Inthisstudy,twotypesoffiberreinforcedpolymer(FRP)confinedconcretecylinderswereprepared.OnewasFRPjacketedconcretecylinders;theotherwasFRPtubeencasedconcretecylinders.Atotalof24jacketedcylindersand15encasedcylinderswereprepared.Forthejacketedcylinders,sixfiberorientationsandtwoFRPwallthicknesseswereused;fortheencasedcylinders,fourbatchesofconcretewithnormaltohighstrengthwereusedandbothbondedandunbondedinterfacialconditionswereconsidered.Itisfoundthatinsufficientlyconfinedcylindersbehavesimilartounconfinedcylinders.FRPcannotconfinetheconcretecoreuntiltheconcreteisdamaged(crackedorcrushed)duetothelargertransversePoisson'sratioandloweraxialstiffnessofFRP.Therateofincreaseinconfinementeffectivenessdecreasesnonlinearlyasconfinementratioincreases.Aconsiderabledeviationisfoundbetweenthepredictionbyexistingdesign-orientedconfinementmodelsandtestresults.
ExperimentalstudyofFRP-图一