日本钢结构设计标准样本

CHAPTER1GENERAL

ScopeofApplication

ThisStandardappliestothestructuraldesignofsteelbuildings.TheStandard，however，neednotapplytostructuraldesignsbasedonspecialresearchstudies.

StructuralSafetyVerificationTests

WhereadesignininvolvesconnectionandotherstructuraldetailsnotexpresslyprescribedinthisStandard，thestructuralsafe&ofsuchdetailsshallbeprovedbytestsorbyotherappropriatemeans.

EnlargementofSection

Sectionsofvariousstructuralelementsshallbeenlargedasrequired，withdueconsiderationforpracticallimitationinprecisionofstructuraldesigns，inadequacyinconstructionalworkmanship，andsuchadversefactorsasrusting，corrosionandwearofsteelmaterials.

Nomenclature

A Grosssectionalarea；nominalbodyareaofahigh-strengthbolt；orsumofsectionalareasofcolumncomponents(mm2)

AN Netsection(mm2)

Ad Sectionalareaoflacingelement；ortotalsectionalareaofapairoflacingelementsinthecaseofdoublelacing(mm2)

Af Cross-sectionalareaofcompressionflange；orcross-sectionalareaofeitherflange(mm2)

Ap Sectionalareaofpartsincontact(mm2)

As Cross-sectionalareaofverticalorhorizontalstiffeners(mm2)

Aw Cross-sectionalareaofwebplate(mm2)

a Equivalentarealossduetorivet，boltorhigh-strengthboltholes(mm2)；orspacingofintermediatestiffeners(mm)

a0 Netarealossduetorivet，boltorhigh-strengthboltholes(mm2)

b Widthofcompressionelementfreeatoneedgeandfixedattheother；widthofrockerorroller；orlongitudinalspacingorpitchofconsecutiveholes(mm)

，butnotlargerthan2.3

Bendingcoefficientdependentuponmomentgradient

D Nominaloutsidediameterofsteelpipe；oroutsidediameterofmainsteelpipe(mm)

d Widthofelementstiffenedalongtwoedges；outsidediameterofbranchpipe；widthofwebplate；ordiameterofpin(mm)

d1 Minimumwidthoftheportionofwebplatedividesbyverticalorhorizontalstiffener(mm)

E Modulusofelasticity(N/mm2)

e Distancebetweenaxesofgravityofcomponents(mm)

F Basicvalueusedindeterminingallowablestresses(N/mm2)

(N/mm2)

f Allowablestressinmemberssubjecttorepeatedstressvariation(N/mm2)

fb Allowablebendingstress(N/mm2)

fb1 Allowablebendingstressinbearingplatesandsimilarelementssubjecttoout-of-planebending(N/mm2)

fb2 Allowablebendingstressinpinssubjecttobending(N/mm2)

fc Allowablecompressivestress(N/mm2)

fc’ Allowablecompressivestressinthetoeofthewebfilletofrolledshapesorbuild-upI-shapedmembers(N/mm2)

fl Allowablebearingstressinplatesinrivetedorboltedjoints(N/mm2)

fp1 Allowablebearingstressforcontactareaofpinsandforothermilledsurfaces(N/mm2)

fp2 Allowablebearingstressforrockersorrollers(N/mm2)

fs Allowableshearstress(N/mm2)

fs0 Allowableshearstressforhigh-strengthbolts(N/mm2)

fst Allowableshearstressforhigh-strengthboltssubjecttocombinedtensionandshear(N/mm2)

ft Allowabletensilestress(N/mm2)

ft0 Allowabletensilestressforrivetsorbolts(N/mm2)

fts Allowabletensilestressforrivetsorboltssubjecttocombinedtensionandshear(N/mm2)

g Transversespacingbetweenfastenergagelines(mm)

h Depthofbeam(mm)

I0 Momentofinertiaofintermediatestiffeners(mm4)

