Avaliação do comportamento de vigas de concreto armadas com barras de fibra de vidro um estudo experimental

Abstract

Composites made of Fiber Reinforced Polymers (FRP) are a viable alternative in civil construction industry, due its excellent durability. Among several products made with this technology, non-metallic bars, made from glass, aramid, carbon and basalt fibers, for reinforcing concrete structures has being successfully worldwide used for over twenty years. This technology is somewhat new in Brazil. As seen in the technical literature, its fabrication process is mandatory in the further mechanical behaviour. Besides the bibliography research, this work focuses on the experimental analysis of four isostatic beams totally reinforced (longitudinal and transversally) with glass FRP bars. As a result of an extensive bibliographic review it was observed that in Brazil there is a lack of studies aimed at the analysis of shear behaviour of fully reinforced beams with GFRP bars. Thus, this work is considered pioneer in the analysis of this aspect and using material of national manufacture. In the specimens tested, the longitudinal and transversal ratios of GFRP reinforcement are the main assessed parameters. The experimental results achieved are compared to theoretical predictions and to the experimental results of an ordinary-steel reinforced concrete beam. Moment curvature, load deflection, moment deformation, and stirrups load deformation curves are presented. As seen in the literature, the experiments show that the performance of GFRP reinforced concrete beams are influenced by the relatively low elastic modulus of the reinforcement, the shape of the bars and the adhesion to concrete characteristics. The results shows, also, that the increase of reinforcement ratios improves the flexural and transverse behaviour. As a general remark, one can say that the use of GFRP reinforcement in concrete beams is a viable way to replace steel reinforcement, as long as its special characteristics are taken in to account in engineering projects.