RC T beams strengthened to shear with carbon fibre composites

Resumo

This paper presents the experimental data of the behaviour of reinforced concrete beams strengthened to shear with carbon fibre composites. The tests were composed of eight T beams, , , flange width , flange height , and length , divided into two series with the same longitudinal steel reinforcement and a reference beam without strengthening in each series. The beams had two types of arrangement of internal steel stirrups and two different types of anchorage of external carbon fibre composite U stirrups. The test variables were the internal and external geometric ratio of the transverse reinforcement and the number of layers of carbon fibre composites stirrups. All the beams were loaded at two points. The strengthened beams were submitted to a preloading and the strengthening was applied to the cracked beam. All the beams were designed in order to guarantee shear failure, and the ultimate load of the strengthened beams was 36% to 54% greater than the reference beams. The Cracking Sliding Model applied to the strengthened beams was evaluated and showed good agreement with the experimental results.