IL Momentofinertiaofhorizontalorverticalstiffener(mm4)

IS Requiredmomentofinertiaofthestiffenersoncompressionflanges(mm4)

i Radiusofgyration，takenaboutanaxisintheplaneofweb，ofateesectioncomprisingthecompressionflangeplusone-sixthofbeamdepthradiusofgyrationofasectionwithrespecttoaxissubjecttobuckling；orradiusofgyrationofhorizontalorverticalstiffenersontheweb(mm)

i1 Theleastradiusofgyrationofsectionalelementsofcompressionmembers(mm)

L Effectivelengthofweldinbranchconnectionofsteelpipes(mm)

l Lengthofmember；orlengthofdistributedload(mm)

lb Unsupportedlengthofcompressionflange(mm)

ld Lengthoflacingelement(mm)

lk Effectivelengthofcompressionmembersubjecttobuckling(mm)

l1 Spacingofseparatorsortieplates；orlengthofholeinmemberswithcoverplateshavingholes(mm)

l2 Longitudinalcomponentofthelengthoflacingofabuilt-upmember(cm)

M Bendingmoment(N・mm)

M1 Largerbendingmomentaboutthestrongaxisattheendofamember(N・mm)

M2 Smallerbendingmomentaboutthestrongaxisattheendofamember(N・mm)

m Numberofcomponentsorgroupsofcomponentsconnectedbylacingortieplates

N Compression(N)

N1 Largercompression(N)

N2 Smallercompression(N)

n Numberofstructuralplanesformedbylacingortieplatesinbuilt-upmembers；ornumberofverticalorhorizontalstiffeners

P Concentratedtransverseloadorreaction；orcompressionforcomputationofbearingstress(N)

p Spacingofholes(mm)

Q Shear(N)

r Radiusofcurvatureofrockerorroller(mm)

T Tension(N)

T0 Designbolttensionforhigh-strengthbolt(N)

t Thicknessofplate；wallthicknessofpipe；thicknessofwebplate；orplatethicknessofpin(mm)

t0 Distancefromedgeofflangetotoeofwebfillet(mm)

Zc Sectionmodulusofcompressionsideofcross-section(mm3)

Zt Sectionmodulusoftensionsideofacross-section(cm3)

α Distributionfactorforcompressivestress

γ Fatiguefactor

θ Intersectinganglebetweentwopipes

Λ Criticalslendernessratio

λ Slendernessratioofcompressionmember(lk/i)

λy Slendernessratioofbuilt-upcompressionmemberassumedtobuckleasanintegratedmember

λye Effectiveslendernessratioofbuilt-upcompressionmembers

σ Maximumcompressivestressinwebplate(N/mm2)

σ0 Allowablecompressivestressinplatesubjecttobuckling(N/mm2)

cσb Bendingstressofextremefiberincompression(M/Zc)(N/mm2)

tσb Bendingstressofextremefiberintension(M/Zt)(N/mm2)

σc MeancompressiveStress(N/A)(N/mm2)

σP Bearingstress(N/mm2)

σt Meantensilestress(T//AN)；ortensilestresswhichisproportionaltotheforceactinguponbolts(N/mm2)

σx,σy Normalstressesperpendiculartoeachother(N/mm2)

σ1,σ2 Largerabsolutevalueandsmallerabsolutevalueofstressesattheupperandlowerlimitsofstressrangeformemberssubjecttorepeatedstressvariation(N/mm2)

τ Shearstressproducedinrivetsorbolts；ormeanshearstressinwebplate(N/mm2)

τ0 Allowableshearstressinplatesubjecttobuckling(N/mm2)

τxy Shearstressintheplaneofnormalstresses，σxandσy(N/mm2)

CHAPTER2DRAWINGPRACTICE

2.1 RulesofRepresentation

DrawingsshallbepreparedincompliancewithJISZ8302[GeneralRulesforTechnicalDrawing]，JISA0150[DrawingOfficePracticeforArchitectsandBuilders(GeneralRules)]，JISZ8201[MathematicalSymbols]andJISZ3021[GraphicalSymbolsforWelding].

