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1、我国预应力混凝土结构当前面临的问题和对策ProblemsandCountermeasuresofprestressedconcretestructuresinChina1PrefacePrestressedconcreteistherapiddevelopmentofWesternEuropeaftertheSecondWorldWar,whichurgentlycallsfortherestorationofwarwounds.Inthepasthalfcentury,greatprogresshasbeenma
2、deintheory,materials,technologyandvariousapplicationsincivilengineering.Especiallywiththegradualmaturityoftheconceptofpartiallyprestressedconcrete,ithasbrokentherestrictionthatconcretecannotbesubjectedtotensionandcracking,thusgreatlyexpandingitsscopeofapplicat
3、ion.Atpresent,theprestressedconcretestructurematerialhasbecomeoneofthemaindomesticandforeigncivilengineering,andthetechnologyhasbeenappliedtoexpandprestressedsteel,brick,stone,woodandothermaterials,andusedinvariousprocessingstructuredesign,ShiGongzhong,usingco
4、nventionaltechniquestosolvedifficultproblems.TheprestressedconcreteinChinastartedabout10yearslaterthanWesternEurope,butthedemandforlarge-scaleconstructionisnotonlyrapid,butalsohuge.Accordingtoincompletestatisticsin1995:theconstructionofprecastprestressedconcre
5、temembersofvariousindustrialworkshopatotalareaof1billionsquaremeters,theconstructionofurbanandruralresidentialhousingmorethan3billionsquaremeters,builtwithinthe40mspanrailwaybridge30000holes,thenewhighwayandcitybridge,acrossmorethan20maccountedformorethan85%.T
6、heseachievementshavecontributedgreatlytothebasicconstructionofChina'spastfiveyearplan,andhavesavedagreatdealofsteelandwoodforthecountry.Sincethereformandopeningtotheoutsideworld,theproductionofhighstrengthsteelinChinahasbeenimproved,whichhascreatedconditionsfo
7、rthedevelopmentofhighlyefficientprestressedconcreteandthepursuitofinternationalstandards.Inthepasttenyears,greatprogresshasbeenmadeintheapplicationofhighefficiencyprestressedconcrete.Varioustypesofbridgestructure,spanandconstructionmethodshavemadegreatprogress
8、.Precastprestressedconcretesimplesupportspanrailwaybridge:theeconomyhasexpandedto40mhighwayandcitybridge;expandedto50m;themaximumof270mprestressedconcretecontinuousframebridge;long