土木工程概论电子教案英文版叶志明 CIVIL-E09.ppt

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1、土木工程概论IntroductiontoCivilEngineering第九章　土木工程设计概述Chapter9IntroductiontoDesignofCivilEngineeringIntroductiontoDesignofCivilEngineeringWhatisIntroductiontoDesignofCivilEngineering?Itprovidesthestudentswiththenecessarybackgroundonterminologyusedindesign.Withthischapter,entry-levelstudentsofcivile

2、ngineeringwillbetterunderstandfromtheoutsetlecturesondetailedsubjectareas.Itwillalsoprovebeneficialfornewlyqualifiedprofessionalsandotherswhowantaconciseguidetoeverydaydesignterminology.IntroductiontoDesignofCivilEngineeringClassificationofloads:Accordingtovariationwithtime:Loadswhosemagnitud

3、eisconstant,andnotvaryingwithtimearecalledasstaticloads,andmayvarywithtimearecalledasdynamicloads.Accordingtooccupation:Theloadswhichremainconstantinpositionarecalleddeadloads.Accordingtodistribution:Thedistributionwhereaheavyloaddistributedoverasmallareaiscalledconcentratedload.Theloadwhicha

4、reevenlydistributedoveralargeareaiscalledanuniformlydistributedload.IntroductiontoDesignofCivilEngineeringClassificationofloadsConcentratedLoadUniformlydistributedLoadUniformlyVaryingLoadIntroductiontoDesignofCivilEngineeringInternalforces:Conceptofstress:Conceptofstrain:IntroductiontoDesigno

5、fCivilEngineeringTypesofstressesandstrainsIntroductiontoDesignofCivilEngineeringTRUSSBRIDGELABORATORYBridgesareessentialtoournation'sinfrastructure.Asimplebridgecanbemadebyspanningagapwithplanks.Asthegapbecomeswider,however,theplankswillbegintosagexcessivelyevenundertheweightofaperson.Ifthebr

6、idgeislongerstill,theplanksmaybreak.Whenoneoftheplanks,calledabeam,isloaded,itbendsasshownbelow.Linesaredrawnonthebeamforillustration.IntroductiontoDesignofCivilEngineeringTRUSSBRIDGELABORATORYIntroductiontoDesignofCivilEngineeringTRUSSBRIDGELABORATORYAclose-upviewofashortsegmentofthebeamissh

7、ownbelow.Thetoppartofthebeamisbeingsqueezed(incompression)andthebottompartofthebeamisbeingstretched(intension).Theforceinthebeamactuallychangescontinuouslyfromthetopofthebeamtothebottom.Thatmeansthatinthemiddle(toptobottom),itisneitherincompr