2.2 ItemsofInformationtoBeGivenOnDrawings

Drawingsshallgivecompleteinformationondimensions，sectionalshapesandrelativepositionsofrespectivemembers.Theyshallalsoshow，intermsofdimensions，allfloorlevels，columncenters，andjointsandconnectionsofmembers.Drawingsshallbepreparedtoscaleslargeenoughtogivetheforegoinginformationwithclarity.

Wherenecessary，drawingsshallshowthequalitiesofsteelmaterialstobeused.

Whereboltsorhigh-strengthboltsaretobeused，boltqualitiesshallbedistinctlyshownonthedrawingsasnecessary.

Cambersoftrussesandbeamsshallbeshownonthedrawingasnecessary.

Wherepartsaredesignedformetal-to-metalcontactasincolumnsbearingonbaseplates，incolumnsplicesorinstiffenersbearingonbeamflanges，theextentofmillingormachiningrequiredforendsofsuchpartsshallbeindicatedondrawingsasnecessary.

CHAPTER3CALCULATIONOFI.OADSANDSTRESSES

3.1 GeneralLoads

Loadstobeusedinstructuralcalculationshall，asarule，bethoseprescribedintheEnforcementOrderoftheBuildingStandardLaw.

3.2 Impact

Forstructurescarryingliveloadswhichinduceimpact，thedesignloadsshallbeincreasedinaccordancewiththeassessedeffectsofsuchimpact.Wheretheeffectsofimpactarenotbasedonmeasurement，thedesignloadsmaybeincreasedinaccordancewiththefollowing:

Forstructuralsupportsofelevators:

100%oftheelevatorWeight

Forstructuralsupportsofoverheadtravelingcranes:

Wherethespeedislessthan60m/minute

10%ofthewheelload

Wherethespeedis60m/minuteorover

20%ofthewheelload

Ifjointlessrailisused，"60m/minute''intheaboverequirementmaybereplacedby"90m/minute.”

Forsupportsofmotorizedequipment:

Notlessthan20%oftheequipmentweight

Forsupportsofequipmentdrivenbyreciprocatingengines:

Notlessthan50%oftheequipmentweight

Forhangerssuspendingfloorsorbalconies:

30%oftheliveloadthereon

3.3 CraneRunwayLateralForces

BrakingForceintheDirectionofCraneTravel

Thisshallbetakenas15%ofeachwheelloadsubjecttobrakingforce，asappliedtothetopofthecranerail.

HorizontalForcesNormaltotheDirectionofCraneTravel

Cranesupportinggirdersonbothendsofacraneshallbeconsideredassubjectedsimultaneouslyto10%ofthecranewheelloadsactingnormaltothedirectionofcranetravel.Forcomputation，thecranetrolleyandliftedloadshallbeassumedtobeinthemostunfavorablecondition.

DiagonalTension

Wheretheloadtobeliftedispulledbyacraneinadiagonaldirection，thestressinducedinthestructurebysuchoperationshallbetakenintoaccount.

EarthquakeForces

Earthquakeforcesactingoncranesshallbeassumedasappliedatthetopofthecranerail.Unlessotherwisespecified，theweightofliftedloadmaybedisregardedincomputingtheweightofacrane.

3.4 RepeatedVariationofStresses

Formemberssubjectedtorepeatedvariationofstresses，thedesignstressesshallbeincreasedtoallowfortheeffectsofmaterialfatigueinaccordancewithChap.7.

3.5 ThermalStresses

Forstructuressubjecttolargevariationoftemperature，thermaleffectsshallbegivendueregardinstructuraldesign.

