Studies On The Mechanical Properties Of Corroded Reinforced Concrete Columns Confined With CFRP

Steel corros ion is one o f the ma in reasons that which ca use concretedamage. For steel corros ion a large number of concrete structures ha ve to berepa ired, re inforced, or even be demo lis hed. Fiber reinforced compos ite (FRP)materia ls ha ve ma ny advantages, such as corrosio n resista nce, fatigue resista nce,lightwe ight, high strength, easy construction, good che mica l stability and othercharacteristics, etc. Gradua lly FRP is beco ming the firs t structure o f repa iringand reinforcing materia ls. Concrete structures confined by FRP can slow downthe further corros ion fro m corros ion; also the d uctility and mec hanica lproperties of the structure are significantly improved.At present, domestic and fore ign researchers have carried out exte ns iveresearch on Concrete structures confined with FRP, and achie ved fruitful results;they a lso found out some proble ms fro m the c urrent study o f FRP reinforcedconcrete. Firstly, most of researches mostly concerned on undama ged concretereinforceme nt confined by FRP, researches whic h concerned on reinforce mentof dama ged concrete are rare; in the actua l project, and dama ged structureswhic h need to be reinforced occup y a large proportion. Second ly, the crosssection shape of the reinforced concrete co lumns is mostly round, in the actua lproject, there are a lot of columns with square cross-section, and stress will beconcentrated in the corner with square co lumns confined by FRP, this artic leconsiders that it needs to change the section shape to reduce the stress in thecorner. There fore, expanding researches on dama ge concrete and squarecross-sectio n columns confined by FRP has a role in guid ing to practica lengineering.33Specime ns are made to get the mecha nical properties of columns of FRPjacketing a fter be ing cond itio ned to accelerated electroche mica l corrosio n, thetest results show that: the more of the stee l mass losses, the more loss of thespecimens’ ultimate bearing capacity; For CP columns, the lower strength of theconcrete, the better of the re inforc ing effect; For PC columns, with theaggra vation o f the steel corrosion, the ultimate bearing capacity of thespecimens losses more. In additio n, this paper has designed48square co lumns with cornerradius o f0mm,15mm,25mm,35mm,45mm,60mm, a nd75mm, this papercan get the mecha nica l properties fro m the specime ns confined by CFRP.Fro m the test results, with the steel corrosio n rate of20%, the ultima tebearing capacity of the RC columns confined by CFRP increases when thecorner radius becomes bigger.Fina lly, based on the test results, this paper establis hed strength mode l,peak strain model a nd stress-strain mode l, a fter calc ulatio n ver ificatio n, themodels have a good agreement with experimental results.