SERVICEABILITY OF CONCRETE BEAMS PRESTRESSED BY CARBON-FIBER-REINFORCED-PLASTIC BARS

The use of carbon-fiber-reinforced-plastic (CFRP) as prestressing rein forcement for concrete structures, has increased rapidly in the last t en years. The non-corroding characteristics of CFRP reinforcement coul d significantly increase the service life of concrete structures. In a ddition, CFRP prestressing reinforcement has the advantages of high st rength-to-weight ratio, good fatigue properties, and low relaxation. H owever; the linear elastic behavior of the material up to failure requ ires special design consideration to ensure sufficient deformability o f the members. In this paper, partial prestressing using low-jacking s tresses, is proposed for the design of concrete members prestressed by CFRP reinforcement to reduce the cost and improve their deformability . The paper summarizes a study undertaken to examine the flexural beha vior of concrete beams partially prestressed by CFRP reinforcement. Th e experimental program consists of testing eight concrete beams prestr essed by CFRP bars and two beams prestressed by conventional steel str ands. The parameters considered in this experimental program are the p restressing ratio, degree of prestressing, and distribution of the CFR P bars iii the tension zone. The various limit stares behavior of conc rete beams prestressed by CFRP bars in terms of cracking and deflectio n prior and after cracking are examined. The different modes of failur e and the deformability of such beams are discussed.