3.6 CombinationofStresses

StressesineachstructuralcomponentshallgenerallybecombinedinaccordancewithTable3.1，andfurtherasspecifiedbelow:

Table3.1CombinationofStress

Loadingconditions

Forgeneralareas

Forareassubjecttoheavy

snowfall

Permanentloading

Undernormalload

G+P

G+P+S

Temporaryloading

Undersnowload

Understormload

Underseismicload

G+P+S

G+P+W

G+P+K

G+P+S

G+P+W

G+P+S+W

G+P+S+K

Symbols

G : StressduetodeadloadasprescribedbytheEnforcementOrderoftheBuildingStandardLaw

P : StressduetoliveloadasprescribedbytheaforesaidOrder

S : StressduetosnowloadasprescribedbytheaforesaidOrder

W : StressduetowindloadasprescribedbytheaforesaidOrder

K : StressduetoseismicloadasprescribedbytheaforesaidOrder

Incombiningstresses，thestressinducedbycranesinstructuralsupportsshallberegardedasstressduetoliveload.

Wheremorethanonecranesimultaneouslyactsonstructuralsupports，thestressesduetocranesshallbecombinedforthemostunfavorablecasewhichispresumableinthecourseofactualcraneoperation.

Fordesigncomputationofcolumnjointsandcolumnbases，stresscombinationsinwhichstormorseismicloadisinvolvedshallalsobeinvestigatedforcaseswhereliveloadsaredisregarded.

CHAPTER4MATERIALS

4.1 Qualities

Unlessotherwiseprovided，structuralmaterialsshallbeofthequalitiesspecifiedintheapplicablestandardslistedinTable4.1.

Table4.1StandardsPrescribingQualityofStructuralMaterials

Numbers

Titles

JISG3136

RolledSteelforConstructionStructure:

SN400A，SN400B，SN400C，SN490BandSN490C

JISG3101

RolledSteelforGeneralStructure：

SS400，SS490andSS540

JISG3106

RolledSteelforWeldedStructure：

SM400A，BandC；SM490A，BandC；SM490YAandYB；SM520BandCandSM570

JISG3114

JISG3475

CarbonSteelTubesforConstructionStructure:

STKN400W，B，STKN490B

JISG3444

CarbonSteelTubesforGeneralStructuralPurposes:

STK400andSTK490

JISG3466

CarbonSteelSquarePipesforGeneralStructuralPurposes:

STKR400andSTKR490

JISG3138

RolledSteelBarforConstructionStructure:

SNR400A，B，SNR490B

JISG3350

LightGaugeSteelsforGeneralStructures：SSC400

JISG3353

JISB1186

SetsofHigh-StrengthHexagonBolt，HexagonNutandPlain

WashersforFrictionGripJoints

JISB1178

JISG3104

RolledSteelforRivets

JISZ3211

CoveredElectrodesforMildSteel

JISZ3212

CoveredElectrodesforHighTensile-StrengthSteel

JISZ3351

JISZ3352

SteelWireforSubmergedArcWelding

JISG5101

CarbonSteelCastings：SC480

JISG5102

CastingforWeldingStructure：SCW410，SCW480

JISG5201

JISG3201

CarbonSteelForgings

4.2 ShapesandSizes

Table4.2StandardPrescribingShapesandSizesofStructuralMaterials

Numbers

Titles

JISG3192

Dimensions，WeightandPermissibleVariationsofHotRolledSteelSections

JISG3193

Dimensions，WeightandPermissibleVariationsofHotRolledSteelPlates，SheetsandStrip

JISG3194

Shape，Dimensions，WeightandToleranceforHotRolledFlatSteel

JISG3191

Shape，Dimensions，WeightandToleranceforHotRolledSteelBarandBar-in-Coil

JISG3475

JISG3444

CarbonSteelTubesforGeneralStructuralPurposes

JISG3466

CarbonSteelSquarePipesforGeneralStructuralPurposes

JISG3350

LightGaugeSteelforGeneralStructures

JISG3353

JISB1186

SetsofHigh-StrengthHexagonBolt，HexagonNutandPlainWashersforFrictionGripJoints

JISB1178

BasedBolts

JISB1180

HexagonHeadBolts

JISB1181

HexagonNuts

JISB1256

PlainWashers

JISB1214

HotHeadedRivets

JISE1101

Rails

JISE1103

LightRails

JISA5540

TurnbucklesforStructuralPurpose

Unlessotherwiseprovided，structuralmaterialsshallbeoftheshapesandsizesprescribedinTable4.2.

