Steel
reinforcement in concrete has the tendency to corrode and this process can lead
to structural damage. FRP
reinforcement represents a viable alternative for
structures exposed to aggressive environments and has many possible
applications where superior corrosion resistance properties are required. The
use of FRP rebars as internal reinforcements for concrete, however, is limited
to specific
structural elements and does not yet extend to the whole structure.
The reasons for this relate to the limited availability of curved or shaped
reinforcing elements on the market and their reduced structural performance.
Various studies, in fact, have shown that the mechanical performance of bent
portions of composite bars is reduced significantly under a multiaxial
combination of stresses and that the tensile strength can be as low as 40% of
the maximum tensile strength that can be developed in the straight part. In a
significant number of cases, the current design recommendations for concrete
structures reinforced with FRP, however, were found to overestimate the bend
capacity of FRP rebars. This paper presents an overview on the current use of
curved
reinforcement and discusses the problems related to the performance of
curved FRP bars embedded in concrete.