土木工程钢结构和钢筋混凝土结构外文文献翻译.docx

土木工程钢结构和钢筋混凝土结构外文文献翻译.docx

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土木工程钢结构和钢筋混凝土结构外文文献翻译

文献信息：

文献标题：

Recentresearchanddesigndevelopmentsinsteelandcompositesteel–concretestructuresinUSA（近期美国在钢结构和钢筋混凝土结构研究和设计方面的发展）

国外作者：

TheodoreV.Galambos

文献出处：

《JournalofConstructionalSteelResearch》,2000,55（1-3）:

289-303

字数统计：

英文4718单词，23395字符；中文7671汉字

外文文献：

Recentresearchanddesigndevelopmentsinsteelandcompositesteel–concretestructuresinUSA

AbstractAbriefreviewofthestatusofstructuralsteelresearchintheUSattheendoftheTwentiethCenturyispresentedinthispapertoshowthatwhilemanyproblemsarebeingsolved,therearenewandchallengingproblemsremaining.Thechiefimpetusforcontinuedresearchisthatprovidedbynaturaldisasters,suchasearthquakes,tropicalstorms,tornadoesandfloodsoccurringindenselypopulatedurbanareas.Newmaterialsandnewexperimentalandcomputationaltechnologiesalsogiverisetonewandexcitingresearchproblems.

Keywords:

Bridges;Buildings;Design;Research;Steelstructures;UnitedStatesofAmerica;Seismicbehavior;High-performancematerials

1.Introduction

ThepurposeofthispaperistogiveabriefoverviewofthecurrentdevelopmentsinstructuralsteelresearchintheUS,andofthefuturedirectionsthatthestructuralsteelengineeringresearchmaytakeinthecomingCentury.Thedrivingforcesofresearchinthisfieldarethefollowing:

•newconstructionmethodsandconstructionproducts

•newmaterials

•economicconsiderations

•naturaldisasters

Threeofthesemotivationsarecommontoallengineeringdevelopments,notjusttostructuralengineering.However,theimpetusduetonaturaldisastersisuniquetoourfield.RecentmajornaturaldisastersintheUS,suchastheNorthridgeearthquakeinCaliforniaandhurricaneAndrewinFlorida,havespurredmuchofthecurrentresearchactivity.

Thepresentationhereisofnecessityincomplete,becausetheauthorisnotawareofallresearchgoingoneverywhereinthecountryandthereisnotenoughspaceinthispresentation.Theoverviewismeanttogiveageneralflavoroftheresearchactivities,andtoshowthatasignificanteffortisgoingonintheUS.Thefollowingisalistof10majortopicsinsteelresearch:

1.LimitStatesDesignforbridges

2.Monitoringofstructuralperformanceinthefield

3.Designofseismicallyresistantconnections

4.Curvedgirderbridges

5.Compositecolumnswithhigh-performanceconcrete

6.Buildingframeswithsemi-rigidjoints

7.“AdvancedStructuralAnalysis”forbuildings

8.Repairandretrofitofstructures

9.Steelstructureswithhigh-performancesteels

10.Cold-formedsteelstructures

Thenextpartsofthispaperwillgivebriefdiscussionsonsomeofthesetopics.Severaltopicswillthenbeelaboratedinmoredetail.Thepaperwillconcludewithalooktowardthefutureofstructuralsteelresearch.

2.Researchonsteelbridges

TheAmericanAssociationofStateTransportationandHighwayOfficials（AASHTO）istheauthoritythatpromulgatesdesignstandardsforbridgesintheUS.In1994ithasissuedanewdesignspecificationwhichisaLimitStatesDesignstandardthatisbasedontheprinciplesofreliabilitytheory.Agreatdealofworkwentintothedevelopmentofthiscodeinthepastdecade,especiallyoncalibrationandontheprobabilisticevaluationofthepreviousspecification.Thecodeisnowbeingimplementedinthedesignoffice,togetherwiththeintroductionoftheSystemeInternationaleunits.Manyquestionsremainopenaboutthenewmethodofdesign,andtherearemanynewprojectsthatdealwiththereliabilitystudiesofthebridgeasasystem.Onesuchcurrentprojectisastudytodevelopprobabilisticmodels,loadfactors,andrationalload-combinationrulesforthecombinedeffectsofliveloadandwind;live-loadandearthquake;live-load,windandshipcollision;andshipcollision,wind,andscour.Therearealsomanyfieldmeasurementsofbridgebehavior,usingmoderntoolsofinspectionandmonitoringsuchasacousticemissiontechniquesandothermeansofnon-destructiveevaluation.Suchfieldworknecessitatesparallelstudiesinthelaboratory,andtheevolutionofevermoresophisticatedhigh-technologydatatransmissionmethods.

Americahasanagingsteelbridgepopulationandmanyproblemsarisefromfatigueandcorrosion.Fatiguestudiesonfull-scalecomponentsoftheWilliamsburgBridgeinNewYorkhaverecentlybeencompletedatLehighUniversity.AprobabilisticAASHTObridgeevaluationregulationhasbeenineffectsince1989,anditisemployedtoassessthefutureusefullifeofstructuresusingrationalmethodsthatincludefieldobservationandmeasurementtogetherwithprobabilisticanalysis.Suchanactivityalsofostersadditionalresearchbecausemanyissuesarestillunresolved.Onesuchareaisthestudyoftheshakedownofshearconnectorsincompositebridges.ThisworkhasbeenrecentlycompletedattheUniversityofMissouri.