4.3 Constants

Physicalconstantsforstructuralmaterialsshall，ingeneral，betakenasthevaluesgiveninTable4.3.

Table4.3PhysicalConstantsforStructuralMaterials

Material

Modulusofelasticity(N/mm2)

Shearmodulus(N/mm2)

Poisson’sratio

Coefficientoflinearexpansion

(1/℃)

Steel,

Caststealand

Forgedsteel

205,000

79,000

0.3

0.000012

CHAPTER5ALLOWABLESTRESSES

5.1 StructuralSteel

AllowablestressesforstructuralsteelunderpermanentloadingshallbedeterminedonthebasisofthevaluesofFgiveninTable5.1.

Table5.1ValuesofF(N/mm2)

Steelforconstructionstructures

Steelforgeneralstructures

Steelforweldedstructures

SN400

SNR400

STKN400

SN490

SNR490

STKN490

SS400

STK400

STKR400

SSC400

SS490

SS540

SM400

SMA400

SM490

SM490Y

SMA490

STKR490

STK490

SM520

SM570

F

Thickness(mm)

t≤40

40<t≤100

235

215

325

295

235

215

275

255

375

―

235

215

325

295

355

335

t>75，325

400

400

AllowableTensileStress

Onthenetsectionasdefinedin13.1

(5.1)

where

ft : allowablebendingstress(N/mm2)

AllowableShearStress

(5.2)

where

fs : allowableshearstress(N/mm2)

AllowableCompressiveStress

Onthegrosssection:

Whenλ≤Λ

(5.3)

Whenλ>Λ

(5.4)

(5.5)

where

fc : allowablecompressivestress(N/mm2)

λ : slendernessratioofcompressionmember(see11.1)

E : modulusofelasticity(N/mm2)

Λ : criticalslendernessratio

Onthewebofrolledshapesorbuilt-upIsectionsatthetoeofthefillet:

Regardlessoftherequirementof(a)above，allowablecompressivestressshallbeascomputedbyFormula(5.6)below.

(5.6)

where

fc’ : allowablecompressivestress(N/mm2)

AllowableBendingStress

Forflexuralmemberssuchasrolledbeams，plategirdersandotherbuilt-upmembershavingsymmetricalaxisintheloadedplane(exceptforbox-typemembers)，andmeetingthewidth-thicknessratiorequirementofChap.8andsubjectedtobendingaboutthestrongaxis，allowablebendingstressonextremefibersincompressionshallbetakenasthelargervaluecomputedbyFormula(5.7)or(5.8)；however，suchstressshallnotexceedftonextremefibersincompressionorintension.

(5.7)

(5.8)

where

fb : allowablebendingstress(N/mm2)

lb : unbracedlengthofcompressionflange(mm)

i : radiusofgyration，takenaboutanaxisintheplaneofweb，ofateesectioncomprisingthecompressionflangeplusone-sixthofthedepthofbeam(mm)

，butnotmorethan2.3

M2andM1arethesmallerbendingmomentandthelargerbendingmoment，respectively，aboutthestrongaxisattheendsofamembersubjecttobuckling.(M2/M1)takesapositivevalueinthecaseofsinglecurvatureandanegativevalueinthecaseofdoublecurvature.WheremomentonthecenteroftheportionsubjecttobucklingislargerthanM1，Cistakenasunity.

h : depthofbeam(mm)

Af : cross-sectionalareaofcompressionflange(mm2)

Λ : (seeFormula5.5)

Fortubularandbox-typesteelmembers，formembershavingaxesofsymmetryintheloadedplane，subjectedtobendingabouttheweakaxisandmeetingthewidth-thicknessratiogivinginChap.8,andforgussetplatesloadedwithintheirplane，allowablebendingstressesonextremefibersintensionandcompressionshallbetakenasft.

