简介:Theseismicperformanceoffourshortconcretecolumnswasinvestigatedunderlowcycleandrepeatedloads,includingthefailurecharacteristics,hystereticbehavior,rigiditydegeneracyandsteel-barstress.Theinfluencesofreinforcementstrength,stirrupratioandshearspanratiowerealsocompared.Testresultsrevealthattherestrictioneffectofstirrupscanimprovethepeakstress,sothebearingcapacityofspecimencanbeimproved;forthehigh-strengthshortconcretecolumnwithhigh-strengthstirrups,itwasmorereasonabletouseultimatedisplacementangletoreflecttheductilityofthespecimen,andtheyieldstrengthofhigh-strengthstirrupsshouldbedevaluedwhencalculatingthestirrupcharacteristicvalue;theseismicperformanceofshortcolumnwouldbeimprovedwiththeincreaseofvolume–stirrupratioandshearspanratio;thehigh-strengthstirrupsandhigh-strengthlongitudinalreinforcementsdidnotyieldwhentheloadactingonthespecimenreachedthepeakvalue,whichbroughtadequatesafetystocktotheseshortcolumns.
简介:Thispaperpresentsaninvestigationonstrengthofcementdeepmixing(CDM)mixture.Fourtypicalworksofoffshoreorland-basedprojectsareintroduced.Withsamplesfromtheseprojectsandlaboratorytests,statisticalanalysisismadeontheincrementlawofthestrengthofcement-soilmixturewithdifferentamountofcement,andstrengthsunderdifferentworkingconditionsarecompared.Itisfoundthattheamountofcementinthecement-soilmixtureiscloselyrelatedtotheunconfinedcompressivestrengthofthemixture.Attheageof90d,theunconfinedcompressivestrengthofthecement-soilmixtureincreasedby0.054Mpa-0.124Mpawitheachcementincreasing10kg/m3inthecement-soilmixture,averagelyincreasedby0.085Mpa,whilethatattheageof120dincreasedby11%incomparison.Thequalityofthecement-soilmixtureshouldbecomprehensivelyevaluatedinaccordancewiththetrimmedaverageofstrength,coefficientofvariationandrockqualitydesignation(RQD)indicatorsofsamplingratio.
简介:In-situvanesheartestisfrequentlyperformedtodetermineshearstrengthforslopestabilityanalysisinTianjinNewHarbor.However,thesoilshearstrengthvarieswiththeshearplaneorientation.Apossiblemeanstoreducetheeffectofdirectionaldependencyofshearstrengthistoconvertthein-situvaneshearstrengthintoundrainedshearstrengthparameters.Amethodofconvertingin-situvaneshearstrengthintoundrainedshearstrengthparametersispresented.Theshearstrengthparametersdeterminedforallofthein-situvaneshearstrengthsaresubjectedtostatisticalregressionanalysistotakeintoconsiderationthepossibleeffectofnon-homogeneityinthesoftclaydeposit.Usingtheregressedshearstrengthparameters,slopestabilityanalysesareperformedforfiveexistingsoilslopes.Theresultsofstabilityanalysesindicatethatthesafetyfactorsobtainedfromtheconvertedparametersreflectthestateoftheslopesanalyzedmuchbetterthanthoseobtainedfromin-situvaneshearstrengthandlaboratoryconsolidated-undrainedandunconsolidated-undrainedstrengthparameters.Itisconcludedthatthepresentedmethsodofdeterminingundrainedshearstrengthparametersforin-situvaneshearstrengthiseffective.
简介:Theearthquake-resistantpropertyofreinforcedconcretemembersdependsontheinteractionbetweenreinforcingbarsandsurroundingconcretethroughbondtoalargedegree.Inthispaperageneralsystemaimedatdealingwiththefailureanalysisofreinforcedconcretecolumnsstrengthenedwithcarbon-fiber-reinforcedplastic(CFRP)sheetsincludingbond-slipoftheanchoredreinforcingbarsatthefootofthecolumnsispresented.Itisbasedontheyielddesigntheorywithamixedmodelingofthestructure,accordingtowhichtheconcretematerialistreatedasaclassicaltwo-dimensionalcontinuum,whereasthelongitudinalreinforcingbarsareregardedasone-dimensionalrodsincludingbond-slipatthefootofthecolumns.InshearreinforcedzonesboththeshearCFRPsheetsandtransversereinforcingbarsareincorporatedintheanalysisthroughahomogenizationprocedureandtheyareonlyintension.Theapproachisthenimplementednumericallybymeansofthefinite-elementformulation.Thenumericalprocedureproducesaccurateestimatesfortheloading-carryingcapacityoftheshearmemberstakenasanillustrativeapplicationbycorrelationwiththeexperimentalresults,sotheproposedapproachisvalid.
简介:Theblastresistanceofstructuresusedinbuildingsneedstobeinvestigatedduetotheincreasedthreatofaterroristattack.ThedamagedonebyCompositionBorPowergeltosteelfibrereinforcedreactivepowderconcrete(SFRPC)panelsandordinaryreinforcedconcrete(RC)panelsofequivalentstaticflexuralstrengthiscompared.A0.5kgchargewasdetonatedatadistanceof0.1mfromthe1.3m×1.0m×0.1m(thick)panels,whichweresimplysupportedandspaning1.3m.Dynamicdisplacementmeasurements,high-speedvideorecordingandvisualexaminationofthepanelsforspallandbreachwereundertaken.TheSFRPCpanelswithstoodthebarechargeblastbetterthanthereinforcedordinaryconcretepanels.Neithertypeofpanelwasbreachedusinga0.5kgcharge.TheRCpanelexhibitedmorespallingwhenCompositionBwasused.UndersuccessiveCompositionBloadingconditions,theRCpanelwasbreached.IncomparisontheSFRPCpanelwasnotbreached.ExposuretofragmentingchargeloadingconditionsconfirmedtheseperformancedifferencesbetweentheSFRPCpanelandthereinforcedordinaryconcretepanel.
简介:许多设计材料随紧张率的增加表明他们的压缩强度的动态改进,它在材料模型被包括了在影响和强风负担下面改进材料和结构的回答的数字模拟的可靠性。设计以hydrostatic-stress-sensitive方式表现的材料的一个范围的动态压缩强度上的紧张率效果被调查。hydrostatic-stress-sensitive材料的压缩强度的动态改进可以包括导致惯性的侧面的监禁效果,这被结束,作为一个non-strain-rate因素,它可以极大地提高这些材料的压缩强度。一些实验公式可以基于紧张率在这些hydrostatic-stress-sensitive材料的压缩强度上完成的动态压力紧张大小在预言上,并且这样过高估计结构的抵抗到影响和强风负担,导致保护的结构的非保守的设计。