

Cantilever Parapets 0.40 1.20 0.40 1.20

Exterior Walls 0.30 0.48 0.30 0.48

Partitions 0.30 0.48 0.30 0.48

. . . .

Penthouses (not an extension) 0.30 0.86 0.30 0.86

. . . .

Access Floors (special) 0.30 0.48 0.30 0.48

Storage Cabinets 0.30 0.48 0.30 0.48



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o ar son o ap an p va ues orSelected MEP Components

Mech./Elect. Component ASCE 7-02

ap Rp

ASCE 7-05

ap Rp

. . . .

Ai r side equipment 1.0 2.5 2.5 6.0

Wet side e ui ment 1.0 2.5 1.0 2.5

Emergency Battery Racks 1.0 2.5 1.0 2.5

Stacks, towers braced below cg 2.5 2.5 2.5 3.0

Vibration Isolated Equipment* 2.5 2.5 2.5 2.0 2.5

Piping ASME Welded 1.0 3.5 2.5 12.0


Piping threaded joints 1.0 2.5 2.5 4.5


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p p va ues or ec . ec . o onen sfor Ca = 0.40, SDS = 1.0, Ip = 1.0

Mech./Elect. Component ASCE 7-02

z = 0 z = h

ASCE 7-05

z = 0 z = hTanks and Vessels w/o skirts 0.30 0.48 0.30 0.48

Air side equipment 0.30 0.48 0.30 0.50

Wet side equipment 0.30 0.48 0.30 0.48

Emergency Batteries/Tanks 0.30 0.48 0.30 0.48

Stacks, towers braced below cg 0.40 1.20 0.33 1.00

ra on so a e qu pmen . . . - . . - .

Piping ASME Welded 0.30 0.34 0.30 0.30


. . . .


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Nonstructural Relative DisplacementDemands

ASCE705 MaximumRelativeDisplacementsforDBElevelmotions

aretobeconsidered

InASCE705

RequiredforArchitecturalComponentswhichposealife

RequiredforMech/ElectcomponentsandsystemswhereIpgreaterthan1.0.

Exceptforglazing nospecificacceptancecriteriaisprovidedNorequirementtostaywithinelasticlimitsorallowables



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DesignandDetailingRequirementsof

Architectural Com onents

In2006IBC/ASACE705

1. Specificdemandsexteriorwallsand

connections2. SuspendingCeilings CISCA&ASTM

standards

. az ng r capac y .

4. AccessFloors specialaccessfloordetails


.


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DesignandDetailRequirementsfor

Mechanical and Electrical E ui ment

In2006IBC/ASCE705

1. Sprinklersystems NFPA13withamendments

2. EscalatorsandElevators ASMEA17.1

3. Vessels ASMEB&PV4. Piping ASCEB31.1&NFPA13

5. HVACDucting (SMACNAnotspecificallyreferenced)

6. Li htin fixtures Prescri tivedetailre uirements

7. ManyspecificprescriptivedetailsforMechanicalandElectricalEquipment Section13.6.5.5



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SpecialCertificationRequirementsforCertain

DesignatedSeismicSystems(I =1.5)

InChapter13ofASCE705 Seismicqualificationrequiredfor

1.Activemechanicalandelectricale ui mentthatarere uiredtofunctionfollowingaDE

2.Componentscontaininghazardouscontents

Qualificationtodemonstratefunctionalit afterbein sub ecttoaDEtobedeterminedbyeither:

1.Shaketabletesting ICCESAC156,2004(latest2010)

2.ExperienceData

3.Analysis(extremelydifficultforactiveequipment)

Certificationrequiredbysupplierindicatingcompliance


seismicallyqualifiedbytestingorexperiencedata


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AC156

SeismicQualificationbyShakeTableTestingof

CompanionDocumentto2006IBC/ASCE705

AcceptanceCriteriapublishedbyICCEvaluationServices

Firstpublished

in

2000,

latest

version

2010

Providestestingprotocolandtestspectradefinition

TestSpectraistieddirectlytoF forceequation

AcceptanceCriteriatiedtoIpfactor.ForIp=1.5,itemmuchfunctionfollowingtest



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AC156

TEST

SPECTRA

AtRoof(max) AFLX=1.6SDS andARIG=1.2SDS

AtGround

AFLX=

SDSand

ARIG=

0.4

SDS

Horz. 5% DampingHorizontal RRS

's)

ARIG

AFLX

er ca

er

ation,

A

(g

AFLX2A

FLX(f )

fFLX

AFLX

ARIG

2

3

ponse

Accel

Vert.