Inadditiontofatigueandcorrosion,themajordangertobridgesisthepossibilityofearthquakeinduceddamage.Thisalsohasspawnedmanyresearchprojectsontherepairandretrofitofsteelsuperstructuresandthesupportingconcretepiers.Manybridgesinthecountryarebeingstrengthenedforearthquakeresistance.Oneareathatisreceivingmuchresearchattentionisthestrengtheningofconcretepiersby“jacketing”thembysheetsofhigh-performancereinforcedplastic.

Thepreviouslydescribedresearchdealsmainlywiththebehaviorofexistingstructuresandthedesignofnewbridges.However,thereisalsoavigorousactivityonnovelbridgesystems.Thisresearchiscenteredontheapplicationofhigh-performancesteelsforthedesignofinnovativeplateandbox-girderbridges,suchascorrugatedwebs,combinationsofopenandclosedshapes,andlongerspansfortrussbridges.Itshouldbementionedherethat,inadditiontoworkonsteelbridges,thereisalsoveryactiveresearchgoingoninthestudyofthebehaviorofprestressedconcretegirdersmadefromveryhighstrengthconcrete.Theperformanceanddesignofsmallerbridgesusingpultrudedhigh-performanceplasticcompositemembersisalsobeingstudiedextensivelyatpresent.Newcontinuousbridgesystemswithsteelconcretecompositesegmentsinboththepositivemomentandthenegativemomentregionsarebeingconsidered.Severalresearchershavedevelopedstrongcapabilitiestomodelthethree-dimensionalnon-linearbehaviorofindividualplategirders,andmanystudiesarebeingperformedonthebucklingandpost-bucklingcharacteristicsofsuchstructures.Companionexperimentalstudiesarealsomade,especiallyonmembersbuiltfromhigh-performancesteels.Afull-scalebridgeofsuchsteelhasbeendesigned,andwillsoonbeconstructedandthentestedundertrafficloading.Researcheffortsarealsounderwayonthestudyofthefatigueoflargeexpansionjointelementsandonthefatigueofhighwaysignstructures.

Thefinalsubjecttobementionedistheresurgenceofstudiesofcompositesteelconcretehorizontallycurvedsteelgirderbridges.AjustcompletedprojectattheUniversityofMinnesotamonitoredthestressesandthedeflectionsinaskewedandcurvedbridgeduringallphasesofconstruction,startingfromthefabricationyardtothecompletedbridge.Excellentcorrelationwasfoundtoexistbetweenthemeasuredstressesanddeformationsandthecalculatedvalues.Thestressesanddeflectionsduringconstructionwerefoundtoberelativelysmall,thatis,theconstructionprocessdidnotcauseseveretraumatothesystem.Thebridgehasnowbeentestedunderserviceloading,usingfullyloadedgraveltrucks,fortwoyears,anditwillcontinuetobestudiedforfurtheryearstomeasurechangesinperformanceunderserviceovertime.AmajortestingprojectisbeingconductedattheFederalHighwayAdministrationlaboratoryinWashington,DC,whereahalf-scalecurvedcompositegirderbridgeiscurrentlybeingtestedtodetermineitslimitstates.Thetest-bridgewasdesignedtoactasitsowntest-frame,wherevariousportionscanbereplacedaftertesting.Multipleflexuretests,sheartests,andtestsundercombinedbendingandshear,arethusperformedwithrealisticend-conditionsandrestraints.Theexperimentsarealsomodeledbyfiniteelementanalysistocheckconformancebetweenrealityandprediction.Finallydesignstandardswillbeevolvedfromtheknowledgegained.ThislastprojectisthelargestbridgeresearchprojectintheUSAatthepresenttime.

Fromthediscussionaboveitcanbeseenthateventhoughthereisnolargeexpansionofthenation’shighwayandrailroadsystem,thereisextensiveworkgoingoninbridgeresearch.Themajorchallengefacingboththeresearcherandthetransportationengineeristhemaintenanceofahealthybutagingsystem,seeingtoitsgradualreplacementwhilekeepingitsafeandserviceable.

3.Researchonsteelmembersandframes

Therearemanyresearchstudiesonthestrengthandbehaviorofsteelbuildingstructures.Themostimportantofthesehavetodowiththebehavioranddesignofsteelstructuresundersevereseismicevents.Thistopicwillbediscussedlaterinthispaper.Themostsignificanttrendsofthenon-seismicresearcharethefollowing:

•“Advanced”methodsofstructuralanalysisanddesignareactivelystudiedatmanyUniversities,notablyatCornell,Purdue,Stanford,andGeorgiaTechUniversities.Suchanalysismethodsaremeanttodeterminetheload-deformationbehaviorofframesuptoandbeyondfailure,includinginelasticbehavior,forceredistribution,plastichingeformation,second-ordereffectsandframeinstability.Whenthesemethodsarefullyoperational,thestructurewillnothavetoundergoamembercheck,becausethefiniteelementanalysisoftheframeautomaticallyperformsthisjob.Inadditiontotheres