日本风荷载规范英文版正文

CHAPTER6WINDLOADS–6-1–CHAPTER6WINDLOADS6.1General6.1.1Scopeofapplication(1)Thischapterdescribeswindloadsforthedesignofbuildingsthatrespondelasticallyinstrongwinds.(2)Twodifferentwindloadsaredescribed.Thefirstisforthedesignofstructuralframes,andthesecondisforthedesignofcomponents/claddingofbuildings.6.1.2Estimationprinciple(1)Windloadsforthedesignofbuildingsareindividuallyspecifiedforhorizontalwindloadforstructuralframes,roofwindloadforstructuralframesandwindloadforcomponents/cladding.Thehorizontalwindloadsforthedesignofstructuralframesshallbeindividuallydeterminedinthealong-wind,across-windandtorsionaldirections.(2)Forwindloadforstructuralframes,combinationofeachhorizontalwindloadandcombinationofhorizontalwindloadandroofwindloadshallbeconsideredaccordingtoA6.8.Forcomponentsofcladdingandstructuralframeorparticularjointsofcladdingandstructuralframes,combinationofhorizontalwindloadonstructuralframesandlocalwindloadoncladdingshallbeconsidered.(3)ThewindloadsshallgenerallybedeterminedfromthedesignwindspeeddefinedforeachwinddirectiongiveninA6.1.2.(4)Thereferenceheightisgenerallythemeanroofheightofthebuilding.Thewindloadsarecalculatedfromthevelocitypressureatthisreferenceheight.However,windloadsonlatticetypestructuresshallbecalculatedfromthevelocitypressureateachheight,asshowninA6.6.(5)ThehorizontalwindloadonstructuralframesandtheroofwindloadonstructuralframesaregivenbytheproductofthevelocitypressuregiveninA6.1,thewindforcecoefficientgiveninA6.2,thegusteffectfactorgiveninA6.3andtheprojectedareaorsubjectareaasshownin6.2and6.3.(6)Thewindloadoncomponents/claddingisgivenbytheproductofthevelocitypressuregiveninA6.1,thepeakwindforcecoefficientgiveninA6.2andthesubjectarea.(7)Forrelativelyflexiblebuildingswithlargeaspectratios,thehorizontalwindloadsonstructuralframesintheacross-windandtorsionaldirectionsgiveninA6.4andA6.5shallbeconsidered.Thecriteriaforthisaredescribedin6.1.3(1).(8)Forflexiblebuildingswithverylargeaspectratios,thestructuralsafetyagainstvortex-inducedvibrationandaeroelasticinstabilityshallbechecked.Thecriteriaforthisaredescribedin6.1.3(2).ThewindloadsonstructuralframesandmembersofroundsectionalshapecausedbyvortexinducedvibrationshallbedeterminedbyA6.7.(9)Forsmallbuildingsandstructureswithlargestiffness,asimplifiedprocedurecanbeused,asgiven–6-2–RecommendationsforLoadsonBuildingsinA6.11.(10)Theincreaseofwind-inducedvibrationcausedbyneighboringbuildingsshallbeconsideredfromA6.12.(11)Theresponseaccelerationforcheckingthehabitabilityofabuildingagainstwind-inducedvibrationshallbeevaluatedfromA6.10.Forthisevaluation,the1-year-reccurencewindspeedcanbeobtainedfromA6.13.(12)Whenthewindloadshieldingeffectsbysurroundingtopographiesorbuildingsareconsidered,thefuturechangesshallbeconfirmed,andtheshieldingeffectshallbeinvestigatedbyappropriatewindtunnelstudyorothersuitableverificationmethods.6.1.3Buildingsforwhichparticularwindloadorwindinducedvibrationistakenintoaccount(1)Buildingsforwhichhorizontalwindloadsonstructuralframesinacross-windandtorsionaldirectionsaretakenintoaccountForthebuildingsthatsatisfythefollowingcriteria,windloadintheacross-winddirectionasdefinedinA6.4andwindloadinthetorsionaldirectionasdefinedinA6.5shallbechecked.3≥BDH(6.1)whereH(m):referenceheightasdefinedin6.1.2(4)B(m):buildingbreadthD(m):buildingdepth(2)VortexresonanceandaeroelasticinstabilityForbuildingsthatsatisfythefollowingcriteria,vortex-inducedvibrationandaeroelasticinstabilityshallbecheckedbytheappropriatewindtunneltestsandsoon.Forbuildingswithcircularsection,thewindloadisprescribedinA6.7.1)Forbuildingswithrectangularsection4≥BDHand⎟⎟⎠⎞⎜⎜⎝⎛≥≥*TcrTH*LcrLH83.083.0UBDfUorUBDfU(6.2)whereHU(m/s):designwindspeedasdefinedinA6.1.2.(winddirectionalityfactor1D=K)*LcrU:non-dimensionalcriticalwindspeedforaeroelasticinstabilityinacross-winddirectioncalculatedfromTable6.1*TcrU:non-dimensionalcriticalwindspeedforaeroelasticinstabilityintorsionaldirectioncalculatedfromTable6.2TL,ff(Hz):naturalfrequencyforfirstmodeinacross-windandtorsionaldirections2)Forbuildingswithcircularcross-section7m≥DHand2.4mLH≥DfU(6.3)CHAPTER6WINDLOADS–6-3–wheremD(m):buildingdiameteratheight3/2HTable6.1Non-dimensionalcriticalwindspeedforaeroelasticinstabilityinacross-winddirection*LcrUFlatterraincategoriesSideratioBD/ScrutonnumberLδNote)Criticalspeed*LcrUI,II≤BD/0.8Lδ≤0.716LδLδ0.7110.8≤BD/1.5all1.2Lδ+7.31.5≤BD/2.5Lδ≤0.22.30.2Lδ≤0.812Lδ0.815LδBD/2.5Lδ≤0.43.7Lδ0.4notnecessarytoevaluateIII,IV,V≤BD/0.8all4.5Lδ+6.70.8≤BD/1.2all0.7Lδ+8.8BD/1.2all11Note)Lδisthemassdampingparameterdefinedas)3/(LLBDHMρζδ=,whereLζisthedampingratioforthefirstmodeintheacross-winddirection,M(kg)isthetotalbuildingmass,ρ(1.22kg/m3)istheairdensity.Table6.2Non-dimensionalcriticalwindspeedforaeroelasticinstabilityintorsionaldirection*TcrUSideratioBD/ScrutonnumberTδNote)Criticalspeed*TcrUBD/≤1.5Tδ≤0.0520.05Tδ≤0.111Tδ0.1notnecessarytoevaluate1.5BD/≤2.5Tδ≤0.0520.05Tδ≤0.154+8TδTδ0.158.6+7.4Tδ2.5BD/≤5Tδ≤0.052Tδ0.055+10.5TδNote)Tδisthemassdampingparameterdefinedas)36/()(2222TTHDBDBMρζδ+=,whereTζisthedampin