美国规定的混凝土抗压强度与中国混凝土强度等级的比较

:1006)2610(2008)03)0065)03美国规定的混凝土抗压强度与中国混凝土强度等级的比较冯兴中(中国水电顾问集团西北勘测设计研究院,西安710065):fccfcu,k,,fcc,fcc=3000psi0.8C25;,0.85fcc;90%fcc95%0.8C25:;;;;fcc;fcu,k;;:TU37;TU311.2:AComparisonofASTMconcretecompressivestrengthandChina'sconcretestrengthgradeFENGXing-zhong(NorthwestHydroConsultingEngineers,Xia'n710065,China)Abstract:ThecomparisonofASTMconcretecompressivestrengthfccandChinas'concretestrengthfcu,kgradeisthemostbasiccomponentsincertainconceptcomparisons.Intermsofconcretestrength,fccequalstoChinas'concretestrengthgrade,and0.8C25concretestrengthgradeisclosetofcc=3000ps.iIncomparisonofstrengthreductionrequiredbyguaranteedrate,0.85fcccorrespondstoChinas'concretestandardstrength.Thefccof90%guaranteedrateinASTMisalittlegreaterthan0.8C25of95%guaranteedrateinChina.KeyWords:concrete;compressivestrength;standardstrength;strengthgrade;fcc;fcu,k;China;ASTM:2008-01-23:(1955-),,,,.,,,,,fccfcu,k,,,fcc,fcc=3000psi(/)21MPa;fcu,k,fcu,k=25MPaC25;fccC10~C60?fccfcu,k1fccfy[1],b@h=12in@24in;fcc=3ksi(/),B1=0.85;fy=60ks,i258in,As=1.58in2;U=0.9;,a:T=Asfy=1.58@60=94.8();C=B1fccba=0.85@3@12a=30.6a;,T=C,Asfy=B1fcba;a=94.830.6=3.1in;65西北水电#2008年#第3期M=U(Asfy)(h0-aA2)=0.9@94.8@(20.5-3.1A2)=1616.8(#)=185.4kN#mfy,40fy=280MPa[2],Q235(0.05)235MPa0.85fcc,2fccfcu,k2.1fcc(1)[3]21:fcr=fcc1-tV:fcr75%,80%85%fcc;tfccV;t=0.88380%,t=1.185%;V()fcc=3000psi,,fcc=3000ps,i85%(t=1.1),V15%,:fcr=fcc1-tV=30001-1.1@0.15=3590psiU25.12MPa2195%t,,t=1.645,fcr95=fcc1-tV=30001-1.645@0.15=3983psiU27.88MPa(1)(2)[4]5.3.2.2:fcc=3000~5000ps,is,fcr=fcc+1200psi,fcc=3000ps,ifcr90=3000+1200=4200psiU29.4MPaACI318fcr90%,fcr90U29.4MPa[3]fcr95U27.88MPa,95%2.2fccª150mm@300mm,150mmfcu,k,,,DL/T5150-2001566.6.4:150mm,(ª150mm@300mm150mm0.8)/210.83205696:Eurocode2(2001)CEB-FIPM(1990)150mm,,ª150mm@300mmfcc150mmfcu,k,:fcc=0.8fcu,k,,,0.8fcc=3000psiU21MPa,21MPa=0.8fcu,k,,fcu,k=21/0.8=26.25MPa,fcc=3000psi0.8C252.3fcu,kDL/T5150-200156G:fP=fm1-tVfP=fm+tR,t=0.84280%,t=1.2890%,t=1.64595%;V;fP,;fm,,25.0MPa,95%,,V=0.15,fP:fp95=fm1-tV=251-1.645@0.15=33.2MPa66冯兴中.美国规定的混凝土抗压强度与中国混凝土强度等级的比较25.0MPa,C25,95%0.80.8@33.2=26.56MPa,fcc=3000psi95%fcr95=3983psiU27.88MPa,(1),:fcc=3000psi0.8C253,28d95%3.1(1)fcc90%,:fcc=fcr-1.345Ss(2):fcr,50%;Ss,-1.345Ss0.0901,+1.345Ss0.9099,P90:P90=50%+0.9099-0.09012U91%(2)GB50010-200295%,:fcu,k=ufcu-1.645Rfcu,ufcu,50%,Rfcu,-1.645Rfcu0.05,+1.645Rfcu0.95,P95:P95=50%+0.95-0.052=95%3.295%(1),90%fcc=3000psifcr=3983ps,i(2):Ss=3983-30001.34=730psifc95c=fcr-1.645@730=2782psiU19.48MPafcc0.85,0.85fcc,fcc,0.85fc95c=0.85@19.48=16.55MPa(2),fck=0.88Ac1Ac2fcu,k:0.88,,0.85;Ac1,C50,Ac1=0.76,,,,0.76(0.8);Ac2,C40,Ac2=1.0C25,fck=0.88@0.76@1.0@25=16.7MPa,fc95c=0.85@19.48=16.55MPa0.85fc90c0.85fc95c,0.85fc90cC254fccfy,,;,fcc;fcc=3000psi0.8C25;,fcc=3000ps,i0.85fc95cC25;,,fcc,,,:[1].()[M].:,2003.[2]ArthurH.Nilson,eta.lDesignofconcreteStructures(13)[M].:,2007.[3]U.S.DepartmentoftheInteriorBureauofReclamation.ConcreteManual(8thEdition)[A].AWaterResourcesTechnicalPublica-tion[C].U.S.,1989.[4]ACI.(ACI318-05)[M].:,2007.67西北水电#2008年#第3期