建筑防火中英文对照外文翻译文献.docx

建筑防火中英文对照外文翻译文献.docx

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建筑防火中英文对照外文翻译文献

中英文对照外文翻译

（文档含英文原文和中文翻译）

外文文献:

DesigningAgainstFireOfBuliding

ABSTRACT:

Thispaperconsidersthedesignofbuildingsforfiresafety.Itisfoundthatfireandtheassoci-atedeffectsonbuildingsissignificantlydifferenttootherformsofloadingsuchasgravityliveloads,windandearthquakesandtheirrespectiveeffectsonthebuildingstructure.Fireeventsarederivedfromthehumanactivitieswithinbuildingsorfromthemalfunctionofmechanicalandelectricalequipmentprovidedwithinbuildingstoachieveaserviceableenvironment.Itisthereforepossibletodirectlyinfluencetherateoffirestartswithinbuildingsbychanginghumanbehaviour,improvedmaintenanceandimproveddesignofmechanicalandelectricalsystems.Furthermore,shouldafiredevelops,itispossibletodirectlyinfluencetheresultingfireseveritybytheincorporationoffiresafetysystemssuchassprinklersandtoprovidemeasureswithinthebuildingtoenablesaferegressfromthebuilding.Theabilitytoinfluencetherateoffirestartsandtheresultingfireseverityisuniquetotheconsiderationoffirewithinbuildingssinceotherloadssuchaswindandearthquakesaredirectlyafunctionofnature.Thepossibleapproachesfordesigningabuildingforfiresafetyarepresentedusinganexampleofamulti-storeybuildingconstructedoverarailwayline.Thedesignofboththetransferstructuresupportingthebuildingovertherailwayandthelevelsabovethetransferstructureareconsideredinthecontextofcurrentregulatoryrequirements.Theprinciplesandassumptionsassoci-atedwithvariousapproachesarediscussed.

1INTRODUCTION

Otherpaperspresentedinthisseriesconsiderthedesignofbuildingsforgravityloads,windandearthquakes.Thedesignofbuildingsagainstsuchloadeffectsistoalargeextentcoveredbyengineeringbasedstandardsreferencedbythebuildingregulations.Thisisnotthecase,tonearlythesameextent,inthecaseoffire.Rather,itisbuildingregulationssuchastheBuildingCodeofAustralia（BCA）thatdirectlyspecifymostoftherequirementsforfiresafetyofbuildingswithreferencebeingmadetoStandardssuchasAS3600orAS4100formethodsfordeterminingthefireresistanceofstructuralelements.

Thepurposeofthispaperistoconsiderthedesignofbuildingsforfiresafetyfromanengineeringperspective（asiscurrentlydoneforotherloadssuchaswindorearthquakes）,whilstatthesametime,puttingsuchapproachesinthecontextofthecurrentregulatoryrequirements.Attheoutset,itneedstobenotedthatdesigningabuildingforfiresafetyisfarmorethansimplyconsideringthebuildingstructureandwhetherithassufficientstructuraladequacy.Thisisbecausefirescanhaveadirectinfluenceonoccupantsviasmokeandheatandcangrowinsizeandseverityunlikeothereffectsimposedonthebuilding.Notwithstandingthesecomments,thefocusofthispaperwillbelargelyondesignissuesassociatedwiththebuildingstructure.

Twosituationsassociatedwithabuildingareusedforthepurposeofdiscussion.Themulti-storeyofficebuildingshowninFigure1issupportedbyatransferstructurethatspansoverasetofrailwaytracks.Itisassumedthatawiderangeofrailtrafficutilisesthesetracksincludingfreightanddiesellocomotives.Thefirstsituationtobeconsideredfromafiresafetyperspectiveisthetransferstructure.ThisistermedSituation1andthekeyquestionsare:

whatleveloffireresistanceisrequiredforthistransferstructureandhowcanthisbedetermined?

Thissituationhasbeenchosensinceitclearlyfallsoutsidethenormalregulatoryscopeofmostbuild-ingregulations.Anengineeringsolution,ratherthanaprescriptiveoneisrequired.Thesecondfiresituation（termedSituation2）correspondstoafirewithintheofficelevelsofthebuildingandiscoveredbybuildingregulations.Thissituationischosenbecauseitwillenableadiscussionofengineeringapproachesandhowtheseinterfacewiththebuildingregulations–sincebothengineeringandprescriptivesolutionsarepossible.

2UNIQUENESSOFFIRE

2.1Introduction

Windandearthquakescanbeconsideredtobe“natural”phenomenaoverwhichdesignershavenocontrolexceptperhapstochoosethelocationofbuildingsmorecarefullyonthebasisofhistoricalrecordsandtodesignbuildingtoresistsufficientlyhighloadsoraccelerationsfortheparticularlocation.Deadandliveloadsinbuildingsaretheresultofgravity.Alloftheseloadsarevariableanditispossible（althoughgenerallyunlikely）thattheloadsmayexceedtheresistanceofthecriticalstructuralmembersresultinginstructuralfailure.

Thenatureandinfluenceoffiresinbuildingsarequitedifferenttothoseassociatedwithother“loads”towhichabuildingmaybesubjectedto.Theessentialdifferencesaredescribedinthefollowingsections.

