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1、學(xué)兔兔www.xuetutu.com第32卷第6期建筑科學(xué)與工程學(xué)報(bào)VolI32NO.62015年11月Journa1OfArchitectureandCivilEngineeringNOV.2O15文章編號(hào):1673—2049(2015)06—0008—09預(yù)應(yīng)力活性粉末混凝土箱梁抗彎性能試驗(yàn)方志,劉明,鄭輝(湖南大學(xué)土木工程學(xué)院,湖南長沙410082)摘要:為研究預(yù)應(yīng)力活性粉末混凝土(RPC)箱梁的正截面受力性能,進(jìn)行了2片預(yù)應(yīng)力RPC箱梁的抗彎性能試驗(yàn),研究了RPC箱梁的受力變形特征以及頂板橫向預(yù)應(yīng)力對(duì)其抗彎性能的影響。結(jié)果表明:預(yù)應(yīng)力RPC箱梁具有良
2、好的變形能力,其極限變形可超過跨徑的1/50;RPC箱梁正常使用階段的裂縫寬度和短期剛度可參照《纖維混凝土結(jié)構(gòu)技術(shù)規(guī)程》(CECS38:2004)的相應(yīng)公式計(jì)算,其中的鋼纖維影響系數(shù)可分別取為0.4和0.2;RPC箱梁頂板內(nèi)的橫向預(yù)應(yīng)力對(duì)截面抗彎承載力的影響較小,但會(huì)使受壓區(qū)混凝土的應(yīng)變分布更加均勻,從而減弱箱梁頂板受壓的剪力滯效應(yīng)并增加構(gòu)件的延性;試驗(yàn)中對(duì)頂板內(nèi)施加2.95MPa的橫向預(yù)壓應(yīng)力(僅為RPC棱柱體抗壓強(qiáng)度94MPa的3.1)后,可使箱梁受壓翼緣的有效分布寬度增加約1O,構(gòu)件延性指標(biāo)增加約3。試驗(yàn)結(jié)果驗(yàn)證了提出的預(yù)應(yīng)力RPC箱梁正截面抗裂和抗彎
3、承載力的計(jì)算公式。關(guān)鍵詞:活性粉末混凝土;箱梁;抗彎性能;剪力滯效應(yīng);裂縫;變形中圖分類號(hào):U448.35文獻(xiàn)標(biāo)志碼:AExperimentonFlexuralBehaviorsofPrestressedReactivePowderConcreteBOXGirdersFANGZhi,LIUMing,ZHENGHui(CollegeofCivilEngineering,HunanUniversity,Changsha410082,Hunan,China)Abstract:Inordertostudythemechanica1behaviorofprestres
4、sedreactivepowderconcrete(RPC)boxgirders,theflexuralbehaviortestsoftWOprestressedRPCboxgirderswerecarriedout.TheforcecharacteristicofRPCboxgirdersandtheinfluenceoftransverseprestressingforcetOitsflexuralperformancewerestudied.TheresultsshowthattheprestressedRPCboxgirdersdisplayagoo
5、ddeformationcapacity,withamaximaldeflectionof1/50ofitsspan.Thecrackwidthandtheshort—timestiffnessoftheRPCboxgirderscanbecalculatedaccordingtotheformulainTechnicalSpecificationforFiberReinforcedConcreteStructures(CECS38:2004),withacoefficientof0.4and0.2consideringinfluencefromsteelf
6、iber,respectively.ThetransverseprestressingforceinthetopplateofRPCboxgirdershaslittleinfluenceontheflexura1bearingcapacity,buttheforcecanmakeamoreuniformstraindistributionofthecompressiveconcreteSOastoreducetheshear—lageffectandincreasetheductilityofthespecimen.Byapplyingatransvers
7、eprestressingforceof2.95MPa(only3.1oftheRPCprismcompressivestrengthof94MPa)atthetopplate,theeffectivedistributionwidthofboxgirderincreasesby10,andductilityindexofspecimenincreasesby3.ThecalculatedformulatoevaluatethecrackingmomentandtheultimatemomentofaprestressedRPCboxgirdersis收稿日
8、期:2015-05—21基金項(xiàng)目:國家自然科學(xué)基金項(xiàng)