AFLX(f )

fFLX

3

2

10 fFLX

SpectralRe

15 fFLX

AFLX


fFLX

16.70.1 f0

33.3

Frequency , f (Hz)


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ProductSpecificCertificationCriteria

Under Develo ment

CeilingSystems ASTMA580

HVACEquipment ARI

Expectotherssoon

Needtodevelopformalexperiencedatacertificationcriteria



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SteelStorageRacks

Not

Really

a

Nonstructural

Component

ConnectionTesting

RMISpecificationfortheDesign,Testing,Utilizationof,



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ChangestoChapter13inASCE710 enera prov s onsan exemp ons

Seismicqualificationandcertificationof

Seismicrelativedisplacements

Ceilingprovisions

eorgan za ono mec an ca e ec r ca

Elevatorswitchrequirements



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ASCE/SEI710

WaspublishedinApril2010 SeismicChaptersstill11 23

y

Areasofchangesaregenerallyidentifiedbydarkverticallineinmarginbutnotalways

um ero pages ncrease ya out pr mar ycause ychangeinFontSize.

Eratta gotowww.Seinstitute.orgclickonpublications,clickonerra a,c c on

TherewillbeanenhancedseismiccommentaryforASCE/SEI710publishedbyASCE/SEIinthenextyear.Veryvaluable



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ChangestoSection13.1General

EgressstairsaddedtolistofcomponentsinSection13.1.3thatare

p .

motions.

Furniture(exceptstoragecabinetsasnotedinTable13.51)and

. .

itemsexemptfromtherequirementsofChapter13.

Addedclarificationthatsmallequipmentitemsmustbepositivelyif

. . . ,

Forequipmentusingreferencestandardsastheirbasisofdesign

specifiedthatanchoragerequirementshallnotbethosespecifiedin


.


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Generalprovisions ASCE710

xA

xB

xA

xB

hy

hx

hy

hx

Case A Case B

A

B

A

B


potential for damage to egress stairs due to differential displacement


displacementdemands


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52/78

Othersmaynotbe

June9,2011 522011MCEERSeminarexit staircase, St. Peters Cathedral, Rome

www.truk.com/ramble/wp-content/uploads/2009


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Exemptions "Li hter"com onentsthatarelowto

ASCE710

thefloor(mustbepositivelyanchored)

Floormountedmotors

2010 John F. Silva

not


exempt


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ChangestoSection13.2

ClarifiedwordinginSection13.2.2onwhatreally

requiresitemsreallyrequireseismiccertificationby

shaketabletestingorexperiencedata.

Permittedinherentlyruggeditemstobeexempt

fromtestingprovideddocumentationisprovided

Ot er

parts

o

t e

equ pment

can

e

se sm ca y

certifiedbyanalysisperSection13.2.1.



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Qualificationandcertificationfor I = 1.5 com onents aka Desi nated Seismic S stems

ASCE710

installationofa

active


www.mooreelect.co.uk/Contracts_2006.htm


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Section13.3SeismicDemandson

NochangestotheseismicforceequationsinSection13.3.1.

ReviseddisplacementdemandbymultiplyingitbyI (notIp)

correctsanissue displacementdemanddeterminedper

nonstructuralcomponentsforessentialfacilitieshadless

displacementdemandrequirementthatnormaloccupancies.

.

fornonstructuralcomponentwillnowbethesameforboth.



