专业英语论文.docx
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专业英语论文.docx
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专业英语论文
成绩
徐州工程学院
09级房建(3)班课程考试试卷
考试科目专业英语
考试时间2011.12.15
学生姓名张伟
所在院系土木学院
任课教师刘志勇
徐州工程学院印制
RULESOFCONSTRUCTl0N
Asmasonryisacraft,therearecertainrulesforachievingahigh-qualityfinish.Themostimportantaimsare:
_Optimizingtheloadbearingandresistancepropertiesoftheconstruction
_Minimizinglossofmaterial
_Speedingupthebuildingprocess
_Executingadesignthatdoesjusticetomaterialanduse
Theserulesformatheoreticalbasisforthewallstructuresgiveninthethirdchapter.Theyshowtheprinciplesandmethodsforcreatingmasonryfromitscomponents,thepreferreddimensions,andhowtoformconnectionsandaperturescorrectlyforthematerial.Theindividualwallwillbeconsideredfirst.
DIMENSIONSANDMODULES
Oneofthearchitect’smaintaskswhenplanningandconstructingabuildingistocoordinateandcombinethevariousstructuralandcraftservices.Shellconstruction(walls,columns,floorsetc.)andfinishing(win-dows,doors,wallandfloorcoveringsetc.)havetobematchedinordertobuildefficiently.Theactualbuildingprocess,aswellasplanningandfinishing,aresimplifiedbyrepeatingelementsandsizes.However,fixinggriddimensionsisproblematicalformasonry,asitisimpossibletoworkwiththedimensionsofthebricksalone,sincewemustallowforthemortarjointsbetweenthebricksaswell.Here,asimpledeviceisusedtodecidewhenthejointmustbeaddedtoawalllengthornot:
thedistinctionbetweenspecifiedandnominaldimensions.-
Thespecifieddimensionisthebasictheoreticalmeasurement,thegridorthemodulemultipliedtoputtogetherthewholemasonryconstrucfionsystem.Thenominaldimension,however,isthedimensionthatisactuallyexecutedandenteredontheconstructiondrawing.Thisdistinctioncanbeusedtosystematizeconstructiontypeswithjoints,andparticularlymasonryconstructions.
Althoughthenominalandspecifieddimensionsareidenticalwhenbuildingwithoutjoints,theyaretreatedasfollowsinconstructionforbuildingtypeswithjoints:
Thespecifieddimensionconsistsofthenominaldimensionexecutedandthecorrespondingjoint,i.e:
brickdimension+joint
Conversely,thenominaldimensionisthebrickdimensionalone,withoutjoint.
Ifyounowimagineamasonrywallwithwindowaperturesandtransversewalls.
youwilveryquicklyrealizethattherearedifferentdimensionsforthewallwidth,apertureandprojectionsbecauseofthemortarjoints.
Theexternaldimensionisthewallthickness.Onejointmustalwaysbesubtractedfromthespecifieddimensionasthereisalwaysonejointmissing,regardlessofthenumberofbricks.
Externaldemission(E)=specifieddimension-joint.
Theinteriordimensionofanaperturealwayscontainsanadditionaljoint.
Apeturedimension(A)=specifieddimension+joint
Theprojectiondimensionmeasuresthepieceofwallbetweenopeningandwallorwallprojections.Here,themissingjointintheexternaldimensionandtheadditionaljointintheaperturedimensionsbalanceeachotherout.
Projectiondimension(A)=specifieddimension
UNITDIMENTINSANDDESIGNATIONS
Thesehithertotheoreticaldefinitionshaveleftopenthequestionofactualdimensions,whichareindependentofthebrickandjointsizeschosen.Thesesizescanvary,andhaveledtodifferentstandardsindifferentcountries,accordingtolocaltraditions.
InGermany,masonryisbasedalmostexclusivelyontheoctametricsystem,whichusesaneighthofametre=12.5cmasspecifieddimension.Thestandardbrick,So-called“normalformat”,measures24*11*7.1cm(nominaldimensions).Whenthejointsizesforthehorizontalcoursejointsareadded,thisgivesspecifieddimensionsof25*12.5*8.33cm=,multiplesofwhichproduceametre.
Jointsizescanalsovary,withoutchangingthesystem.Newmanufacturingtechnologyandtheneedtomeetthegreater-than-everdemandsonmasonryforheatandsoundinsulation,andintermsofloadbearingcapacity,meanthatmasonrytechniqueisnolongerbasedonthecentimeterjoint.Modernmanufacturedblocksarefinishedtosuchlowtolerancesthatjointsneedbeonlyafewmillimetresthick.
However,tomaintaintheusualspecifieddimensions,theunitdimensionshavebeenadaptedtoensurethattheoveralldimensionsstillfitinwiththesystem:
Forexample:
Traditional:
Germannormalformatbrick24cm+1cmjoint=25cm
Moderntechnique:
manufacturedblack24.7cm+3mmjoint=25cm
Smallformatsarealsodistinguished:
L*W*H=24*11.5*7.1cm-normalformat(NF)
24*11.5*5.2CM-thinformat(DF)
Largerbricksaremadeupofseveralthinformatsasabasicmodulewiththecorrespondingjoints,andarethusdefinedas5DF,forexample.
Examplesfordimensionsintheoctametricsystem:
Specifieddimensions:
12.5cm;25cm;37.5cm;50cm...100cmetc.
Nominaldimensions:
11.5cm;24cm;36.5cm;49cm...99cmetc.
Apeturedimensions:
51cm;1.01m;1.26metc.
