Ductility of RC beams with FRP reinforcing bars

Abstract

Concrete structures with steel reinforcing bars are wlnerable to damage by corrosion most of all in coastal areas. A very common practice has been, for many years, to increase the amount of concrete covering, in order to protect the reinforcing bars against corrosion. Increasing the concrete covering, not only increases the structure's weight, but also the cost. RC beams with f'Rp rebars are a very good solution, with regard to the corrosion problem. The behaviour of RC beams with glass FRP reinforciilg bars is studied in this research. The Young's modulus of glass FRP rebars is significantly lower than steel rebars causing, therefore, the problem of large deflections. Over reinforcing the beams with FRP rebars, guarantee stiffness, however, the beams also become brittle. Brittle failure can be prevented with the addition of FRP compressive reinforcement to the beam which is the subject ofthis thesis. Beam specimens, with different combinations of longitudinal reinforcement, have been tested. It was found that, RC beams, with compressive reinforcement have a very good ductile behaviour. The beams were designed using a segmental analysis, and a mathematical model has been developed to facilit¿te the design by hand of ductile RC beams with FRP reinforcing bars.