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xA

xA

Seismicrelativedisplacement ASCE710

xB

xB

hy

hx

hy

hx

Case A Case B

A

B

A

B

2009 NEHRP Recommended Seismic Provisions for New

Buildings and Other Structures



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ASCE710

d xeC -

where

eI

dC = the deflection amplification factor

June9,2011 582011MCEERSeminare

I

xe = the deflection as determined by an elastic analysis

= the (structure) importance factor


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ChangestoSection13.4

Added Requirement in Section 13.4.1 for determining component anchorage, Rp can not be takengreater than 6.0

Significantly revised Section 13.4.2 Anchors in Concrete and Masonry

- added section referencing TMS 402/ASCI 530/ASCE 5 required anchors in Masonry to bedesigned as ductile steel elements unless ductile yielding is provided in attachment

- totally revised anchorage to concrete section.

Post installed anchorage need to be pre-qualified.

Added exception for Power Actual Fasteners in Section 13.4.5 that allows fasters to be used inlight load situations for distributed systems (90 lb maximum in concrete and 250 lb maximum ins ee

In Section 13.4.6 Friction Clips (generally prohibited for SDC D, E or F), allows C-type beam andlarge flange clamps to be used provided restraining straps equivalent to those required by NFPA13 are used.



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Componentanchorage ASCE710

piping

reorgfor

2011Supp.


o u

exception

(notshown)


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attachment

for

Mpyieldofthe

N



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p DS p

p

0.4a S W zF 1 2

h

Areview

ASCE705componentanchorage

ASCE705

p

pI

F 0.3S I W

13.4.2 Anchors in Concrete or MasonryAnchors embedded in

concrete or masonry shall be proportioned to carry the least of thefollowing:

a. . t mes t e orce n t e component an ts supports ue to t e

prescribed forces.

b. The maximum force that can be transferred to the anchor by the

p DS p pF 1.6S I W

.

The value of Rp used in the Section 13.3.1 to determine the forces in

the connected part shall not exceed 1.5 unless:

What was

written

a. The component anchorage is designed to be governed by the

strength of a ductile steel element, or

b. The design of post-installed anchors in concrete used for the


in accordance with ACI 355.2, or

c. The anchor is designed in accordance with Section 14.2.2.17.


63/78

13.4.2 Anchors in Concrete or MasonryAnchors embedded in

concrete or masonry shall be proportioned to carry the least of the

ASCE705

a. 1.3 times the force in the component and its supports due to

the prescribed forces.

b. The maximum force that can be transferred to the anchor by

the component and its supports.

The value of Rp used in the Section 13.3.1 to determine the forcesin the connected part shall not exceed .5 unless:

a. something else yields before the anchor failsOR

b. the anchor is ualified in accordance with ACI 355.2 desi nedWhatwas

in accordance with ACI 318-05 Appendix D and meets therequirements of IBC Section 1908.1.16.



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Whywasthisdone?ASCE

705

s ex rep ace eprev ousrequ remen or

aboltlengthtodiameterratioof8.

Itwasintendedtomarrytheductility

requirementsofAppendixDwiththespecial

. . .



65/78

NewConcreteAnchorageRequirements

Greatlysimplified

DesignanchorageperACI318AppendixD

PostInstalledAnchors shallbeprequalifiedperACI355.2or

.

RemovestheRp=1.5andthefactorof1.3.

TobeconsistentwithACI31811 wewillneedtosoondefine

an ofactorfornonstructuralcomponentsorthedefaultwillbe2.5.ThiswouldneedtoaddedtoSection13.4.1



66/78

RestrainingStrapsrequiredforCclamps



67/78

Section13.5ArchitecturalComponents

RevisedTable13.51(Rptable)toapplytostoragecabinets

AddedtoTable13.51permanentfloorsupportedlibraryshelving,bookstacksandbookshelvesover6feettallincludingcontents ap=1.0andRp=2.5

SignificantlyrevisedSuspendedCeilingSection13.5.6byreferencingASTMB580formostoftherequirementsinstead

of

CISCA.