Projectiondimensions:
12.5cm;25cm;1.00metc.
Whenbricksarecut,alwaysremembertosubtractajoint:
3/4brick=specifieddimension/4*3-joint=6.25cm*3-1cm=17.75cm.
Cutunitsarespeciallydesignatedinthetopviewonlayingdrawings:
the3/4unit(17.75cm)byadiagonal,the1/2unit(11.5cm)byacross,andthe1/4unit(5.25cm)byapointoracircle.
Theoctametricnumericalvaluesareusedforheightaswell.Toachievethespecifieddimensionheight(25cm,50cm,1metc.),thehorizontalmortarjointsserveasaheightlevelingcourse,andthusmeasurebetween1.05and1.22cm.
BRICKCOURSES
Theindividualrowsinamasonrystructurearecalledcourses.Adistinctionismadeaccordingtotherunofthebricks:
Stretchercourse:
bricksarelaidparallelwiththeaxisofthewall.
Headercourse:
bricksarelaidtransverselytothewallaxis.
Brick-on-edgecourse:
bricksstandedgewiseontheirnarrowsidesasanuprightheadercourse
Sodiercourse:
bricksstandedgewiseontheirnarrowsidesasanuprightheadercourse.
Whilethestretcherandheadercoursesarecombinedwitheachotherindifferentwaysasbonds,theedgeandsoldiercourseswiththeirlargerheadjointsoffergreaterbondstrengthbetweenthebricksandbetterpressuredispersal,astheydonotbreakaseasilyashorizontalbrick.Theyarethereforeusedforlintels,seatingsandcornices.
MASONRYBONDS
TOproducehigh-qualitymasonrywithagoodloadbearingcapacityfrombricksandmortortherearecertaincraftrulesthatmustbefollowedwhenbricksandmortartherearecertaincraftrulesthatmustbefollowedwhenlanyingbricks-theebondrules.Thererulesdistinguishbetweenfourso-calledschoolbonds-thosemostcommonlytaught-accordingtothesequenceinwhichthebrickcoursesarelaidononeanother,andthewaytheyareoffsetfromeachother,
Someofthebondrulesaregeneral,andgiveusthefirsttwoschoolbonds.
Rules:
_Allthecoursesmustbelaidhorizontally.
_Thebrickheightshouldnotbegreaterthanthebrickwidth.
_Onlybricksofthesanmeheightshouldbeusedinasinglecourse(onlyatwallendscantherebeexceptionsineverysecondcourse).
_Thelargestpossiblenumberofwholebricksshouldbeused.
_Theoffsetbetweenthecourseisatleast1/4bricklengthforallperpends.
Thebrickoffsetiscrucialforthewall’sloadbearingcapacity.Thegreatertheoffset,i.e.themoreshallowtherackingbackofthebricks,thegreatertheresistancetolongitudinalcracks.
Instetcherbond,allcoursesinthemasonryaremadeupofstretchercoursesoffsetbythelengthof1/2brick.Asthisbonddoesnotpermitanbrickthick,e.g.forinternalwalls,stretcherbondoffersgoodcompressiveandtensilestrengthbecauseofthelargerbrickoffset.Itisalsopossibletouseanoffsetof1/3or1/4ofabricklength,butthisentailssomelossofloadbearingcapacity.
Inheaderbond,allthecourseconsistofheadercoursesoffsetbythelengthof1/4brick.Thisbondcanonlybeusedforone-brickwalls.Becauseofthelowoverlapthebondhaslessloadbearingcapacityandinclinestodiagonalcracksbecauseofthesteepracking.Itishoweverparticularlysuitablefornarrowmasonryradii.
Combiningthesebondsandfollowingtwomorerulesgivesthelasttwocommonlytaughtbonds.
Rules:
_Stretcherandheadercoursesalternate.
_Onestretchercoursebeginswitha3/4brick(forthickwalls,withcorrespondinglymore3/4bricks).
Englishbondconsistofalternatecoursesofstretchersandheaders.Theoffsetis1/4brick.Thisproducesusefullyshallowrackingby1/4and3/4bricklengthsineachcase.
LikeEnglishbond,Englishcrossbondbeginswithalternatestretcherandheadercourses.Buttheperpendsofstretchercoursesareoffsetagainsteachotherby1/2Brich,sothejointpatternrepeatsonlyeveryfourcourses.Thisbondhasamorevariedjointpattern,butitisalsomoresteeplyrackedandthereforemorepronetodiagonalcracks.
Therearealsosomedecorativebonds,buttheseareonlyofhistoricalorregionalsignificance.ExamplesaredoubleFlemishbond,YorkshirebondandFlemishbond.
Itisalsopossibletoachievealateraloffsetwithinthewall,andsotoconstructwallswithathicknessgreaterthanonebrick,byalternatingstretcherandheadercourses.
Additionalrulesapplyhere:
_Onlyheadershouldbeusedifpossibleforwidewalls.
_Perpendsshouldalsobeatleast1/4bricklengthasthecoursesrisefortheintermediatejointsaswell(perpendsinsidethewall).
_Theoffsetmustbemaintainedlongitudinallyandhorizontally.
REGULARCONSTRUCTIONS
Forcorners,niches,projectionsandcolumns,therearespecialpointsofdetailcoveredbythebondrules.
Rules:
_Thestretchercoursesrunthroughatcorners,junctionsandjoints;theheadercoursesabut.
_Parallelwallsshouldhavethesamesequenceofcourses.
_Onlyoneperpendineachcourseshouldstartfromaninsidecorner.
_Windowsanddo
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