Allowablebendingstressonextremefibersincompressionforchannelsandmembersnothavingaxesofsymmetryintheloadedplaneandmeetingthewidth-thicknessrequirementofChap.8shallbeasobtainedfromFormula(5.8)，butnotgreaterthanft.

AllowablebendingstressinbearingplatesandsimilarelementssubjecttobendingoutsidetheirplaneshallbeasobtainedfromFormula(5.9).

(5.9)

where

fb1 : allowablebendingstress(N/mm2)

AllowablebendingstressinpinssubjectedtobendingshallbetakenasthevaluecomputedbyFormula(5.10).

(5.10)

where

fb2 : allowablebendingstress(N/mm2)

AllowableBearingStress

Forcontactareaofpinsandbearingstiffenersandforothermilledsurfaces，theallowablebearingstressshallbeobtainedfromFormula(5.11).

(5.11)

Whenpartsincontactareadifferentinquality.Fshallbetakenasthesmallervalue，andbearingstressopshallbeobtainedbyFormula(5.12).

(5.12)

where

fp1 : allowablebearingstress(N/mm2)

P : compression(N)

Ap : generally，sectionalareaofpartsincontact(mm2)；forpin/connections，Ap=tdwheret=platethicknessofpin(mm)andd=diameterofpin(mm)

σp : bearingstress(N/mm2)'

Forrockersorrollers，allowablebearingstressshallbecomputedbyFormula(5.13).

(5.13)

Whenpartsincontactaredifferentinquality，Fshallbetakenasthesmallervalue，andbearingstressopshallbeobtainedbyFormula(5.14).

(5.14)

where

fp2 : allowablebearingstress(N/mm2)

P : compression(N)

E : modulusofelasticity(N/mm2)

b : widthofrockerorroller(mm)

r : radiusofcurvatureofrockerorroller(mm)

σp : bearingstress(N/mm2)

Rivets，BoltsandHigh-StrengthBolts

Allowabletensileandshearstressesofrivets，boltsandhigh-strengthboltsunderpermanentloadingshallbeasgiveninTable5.2.Allowablestressesshallbecomputedforthebodyareaoffasteners.

Table5.2AllowableStressesonRivets，BoltsandHigh-StrengthBolts(N/mm2)

Materials

Tension

Shear

Rivets

SV330andSV400

155

120

Bolts

Semi-finishedboltsmadeofSS400andSM400

OtherSemi-finishedbolts

120

0.5F

70

0.3F

High-strengthbolts

F8T

F10T

(F11T)

250

310

(330)

120

150

(160)

High-strengthboltsshallbegiventhedesignbolttensiongiveninTable5.3，andtheyshallbesoarrangedastotransmitshearbyfriction.

Table5.3DesignBoltTensionforHigh-StrengthBolts(kN)

Gradesofhigh-strengthbolts

NominalSizes

M12

M16

M20

M22

M24

M27

M30

F8T

F10T

45.2

56.5

80.4

101

126

157

152

190

181

226

229

286

283

353

AllowablebearingstressinplatesconnectedbyrivetsOrboltsshallbeascomputedbyFormula(5.15)fortheprojectedareaobtainedbymultiplyingrivetorboltdiameterbythicknessofconnectedplates.Wherecountersunkrivetsorboltsareused，thethicknessofconnectedplatesshallbetakenastheactualthicknessofsuchplateslessone-halfthedepthofrivetorboltheadsunkintheplates.

