Study of strengthening reinforced concrete beam using prestressed carbon fiber sheet

Abstract

This paper presents a primary study o f strengthening reinforced concrete beam using prestressed carbon fiber reinforced plastics(CFRP)sheet and its constructional technology of strengthening and prestress ing.A total of 9speci-mens were tested to investigate the f lexural behavior of these beams.The strengthened beams using prestressed carbon fiber sheet were compared with stren gthened beams using non-prestresse d carbon fiber sheet on the propertie s of cracking load ,ultimate load and flexural stiffness to determine the effects of pr estressing force on these behavior.In addition,the variation of yield strength and defo rmations related to the different pr estress levels were discussed.It is shown that strengthening the beams with prestr essed CFRP sheet enhances the crack l oad by 43%to 214%;and the deformatio ns of these beams at the yield load are only29.8%to 56.3%of those strengthened with CFRP sheet without prestress.Experimental results and analysis s how that prestressing CFRP can impro ve greatly the performance of the beams.Furthermore,the equations for comp uting the limit ratio of strengthein g reinforcement,cracking load,ultimate load and deflection of such beams are propose d.