外文翻译---预应力混凝土

《外文翻译---预应力混凝土》由会员上传分享，免费在线阅读，更多相关内容在工程资料-天天文库。

1、外文翻译INTRODUCTIONTOPRESTRESSCONCRETEBasicConceptsofPrestressingPrestressingconcreteisbasicallyconcreteinwhichinternalstressesofsuitablemagnitudeanddistributionareintroductionsothatthestressesresultingfromexternalloadsareconteractedtoadesireddegree.inreinforcedconcretemembers,theprestressiscommo

2、nlyintroducedbytensioningthesteelreinforcement.Theearliestexamplesofwoodenbarrelconstructionbyforce-fittingofmetaltyresonwoodenwheelsindicatethattheartofprestressinghasbeenpracticedfromancienttimes.thetensilestrengthofplainconcreteisonlyafractionofitscompressivestrengthandtheproblemofitbeingde

3、ficientintensilestrengthappearstohavebeenthedrivingfactorinthedevelopmentofthecompositematerialknownas“reinforcedconcrete”.Thedevelopmentofearlycracksinreinforcedconcreteduetonon-compatibilityinthestrainsofsteelandconcretewasperhapsthestartingpointforthedevelopmentofanewmateriallike“presstress

4、edconcrete“.theapplicationofpermanentcompressivestresstoamateriallikeconcrete,whichisstrongincompressionbutweakintension,increasestheapparenttensilestrengthofthatmaterial,becausethesubsequentapplicationoftensilestressmustfirstnullifythecompressiveprestress.in1904Fresyssinetattemptedtosubstitut

5、epermanentlyactingforcesinconcretetoresistthelasticforcesdevelopedunderloadsandthisideawaslaterdevelopedunderthenameof“prestressing”.thesignificantobservationwhichresultedfrompioneeringresearchworkonpretressedconcretewereNeedforHighStrengthandConcrete1.Nessityofusinghighsteelandconcrete.2.Reco

6、gnitionoflosserofprestressduetovariouscauses.heearlyattemptstousemindsteelinprestressedconcretewerenotsuccessfulsincetheworkingstressinmildsteelof120N/MM2moreorlesscompletelylostduetoelasticdeformation,creepandshrinkageofconcrete.Thenomorelossofstressofstressinsteelisgenerallyabout100to240N/MM

7、2anditisapparentthatifthislossofstressistobeasmallportionoftheintitlestress,thestressinstressinsteelintheintitlestagesmustbeveryhigh,about1200to2000N/MM2.therehighstressrangesarepossibleonlywiththeuseofhighstrengthsteel.Highstrengthconc