(5.15)

where

fl : allowablebearingstress(N/mm2)

High-strengthboltedconnectionsneednotberestrictedbytheallowablebearingstress.

Welds

Allowablestressunderpermanentloadingoneffectivethroatofarcweldmaybetakenasthevaluesprescribedbelowprovidedthatweldingelectrodeusedisappropriateforthetypeofsteeltobeweldedandthatweldingisperformedundersatisfactorycontrol.WeldsinSS490andSS540steels，however，shallnotbeallowedtocarryanystress.

Allowablestressesforfilletweld，plugweld，slotweld，flareweld，partial-penetrationweldandthoseoneffectiveareaofweldsdescribedinChap.16andforweldsofbranchconnectionoftubularsteelmembersshallbethesameasallowableshearstressforbasemetal.

Allowablestressforcompletepenetrationbuttweldsshallbethesameasthatforbasemetaltobewelded.

Wheresteelsofdifferentqualitiesarewelded，allowablestressforweldsshallbetakenasthesmallervalueoftheallowablestressesforbasemetals.

CastSteelandForgedSteel

Allowablestressesforcaststeelandforgedsteelmay，whereapplicable，beconsideredthesameasthoseforcorrespondingrolledsteels.

AllowableStressesforSteelMembersSubjecttoCombinedStresses

AllowablestressesformemberssubjecttobothnormalandshearstressshallsatisfyFormula(5.16).

(5.16)

where

σxandσy : twonormalstressesperpendiculartoeachother(N/mm2)

xy : shearstressintheplaneofσxandσy(N/mm2)

AllowableStressesunderTemporaryLoading

IncheckingmembersfortemporaryloadingbythecombinationofstressesdescribedinChap.3，allowablestressesspecifiedinthischaptermaybeincreasedby50%.

CHAPTER6COMBINEDSTRESS

6.1 AxialCompressionandBendingMoment

MemberssubjectedtobothaxialcompressionandbendingmomentshallbeproportionedtosatisfyFormulas(6.1)and(6.2)givenbelow，inwhichσc，cσbandtσbshalltakeabsolutevalues.

(6.1)

and

(6.2)

where

fc : allowablecompressivestress，asappropriate，prescribedin5.1，(3)(N/mm2)

fb : allowablebendingstress，asappropriate，prescribedin5.1.(4)(N/mm2)

ft : allowabletensilestressprescribedin5.1，(1)，(N/mm2)

σc. : N/A=meancompressivestress(N/mm2)

cσb : M/Zc=bendingstressonextremefiberincompression(N/mm2)

tσb : M/Zt=bendingstressonextremefiberintension(N/mm2)

N : compression(N)

M : bendingmoment(N・mm)

A : grosssectionalarea(mm2)

Zc : sectionmodulusofcompressionsideofacross-section(mm3)

Zt : sectionmodulusoftensionsideofacross-section(mm3)

6.2 TensionandBendingMoment

MemberssubjectedtobothtensionandbendingmomentshallbeproportionedtosatisfyFormulas(6.3)and(6.4)givenbelow，inwhichσt，cσband，tσbshalltakeabsoluteValues.

(6.3)

and

(6.4)

where

σt=T/AN : meantensilestress(N/mm2)

T : tension(N)

AN : netsectionasprescribedin13.1(mm2)

Othersymbolshavethesamemeaningsasin6.1above.

6.3 ShearandTension

RivetsandboltssubjecttocombinedshearandtensionshallbesoproportionedthatthetensilestressproducedbyforcesappliedtotheconnectedpartsshallnotexceedthevalueofftsobtainedfromFormula(6.5).

(6.3)

and

(6.4)

where

fts : allowabletensilestressforrivetsorboltssubjecttocombinedtensionandshear(N/mm2)

fto : allowabletensilestressforrivetsorboltsdescribedin5.2，(1)(N/mm2)

τ : shearstresswhichisproducedinrivetsorboltsandwhichshallnotexceedtheallowableshearstressgivenin5.2，(1)(N/mm2)

Forhigh-strengthboltssubjecttocombinedshearandtension，shearstressshallnotexceedthevalueoffstasdeterminedfromFormula(6.6).

