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1、第42卷第9期土木工程学报Vol.42No.92009年9月CHINACIVILENGINEERINGJOURNALSep.2009预应力与非预应力AFRP加固腐蚀钢筋混凝土梁疲劳性能研究邓宗才李凯(北京工业大学,北京100022)摘要:对非预应力芳纶布(AFRP)加固和带永久锚具的预应力AFRP加固锈蚀钢筋混凝土梁的疲劳性能进行研究。通过疲劳试验,探讨预应力水平和钢筋锈蚀程度对加固梁疲劳破坏机制、疲劳寿命、挠度等的影响。试验结果表明:预应力AFRP与非预应力加固梁的疲劳破坏机制相同,都为纵筋的疲劳断裂;预应力AFRP加固锈蚀混凝土梁的抗疲劳特性明显优于非预应力加固梁;预应力水平越
2、高,中度腐蚀梁加固后疲劳寿命越高;锈蚀率越高,梁的疲劳寿命越低,重度锈蚀梁疲劳寿命的降低幅度比中度锈蚀梁更明显。通过与光面钢筋对比,获得锈蚀纵筋的等效疲劳切口系数Kf。结果表明,钢筋锈蚀率的增加会导致Kf增大,从而导致锈蚀梁疲劳寿命明显降低。基于试验结果,建立了预应力AFRP加固中度腐蚀钢筋混凝土梁疲劳寿命的计算公式,供桥梁加固设计参考。关键词:锈蚀;预应力;AFRP;混凝土梁;疲劳中图分类号:TU375文献标识码:A文章编号:1000-131X(2009)-09-0054-07Experimentalstudyonfatigueperformancecorrodedreinfor
3、cedconcretebeamsstrengthenedwithprestressedAFRPsheetsDengZongcaiLiKai(BeijingUniversityofTechnology,Beijing100022,China)Abstract:AstudywascarriedoutforthefatiguebehaviorofcorrodedRCbeamsstrengthenedbynon-prestressedaramidfiberreinforcedpolymer(AFRP)sheetsandprestressedAFRPsheetswithpermanentan
4、chors.Basedonthefatiguetestresults,theeffectsofdifferentpre-stresslevelsofAFRPsheetsunderdifferentcorrosionratios(moderatelycorroded:reinforcementmassloss6.0%,severelycorroded:reinforcementmassloss12%)onthepropertiesofthefatiguefailure,fatiguelifeandmid-spandeflectionwereanalyzed.Themajorcause
5、ofthefatigueofthecorrodedRCbeamsstrengthenedwithAFRPsheetsisthefatiguefractureofthesteelbars.ThefatiguelifeofthebeamsstrengthenedwithprestressedAFRPsheetswaslongerthanthatofthosebeamswithnon-prestressedAFRPsheets.ThefatiguelifeofthemoderatelycorrodedRCbeamsincreasedwiththepre-stresslevelsofAFR
6、Psheets,andthefatiguelifeofthecorrodedRCbeamsdecreasewiththeratioofcorrosion.Thefatigueresultswerecomparedtothefatiguedataofsmoothbarstoestimateanequivalentfatiguenotchfactorforthemainreinforcementbarsofthetestedspecimens.Pittingcorrosionresultedinanincreaseinthefatiguenotchfactor,whichinturnr
7、esultedinasignificantreductionoffatiguelife.BasedontheexperimentalresultsofmoderatecorrodedconcretebeamsstrengthenedwithAFRPsheets,thefatigueequationwasobtained,andthisequationcanbeusedinstrengtheneddesignfordamagedbridge.Keywords:corro
