ressedconcretemembersshouldtaketheconvertedsecondmomentofareaatthestrengtheningstage.Thedisplacementiscalculatedaccordingtothefollowingformula:cfecfcrMxMedsB()InwhichMcfe——bendingmomentcausedbyCFRPsheetsexistingpretensionatanysectionx;.AnalysisofrigidityRigidityBandBcraredecidedbyIandIcr.ThepaperistoderivethecalculationmethodofprestressedCFRPstrengtheningconcreteboxgirders’sectionIandIcrunderthepremisethatthedepthofthetensileareaiscoveredbytheweb(asshowninFig.).AccordingtoReference[],themembersworkwithcracks.Atthetensileareatheconcretefailsandtransformsthetensiononittothelongitudinalreinforcementwhichatthisstagedoesnotyieldandthecompressivestressoftheconcretetakestheshapeoftriangle.WiththeCFRPsheets,thesectionalareaofthesteelbarandCFRPsheetsshouldbeconvertedintotheconcretesectionalareawhichislocatedatthegravitycenterofthesteelbarandtheCFRPsheetsseparately.土预应力板梁组成部分通常会受到荷载作用;钢筋在受到拉应变作用同时,受拉区混凝土可能已经产生裂缝。
&