(6.6)

where

fst : allowableshearstressforhigh-strengthboltssubjecttocombinedtensionandshear(Nt/mm2)

fso : allowableshearstressforhigh-strengthboltsasprescribedin5.2,(1)(N/mm2)

σ t: tensilestresswhichisproportionaltotheforceactinguponboltsandwhichshallnotexceedtheallowabletensilestressforhigh-strengthboltsasspecifiedin5.2，(1)(N/mm2)

To : designbolttension(N)

A : nominalbodyareaofhigh-strengthbo1t(mm2)

CHAPTER7MEMBERSANDCONNECTIONSSUBJECTTOREPEATEDVARIATIONOFSTRESS

7.1 FatigueFactorandAllowableStresses

Wherethenumberofrepeatedstressvariationsisbelow1×104inthelifeofastructure，thefatigueeffectsneednotbeconsidered.

Wherethenumberofstressvariationsis1×104orover，fatiguefactor(γ)andallowablestresses(f)shallbedeterminedinaccordancewithTable7.1andFormula(7.1).Theupperandlowerlimitsintherangeofstressvariation，however，shallnotexceedthestresspermittedinChaps.5and6forthetypeofsteelandconnectionmaterialused.

(7.1)

Table7.1FatigueFactor(γ)andAllowableStresses(f)

Numberof

Stressrepetitions

γ

f(N/mm2)

105orfewer

Allowablestress，appropriatefortypeofsteel，typeofstressandtypeofconnec-

tionmaterial，asgiveninChaps.5and6.

Over105andupto2×106

Forsteelsandwelds，allowablestressapplicabletoSS400；andforrivets，allowablestressapplicabletoSV330orSV400.

Over2×106

Sameasabove.

Note:

Attheupperandlowerlimitsofstressrange，thestresshavingthelargerabsolutevalueshallbeexpressedasσ1(N/mm2)andthathavingthesmallerabsolutevalueasσ2(N/mm2).Valueofσ2/σ1shall，therefore，bepositiveifσ2andσ1havethesamesignandnegativeiftheyhaveoppositesigns.

Increaseofallowablestressasprovidedin5.6shallnotbepermittedforf.

7.2 Bolts

Boltsshallnotbeusedinconnectionssubjecttorepeatedstressvariation.

7.3 High-StrengthBolts

Effectofrepeatedstressvariationneednotbeconsideredforhigh-strengthboltssubjecttoshearonly.

7.4 Notches

Partswithsharpnotchesshallbesodesignedthatworkingstressinthemwillnotexceed75%ofthevalueoff/γgiveninthischapter.

CHAPTER8WIDTH-TO-THICKNESSRATIOOFPLATEELEMENTS

8.1 Width-to-ThicknessRatioofPlateElements

Suchunstiffenedplateelementsofframeworkasare-subjecttoaxialcompressionorcompressionduetoin-planebendingshallmeettheratioofwidthtothicknessgivenbelow.

ProjectingPlateElementsFreeatOneEdgeandFixedattheOther

Single-anglestrutsandmultiple-anglestrutswithseparators:

(8.1)

wheresymbolshavethesamemeaningsasgivenin(b)below.

Compressionflangesofbeamsandcolumns；anglesorplatesprojectingfromgirders，columnsorothercompressionmembers；stemsoftees；stiffenersasspecifiedin9.3.

(8.2)

where

b : widthofunstiffenedplateelementwhich，inbuilt-upmembers，shallbetakenfromthefreeedgetothefirstrowoffastenersorwelds；thewidthoflegsofangles，flangesofchannelsorzees，stemsofteesandcold-formedlight-gaugesectionsshallbetakenasthefullnom