2.2OriginofFire

Inmostsituations（ignoringbushfires）,fireoriginatesfromhumanactivitieswithinthebuildingorthemalfunctionofequipmentplacedwithinthebuildingtoprovideaserviceableenvironment.Itfollowsthereforethatitispossibletoinfluencetherateoffirestartsbyinfluencinghumanbehaviour,limitingandmonitoringhumanbehaviourandimprovingthedesignofequipmentanditsmaintenance.Thisisnotthecasefortheusualloadsappliedtoabuilding.

2.3AbilitytoInfluence

Sincewindandearthquakearedirectlyfunctionsofnature,itisnotpossibletoinfluencesucheventstoanyextent.Onehastoanticipatethemanddesignaccordingly.Itmaybepossibletoinfluencethelevelofliveloadinabuildingbyconductingauditsandplacingrestrictionsoncontents.However,inthecaseofafirestart,therearemanyfactorsthatcanbebroughttobeartoinfluencetheultimatesizeofthefireanditseffectwithinthebuilding.Itisknownthatoccupantswithinabuildingwilloftendetectafireanddealwithitbeforeitreachesasig-nificantsize.Itisestimatedthatlessthanonefireinfive（Favre,1996）resultsinacalltothefirebrigadeandforfiresreportedtothefirebrigade,themajoritywillbelimitedtotheroomoffireorigin.Inoc-cupiedspaces,olfactorycues（smell）providepowerfulevidenceofthepresenceofevenasmallfire.Theadditionofafunctionalsmokedetectionsystemwillfurtherimprovethelikelihoodofdetectionandofactionbeingtakenbytheoccupants.

Firefightingequipment,suchasextinguishersandhosereels,isgenerallyprovidedwithinbuildingsfortheuseofoccupantsandmanyorganisationsprovidetrainingforstaffinrespectoftheuseofsuchequipment.

Thegrowthofafirecanalsobelimitedbyautomaticextinguishingsystemssuchassprinklers,whichcanbedesignedtohavehighlevelsofeffectiveness.Firescanalsobelimitedbythefirebrigadedependingonthesizeandlocationofthefireatthetimeofarrival.

2.4EffectsofFire

Thestructuralelementsinthevicinityofthefirewillexperiencetheeffectsofheat.Thetemperatureswithinthestructuralelementswillincreasewithtimeofexposuretothefire,therateoftemperaturerisebeingdictatedbythethermalresistanceofthestructuralelementandtheseverityofthefire.Theincreaseintemperatureswithinamemberwillresultinboththermalexpansionand,eventually,areductioninthestructuralresistanceofthemember.Differentialthermalexpansionwillleadtobowingofamember.Significantaxialexpansionwillbeaccommodatedinsteelmembersbyeitheroverallorlocalbucklingoryieldingoflocal-isedregions.Theseeffectswillbedetrimentalforcolumnsbutforbeamsformingpartofafloorsystemmayassistinthedevelopmentofotherloadresistingmechanisms（seeSection4.3.5）.

Withtheexceptionofthedevelopmentofforcesduetorestraintofthermalexpansion,firedoesnotimposeloadsonthestructurebutratherreducesstiffnessandstrength.Sucheffectsarenotinstantaneousbutareafunctionoftimeandthisisdifferenttotheeffectsofloadssuchasearthquakeandwindthataremoreorlessinstantaneous.

Heatingeffectsassociatedwithafirewillnotbesignificantortherateoflossofcapacitywillbeslowedif:

（a）thefireisextinguished（e.g.aneffectivesprinklersystem）

（b）thefireisofinsufficientseverity–insufficientfuel,and/or

（c）thestructuralelementshavesufficientthermalmassand/orinsulationtoslowtheriseininternaltemperature

Fireprotectionmeasuressuchasprovidingsufficientaxisdistanceanddimensionsforconcreteelements,andsufficientinsulationthicknessforsteelelementsareexamplesof（c）.TheseareillustratedinFigure2.

Thetwosituationsdescribedintheintroductionarenowconsidered.

3FIREWITHINBUILDINGS

3.1FireSafetyConsiderations

Theimplicationsoffirewithintheoccupiedpartsoftheofficebuilding（Figure1）（Situation2）arenowconsidered.Firestatisticsforofficebuildingsshowthataboutonefatalityisexpectedinanofficebuildingforevery1000firesreportedtothefirebrigade.Thisisanorderofmagnitudelessthanthefatalityrateassociatedwithapartmentbuildings.Morethantwothirdsoffiresoccurduringoccupiedhoursandthisisduetothegreaterhumanactivityandthegreateruseofserviceswithinthebuilding.Itistwiceaslikelythatafirethatcommencesoutofnormalworkinghourswillextendbeyondtheenclosureoffireorigin.

Arelativelysmallfirecangeneratelargequantitiesofsmokewithintheflooroffireorigin.Ifthefloorisofopen-planconstructionwithfewpartitions,thepresenceofafireduringnormaloccupiedhoursisalmostcertaintobedetectedthroughtheobservationofsmokeonthefloor.Thepresenceoffullheightpartitionsacrossthe