Since

most

of

the

requirements

in

ASCE

7

05

are

nowinASTMB580,wegreatlyreducedtheaddedre uirements.



68/78

CeilingsASCE

710

Exemptionforgypsumboardceilings

ReferencetoASTME580forindustrystdconstruction

Fixtoareasubdivisionrequirement




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ASCE710

500 ft.100 ft.

ceiling area

25 ft.

June9,2011 692011MCEERSeminar 5 ft.


70/78

Section13.6Mechanicaland

NochangestotheRpTable(Table13.61)

Signi icant yreorganize ,com ine an c ari ie Section13.6.5.5 AdditionalRequirementsforComponentSupports,13.6.5.6 Conduit,CabletrayandotherElectricalDistributionSystems raceways and13.6.7 Ductworktocombinerequirements

RevisedSection13.6.8 PipingSystemto referenceASMEandNFPA13standardsinfirstsectionandprovideallowablestressesformaterialsnotcoveredbythestandards



71/78

ReorganizationofMEPsectionsASCE

710

Exceptions/specialcasesfollow Term"raceways"adoptedforelectrical

distributionsystems

Term"tradesize"adoptedforconduit

Ductwork(formerlyHVAC)similarlyreorganized

Pipingexceptions:ASMEB31.1,NFPA13,ASME17.1




72/78

Elevatorswitchrequirements

TriggermodifiedtoconformtoASMEA17.1

Intendedtoavoidunnecessaryshutdowns,enablefasterrestarts(switchinmachineroom)

Verticalorientation,locatenearcolumnwithatriggerlevelof0.15g

Ifnotpossibletolocatenearcolumn,horizontal0.2gatgroundfloor,0.5gaboveground(OSHPD)



73/78

BackgroundonAC156

ApproachedinLate1998/Early1999byPhilCaldwellof.

HewantedtodoshaketabletestingtoqualifyhiselectricalequipmenttotheUBC.Heneededatestspectra.

,ICCESandgetaAcceptanceCriteriaadoptedbythemthroughtheICCESHearingProcess.Firstadoptedasearly2000.

NotethatseismicqualificationbyshaketabletestingforbuildingequipmentstartedwithATC306in1978.


.


74/78

MisunderstandingsaboutAC156

AC156wasconceivedasagenerictestspectrathatistiedto

t eFpequationinC apter13.

Itnotintendedtobedependentonbuildingpropertiesor

youwant.

Itwasconceivedthatmostsupplierswouldtestforthe

maximumspectrashape(theroofcutoffshape).

Thetestmotionisdeemedtobeafloormotionnotaground


.


75/78

MisunderstandingsaboutAC156(continued)

AC156isalineinthesandjustliketheFpequationisalinein.

buildingswherethefloorspectralaccelerationswillbeexceededatsomefrequenciesandotherswhereitismuch

.

WithAC156youseismicallyqualifyequipmenttoaspectralvalueSa(5%damped)whichisthepeakofthespectra(Aflx).YoucancomparetheSaqualificationvaluewith1.6SDSto

determinethemaximumSDSwheretheequipmentisqualifiedifitisroofmountedor1.0SDSifitmountedatgrade.



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Thereisnosuchthingas1timesAC156,2timesAC156,or.

youritem/equipmentisseismicallyqualifiedtoavalueofSagsthatcorrespondstoAflx.

whichis2/3rdsofthegroundspectra.Itsrecognizedatthecenterofaflooritwillbemuchgreater.Thereisvirtuallynomeasuredverticalgroundmotionrecordsatthecenterofafloor.

Todate,theNEHRPRecommendedProvisionsandASCE7haverefusedtoexplicitlydefineverticalspectrarequirements



77/78


ThevalueofAC156isthatitisgenericandtiedto

theFpvaluessothatasupplierneedstoonlygo

throughonetestcampaign.Ifheneededto

separa e yqua yan emo equ pmen oreac project,thecostwouldbeprohibitiveandtesting

.

Thatsexactlywhathappened.Suppliershaveand



78/78

ThanksforYourAttention!

ny ues ons


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